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DAVID HARDT: My name is
David Hardt for those of you

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00:00:22,730 --> 00:00:24,140
who I haven't met yet.

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00:00:24,140 --> 00:00:27,620
And I'm filling in
for Duane Boning

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00:00:27,620 --> 00:00:30,755
today or sitting in or
guest lecturing, whatever

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00:00:30,755 --> 00:00:31,630
you want to call it--

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00:00:31,630 --> 00:00:32,070
AUDIENCE: You're
not guest lecturing.

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You're co-lecturing.

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00:00:32,570 --> 00:00:33,530
DAVID HARDT: Oh, yeah,
I'm a co-lecturer.

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00:00:33,530 --> 00:00:33,850
Yeah.

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00:00:33,850 --> 00:00:34,460
Yeah, that's right.

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00:00:34,460 --> 00:00:36,005
No, I'm guest
lecturing because--

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00:00:36,005 --> 00:00:38,190
you know the story.

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00:00:38,190 --> 00:00:46,580
So I think my role today is
to in some ways repeat what

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00:00:46,580 --> 00:00:49,010
Duane Boning has talked about
in the first two lectures

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00:00:49,010 --> 00:00:52,040
from a little bit more of
a mechanical engineering

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00:00:52,040 --> 00:00:52,610
perspective.

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00:00:52,610 --> 00:00:56,570
But I'm going to also
throw in some things,

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00:00:56,570 --> 00:01:00,140
you might just say a personal
perspective on the problem.

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00:01:00,140 --> 00:01:05,030
And I've got too much to
try and do in one lecture,

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00:01:05,030 --> 00:01:07,790
but that's sort of
typical of me anyway.

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00:01:07,790 --> 00:01:09,950
But the notes are
on the web if you

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00:01:09,950 --> 00:01:12,643
want for the things
I have to skip over.

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00:01:12,643 --> 00:01:14,060
Now, the first
part of the lecture

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is to notice this scene.

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00:01:16,790 --> 00:01:18,483
And someone was
pointing out to me

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00:01:18,483 --> 00:01:20,900
the other day, said, it must
be tough for you this summer,

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00:01:20,900 --> 00:01:25,130
because you go between
these extreme environments.

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00:01:25,130 --> 00:01:28,242
So I found this picture of
what I call a tree tunnel.

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00:01:28,242 --> 00:01:30,200
Does anybody know where
this picture was taken?

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00:01:33,120 --> 00:01:34,772
In January.

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00:01:34,772 --> 00:01:37,480
AUDIENCE: [INAUDIBLE]

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00:01:37,480 --> 00:01:39,580
DAVID HARDT: It wasn't at MIT?

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00:01:39,580 --> 00:01:40,660
It's a little washed out.

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So you can't see what these
things are in the distance.

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00:01:44,500 --> 00:01:46,600
If you saw those you'd
probably know in an instant

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00:01:46,600 --> 00:01:48,004
if you know--

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00:01:48,004 --> 00:01:49,300
AUDIENCE: Barges?

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00:01:49,300 --> 00:01:51,040
DAVID HARDT:
Anybody in Singapore

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00:01:51,040 --> 00:01:54,600
know what that picture
might be taken?

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00:01:54,600 --> 00:01:57,740
Oh, come on.

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00:01:57,740 --> 00:02:01,292
All right, where do you
think this picture was taken?

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00:02:01,292 --> 00:02:02,240
AUDIENCE: Outside.

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00:02:02,240 --> 00:02:03,782
DAVID HARDT: All
right, OK, so here's

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00:02:03,782 --> 00:02:08,660
a tree tunnel in Acton,
Massachusetts, in January.

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00:02:08,660 --> 00:02:11,390
And here's a tree
tunnel on Sentosa island

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in Singapore in January,
just about the same time,

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same kind of view.

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The difference is that
those are probably

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the second largest collection
of container ships in the world,

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something like that, which is
the main landscape feature off

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of that coast of Singapore.

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OK, just to let everybody
know what the other side

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is enjoying on their weekends.

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00:02:34,790 --> 00:02:38,030
So here's what I want
to try to do today.

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00:02:38,030 --> 00:02:40,100
I want to go back and
talk a little bit more

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about process definitions
from the point of view

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of geometric change
of an object.

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And I think Duane
has already talked

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about this a fair amount.

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But I want to relate it to that
model or that view of processes

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to a couple key mechanical
processes as examples.

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And then something
that we always do

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is talk about this
taxonomy for control.

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It's a framework.

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It's all these
rather abstract terms

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that say, here's a
way for you to think

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00:03:10,280 --> 00:03:13,490
about every process
that's ever been invented

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and try to understand how it
relates to some other process,

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00:03:16,910 --> 00:03:19,100
with respect to
things that affect

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how we control the process.

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So that's our
taxonomy for control.

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And then we'll go through a
couple mechanical examples.

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I'll use the process of simple
machining, a turning process,

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a blending process,
and a molding process.

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We used to have a lab in
the course that we did--

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in fact, the guys in
Singapore did it this summer

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as part of their
summer orientation.

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They actually did
this lab where they

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went through and made parts
using these three processes.

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And we studied the process
control aspect to that.

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And they're
ubiquitous processes,

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00:03:53,060 --> 00:03:57,560
but they also can be reduced
to some simple enough concepts

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that you can try to understand
this idea of the origins

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00:04:00,590 --> 00:04:03,080
of variation, why
did things vary,

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00:04:03,080 --> 00:04:08,332
instead of it being a
purely random event,

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00:04:08,332 --> 00:04:10,040
instead of sort of
throwing up your hands

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00:04:10,040 --> 00:04:12,230
and saying, I have no idea
why anything happened,

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00:04:12,230 --> 00:04:14,510
let's just model it
as a random process,

96
00:04:14,510 --> 00:04:17,300
we say, no, let's try to
see if we can separate

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00:04:17,300 --> 00:04:21,170
those things that have a clear
cause, which we may or may not

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00:04:21,170 --> 00:04:23,960
be able to control, and those
things that we just don't know

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00:04:23,960 --> 00:04:25,730
about.

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00:04:25,730 --> 00:04:28,580
And then scrambling
at the end, I'll

101
00:04:28,580 --> 00:04:33,530
try to get to this concept
of states and properties.

102
00:04:33,530 --> 00:04:35,690
And again, this is more
of a framework issue.

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00:04:35,690 --> 00:04:40,190
But it is an issue of
looking at any process,

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00:04:40,190 --> 00:04:43,160
looking at all the
different factors that

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00:04:43,160 --> 00:04:45,830
enter into the
outcome of the process

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00:04:45,830 --> 00:04:53,090
and just parsing it really into
four areas in this idea of what

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00:04:53,090 --> 00:04:55,340
we'll end up calling
thermodynamics states,

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00:04:55,340 --> 00:04:58,070
those things that are kind
of transient, come and go,

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and properties,
those things that

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00:04:59,510 --> 00:05:01,400
are inherent in the process.

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00:05:01,400 --> 00:05:02,870
And then we'll
separate the process

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00:05:02,870 --> 00:05:07,040
into the equipment that executes
the process, which kind stays

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00:05:07,040 --> 00:05:09,740
there day after day
and year after year,

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00:05:09,740 --> 00:05:12,830
and the material
that you're changing

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00:05:12,830 --> 00:05:13,820
as part of the process.

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00:05:13,820 --> 00:05:16,370
And, of course, that changes
in every cycle of the process.

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00:05:16,370 --> 00:05:21,030
And that distinction between
the two is extremely important.

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00:05:21,030 --> 00:05:23,240
So here's the model
you've already seen.

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00:05:23,240 --> 00:05:27,200
And the first part
of this is to notice

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00:05:27,200 --> 00:05:30,080
that we've taken the
manufacturing process and said,

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00:05:30,080 --> 00:05:33,270
well, again, there are
these two elements to it.

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00:05:33,270 --> 00:05:39,110
There's the material, which is
again sort of coming and going.

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00:05:39,110 --> 00:05:42,380
And by its very nature, the
fact that every time you

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00:05:42,380 --> 00:05:44,630
run the process,
there's a new piece

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00:05:44,630 --> 00:05:46,370
of material in
there, that's going

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00:05:46,370 --> 00:05:48,410
to have a different
characteristic

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00:05:48,410 --> 00:05:52,640
for its variability than the
equipment, which, again, is

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00:05:52,640 --> 00:05:56,660
unless you buy disposable
equipment, you generally

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00:05:56,660 --> 00:05:59,810
keep around for years.

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00:05:59,810 --> 00:06:02,030
And then there's an
interaction between the two.

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00:06:02,030 --> 00:06:06,140
And that interaction, if you
really want to abstract it,

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00:06:06,140 --> 00:06:08,870
could be called a
directed energy exchange.

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00:06:08,870 --> 00:06:12,380
It always takes some energy to
cause the material to change.

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00:06:12,380 --> 00:06:13,860
And what are you
trying to change?

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00:06:13,860 --> 00:06:18,410
You're trying to change
its geometry, usually only

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00:06:18,410 --> 00:06:19,460
its geometry.

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00:06:19,460 --> 00:06:21,710
Often properties change
as a result of that.

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00:06:21,710 --> 00:06:23,690
Or sometimes you're
changing properties,

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00:06:23,690 --> 00:06:27,000
like a hardening process or
ion implantation, something

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00:06:27,000 --> 00:06:27,500
like that.

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00:06:27,500 --> 00:06:30,470
You're taking one material
and through this process

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00:06:30,470 --> 00:06:34,380
transforming it in some way.

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00:06:34,380 --> 00:06:37,300
And, again, just
to remind you, we

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00:06:37,300 --> 00:06:39,690
have this simple functional
relationship that says,

145
00:06:39,690 --> 00:06:42,493
well, guess what, the output is
a function of all the inputs.

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00:06:42,493 --> 00:06:43,910
And that's really
all it's saying.

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00:06:43,910 --> 00:06:48,920
And defining it right now,
saying that the outputs are

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00:06:48,920 --> 00:06:49,700
some vector--

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00:06:49,700 --> 00:06:53,510
or the outputs can be
described as a vector, which

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00:06:53,510 --> 00:06:55,790
has all of the relevant
geometry and property

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00:06:55,790 --> 00:06:58,890
characteristics of the process.

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00:06:58,890 --> 00:07:01,430
So it would be dimensions,
material properties,

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00:07:01,430 --> 00:07:03,560
things like that.

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00:07:03,560 --> 00:07:07,370
And process parameters,
using a really generic word

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00:07:07,370 --> 00:07:09,230
for those input
variables, because I'm

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00:07:09,230 --> 00:07:12,150
going to distinguish between
inputs and parameters

157
00:07:12,150 --> 00:07:15,560
a little bit later,
and just saying

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that there's some functional
relationship between the two.

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00:07:18,490 --> 00:07:21,110
And, of course, here's the
functional relationship,

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00:07:21,110 --> 00:07:23,150
all that stuff that's in there.

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00:07:27,230 --> 00:07:33,540
So if we just focus for
a moment on processes

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00:07:33,540 --> 00:07:37,210
where geometry change is
the most important one--

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00:07:37,210 --> 00:07:40,920
and I don't know, speaking from
my perspective on this class,

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00:07:40,920 --> 00:07:44,248
that's going to be 100%
of what I talk about.

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00:07:44,248 --> 00:07:45,915
I think when we get
into semiconductors,

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00:07:45,915 --> 00:07:49,650
there's a little bit more
on material modification.

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But I think certainly most
of the stuff you've seen

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00:07:51,840 --> 00:07:54,540
has been on a
manufacturing process,

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00:07:54,540 --> 00:07:58,260
meaning we change the geometry.

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00:07:58,260 --> 00:08:00,040
Now, what causes the
output to change?

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00:08:00,040 --> 00:08:04,020
Well, there's a directed energy
exchange with the equipment.

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00:08:04,020 --> 00:08:07,650
And that energy
exchange can take

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00:08:07,650 --> 00:08:10,840
the form of any of the
relevant forms of energy.

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00:08:10,840 --> 00:08:12,847
So we could have a
mechanical exchange,

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00:08:12,847 --> 00:08:15,180
where you impose a force or
a displacement on something.

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00:08:15,180 --> 00:08:16,805
We can have an
electrical change, where

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00:08:16,805 --> 00:08:18,540
you run a current
through something,

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00:08:18,540 --> 00:08:22,920
or have an electric arc
something like that.

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00:08:22,920 --> 00:08:24,565
It could be thermal.

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00:08:24,565 --> 00:08:26,190
And certainly, there
are many processes

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where the transfer of
heat is the key way

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00:08:30,540 --> 00:08:32,039
that you change a geometry.

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00:08:32,039 --> 00:08:33,539
And certainly, it
could be chemical.

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00:08:33,539 --> 00:08:35,622
Think of an etching process
or anything like that.

185
00:08:35,622 --> 00:08:40,200
All of these energies
directed the correct way

186
00:08:40,200 --> 00:08:46,960
can be thought of as
geometry change mechanisms.

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00:08:46,960 --> 00:08:50,260
Now, how do we
direct this energy?

188
00:08:50,260 --> 00:08:55,410
If I just say, I've got some
thermal energy sitting around.

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00:08:55,410 --> 00:08:57,675
How do I make sure it
goes to the right place?

190
00:09:02,320 --> 00:09:04,570
In effect, that's the
goal of the equipment.

191
00:09:04,570 --> 00:09:06,820
That's why this one
little thing, which

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00:09:06,820 --> 00:09:08,840
my thermodynamics friends
would go crazy with,

193
00:09:08,840 --> 00:09:10,930
but calling energy
a vector quantity.

194
00:09:13,940 --> 00:09:17,120
It matters where you
put the energy, right?

195
00:09:17,120 --> 00:09:21,410
If I want to take this
bar and maybe do something

196
00:09:21,410 --> 00:09:26,570
to the center of it thermally,
and I've got a thermal energy

197
00:09:26,570 --> 00:09:29,030
source out here called
a piece of equipment,

198
00:09:29,030 --> 00:09:31,320
maybe a torch or
something like that,

199
00:09:31,320 --> 00:09:33,400
how do I make sure it
goes to the right place?

200
00:09:37,860 --> 00:09:39,165
Equipment, material.

201
00:09:44,160 --> 00:09:46,950
This is one of my
easy questions.

202
00:09:46,950 --> 00:09:49,650
I make sure I hold
it in place, right?

203
00:09:49,650 --> 00:09:50,580
Yeah, go ahead.

204
00:09:50,580 --> 00:09:52,130
Go ahead.

205
00:09:52,130 --> 00:09:56,390
AUDIENCE: So I guess by way
of relative positioning,

206
00:09:56,390 --> 00:09:58,370
these two are in the
correct positions.

207
00:09:58,370 --> 00:10:00,680
DAVID HARDT: Yeah, I mean if
I had like a point source,

208
00:10:00,680 --> 00:10:03,830
a laser or an arc, or
something like that--

209
00:10:03,830 --> 00:10:05,150
laser is a better example--

210
00:10:05,150 --> 00:10:07,910
and I needed to do
something right here,

211
00:10:07,910 --> 00:10:11,360
maybe thermally
deform this or join it

212
00:10:11,360 --> 00:10:13,220
or something like
that, then the key

213
00:10:13,220 --> 00:10:20,510
would be how both the value of
that energy and where I put it.

214
00:10:20,510 --> 00:10:24,240
So location would
be really important.

215
00:10:24,240 --> 00:10:26,420
So that's one way of
thinking of the concept

216
00:10:26,420 --> 00:10:27,757
of a directed energy source.

217
00:10:27,757 --> 00:10:29,840
If I want to bend this
piece of sheet metal, which

218
00:10:29,840 --> 00:10:36,860
was originally flat, and I
have a displacement device,

219
00:10:36,860 --> 00:10:40,820
it's probably a good idea for me
to put that displacement device

220
00:10:40,820 --> 00:10:44,210
in the middle, not
over here, and to have

221
00:10:44,210 --> 00:10:47,660
that displacement device
have a certain shape

222
00:10:47,660 --> 00:10:49,970
to get what I want.

223
00:10:49,970 --> 00:10:51,860
Think about this one
for a second this one.

224
00:10:51,860 --> 00:10:53,235
I don't know if
you can see this.

225
00:10:53,235 --> 00:10:58,200
Let me try my document camera.

226
00:10:58,200 --> 00:10:59,830
Come on, doc cam.

227
00:10:59,830 --> 00:11:02,110
There we go.

228
00:11:02,110 --> 00:11:04,650
This is an injection
molded part.

229
00:11:04,650 --> 00:11:07,530
It's from a precision yo-yo.

230
00:11:07,530 --> 00:11:14,260
And what's the energy
we're talking about there?

231
00:11:14,260 --> 00:11:15,413
This was injection molded.

232
00:11:15,413 --> 00:11:17,830
I think most of you here have
had some hands on experience

233
00:11:17,830 --> 00:11:19,600
with injection molding.

234
00:11:19,600 --> 00:11:22,510
If you haven't, I'll
explain it in a few minutes.

235
00:11:22,510 --> 00:11:27,040
But where's my directed
energy source there?

236
00:11:27,040 --> 00:11:29,080
Or if you have any
trouble getting your head

237
00:11:29,080 --> 00:11:31,750
around that, how did I
come up with that shape?

238
00:11:34,942 --> 00:11:36,375
AUDIENCE: Heat and pressure.

239
00:11:36,375 --> 00:11:38,000
DAVID HARDT: If I
had heat and pressure

240
00:11:38,000 --> 00:11:42,900
to put the liquid
plastic in there,

241
00:11:42,900 --> 00:11:44,340
that kind of filled the mold.

242
00:11:44,340 --> 00:11:46,050
But what determined the shape?

243
00:11:46,050 --> 00:11:47,040
AUDIENCE: The mold.

244
00:11:47,040 --> 00:11:48,450
DAVID HARDT: Yeah, the mold.

245
00:11:48,450 --> 00:11:51,710
And what's the directed
energy in this case?

246
00:11:51,710 --> 00:11:55,830
If I'm saying the direct energy
leads to the shape of the part,

247
00:11:55,830 --> 00:11:57,745
the geometry change--

248
00:11:57,745 --> 00:11:58,620
AUDIENCE: The forces.

249
00:11:58,620 --> 00:12:00,030
DAVID HARDT: Pardon me.

250
00:12:00,030 --> 00:12:01,740
AUDIENCE: The mill
cutting courses

251
00:12:01,740 --> 00:12:05,402
from whatever bit
used to cut the metal.

252
00:12:05,402 --> 00:12:07,860
DAVID HARDT: We're talking
about plastic molding right now.

253
00:12:07,860 --> 00:12:08,110
AUDIENCE: Right.

254
00:12:08,110 --> 00:12:09,020
But to make the mold.

255
00:12:09,020 --> 00:12:10,802
DAVID HARDT: Oh,
to make the mold.

256
00:12:10,802 --> 00:12:12,510
Yeah, I see where
you're going with that.

257
00:12:12,510 --> 00:12:14,550
But I'm thinking about
just the molding process.

258
00:12:14,550 --> 00:12:18,540
The tooling somehow
was magically there.

259
00:12:18,540 --> 00:12:22,680
AUDIENCE: I think the directed
energy in front of the surface.

260
00:12:22,680 --> 00:12:26,490
So everywhere where we have
surface, we direct energy.

261
00:12:26,490 --> 00:12:27,750
DAVID HARDT: Exactly.

262
00:12:27,750 --> 00:12:31,680
So now, the one big
distinction between these two

263
00:12:31,680 --> 00:12:35,340
is that here it was pretty
clear that I had a pretty

264
00:12:35,340 --> 00:12:39,330
localized source of energy.

265
00:12:39,330 --> 00:12:41,970
And, of course, the case of
heating this would be the same.

266
00:12:41,970 --> 00:12:49,650
Or as you'll see later,
turning with a pointed tool.

267
00:12:49,650 --> 00:12:52,290
Here, everything's happening
everywhere at once.

268
00:12:52,290 --> 00:12:56,610
And the direction, if you
will, the spatial aspect of it

269
00:12:56,610 --> 00:12:59,130
is imbued not by how
I position something,

270
00:12:59,130 --> 00:13:02,500
but by the shape of the tool.

271
00:13:02,500 --> 00:13:05,400
So you start to see that they're
kind of two extremes here.

272
00:13:05,400 --> 00:13:08,340
There's the case where
this geometry is determined

273
00:13:08,340 --> 00:13:12,900
primarily by a spatial
distribution of energy

274
00:13:12,900 --> 00:13:15,630
exchange, which is
stretching it a little bit

275
00:13:15,630 --> 00:13:18,360
here, but a shaped tool.

276
00:13:18,360 --> 00:13:20,640
And as Simon said,
everything happens everywhere

277
00:13:20,640 --> 00:13:23,370
at the same time.

278
00:13:23,370 --> 00:13:27,780
Whereas in this case,
things are changing

279
00:13:27,780 --> 00:13:32,530
over time and quite
different things

280
00:13:32,530 --> 00:13:33,780
happening at different places.

281
00:13:33,780 --> 00:13:36,780
And an more extreme case
again, which I'll get to later,

282
00:13:36,780 --> 00:13:40,230
is if I'm coming in here with
some sort of a point source--

283
00:13:40,230 --> 00:13:42,990
let's say heating it or
applying a force here--

284
00:13:42,990 --> 00:13:44,820
there's nothing
happening out here.

285
00:13:44,820 --> 00:13:47,220
It's all happening right here.

286
00:13:47,220 --> 00:13:49,740
And the net shape that
I get has a lot more

287
00:13:49,740 --> 00:13:53,730
to do with how I move
that interaction port,

288
00:13:53,730 --> 00:13:57,690
otherwise known as a tool, than
it does with the tool shape.

289
00:13:57,690 --> 00:14:00,600
Tool shape is important, but
it's of secondary importance.

290
00:14:00,600 --> 00:14:01,100
OK?

291
00:14:07,300 --> 00:14:09,900
They're supposed to go away now.

292
00:14:09,900 --> 00:14:11,980
There we go.

293
00:14:11,980 --> 00:14:13,120
OK.

294
00:14:13,120 --> 00:14:15,010
Well, they didn't go away.

295
00:14:15,010 --> 00:14:18,100
It's good to see you guys.

296
00:14:18,100 --> 00:14:25,320
So now, we talk
about it and we say,

297
00:14:25,320 --> 00:14:26,670
it's about geometry change.

298
00:14:26,670 --> 00:14:29,400
And I've kind of thrown out
some different ones here.

299
00:14:29,400 --> 00:14:32,813
How do you change the
shape of anything?

300
00:14:32,813 --> 00:14:34,230
Well, we already
talked about one.

301
00:14:34,230 --> 00:14:35,063
It's pretty obvious.

302
00:14:35,063 --> 00:14:37,140
Take out a knife
and a piece of wood

303
00:14:37,140 --> 00:14:40,650
and you can change its shape
by removing wood chips.

304
00:14:40,650 --> 00:14:44,760
Whittling, that's your
basic shaping technique.

305
00:14:44,760 --> 00:14:48,390
Well, that's essentially
one of the most common ways

306
00:14:48,390 --> 00:14:49,800
of making anything.

307
00:14:49,800 --> 00:14:53,160
We etch away silicon.

308
00:14:53,160 --> 00:14:57,660
We machine away material.

309
00:14:57,660 --> 00:15:01,170
We can oxidize and
burn things off.

310
00:15:01,170 --> 00:15:04,650
We can do it in a number
of different ways.

311
00:15:04,650 --> 00:15:06,330
So removal of
material is obviously

312
00:15:06,330 --> 00:15:08,300
one way of doing things.

313
00:15:08,300 --> 00:15:09,400
Pretty obvious one.

314
00:15:09,400 --> 00:15:13,480
How else can I change
the shape of something?

315
00:15:13,480 --> 00:15:15,635
AUDIENCE: You can add material.

316
00:15:15,635 --> 00:15:17,240
DAVID HARDT: I can
add material to it.

317
00:15:17,240 --> 00:15:17,810
Yeah.

318
00:15:17,810 --> 00:15:19,980
Or join or something like that.

319
00:15:19,980 --> 00:15:22,880
So I can reform things.

320
00:15:22,880 --> 00:15:25,647
OK, how else?

321
00:15:25,647 --> 00:15:27,230
AUDIENCE: You can
deform the material.

322
00:15:27,230 --> 00:15:29,495
DAVID HARDT: I can deform
the material like this.

323
00:15:29,495 --> 00:15:32,960
This started out, it's a
fixed piece of material.

324
00:15:32,960 --> 00:15:34,920
I didn't add or
subtract anything to it.

325
00:15:34,920 --> 00:15:39,210
But I changed the
shape by bending it.

326
00:15:39,210 --> 00:15:39,990
How else?

327
00:15:39,990 --> 00:15:42,090
Let me see what I've got here.

328
00:15:42,090 --> 00:15:44,010
Plastic deformation
of the material.

329
00:15:44,010 --> 00:15:47,900
So a constant volume,
constant mass process.

330
00:15:47,900 --> 00:15:52,220
The first case, you're
throwing material away.

331
00:15:52,220 --> 00:15:55,190
Adding material, which I think
is what people were already

332
00:15:55,190 --> 00:15:58,040
talking about.

333
00:15:58,040 --> 00:16:01,760
So one of my famous
professors here at MIT

334
00:16:01,760 --> 00:16:05,243
called this machining
and negative machining.

335
00:16:05,243 --> 00:16:07,160
So it's kind of another
way of thinking of it,

336
00:16:07,160 --> 00:16:09,810
but adding material,
subtracting material.

337
00:16:09,810 --> 00:16:11,840
The ultimate
manufacturing tool would

338
00:16:11,840 --> 00:16:15,230
be one that took from
here and gave to there

339
00:16:15,230 --> 00:16:17,180
and that sort of thing.

340
00:16:17,180 --> 00:16:17,760
What else?

341
00:16:17,760 --> 00:16:20,300
There's one other?

342
00:16:20,300 --> 00:16:21,950
Where does this fit in?

343
00:16:21,950 --> 00:16:23,150
It doesn't fit any of those.

344
00:16:25,892 --> 00:16:27,270
AUDIENCE: Formation.

345
00:16:27,270 --> 00:16:29,308
DAVID HARDT: Yeah, you
guys took 2810, right?

346
00:16:29,308 --> 00:16:30,850
So you probably
already covered this.

347
00:16:30,850 --> 00:16:33,810
But, yes, formation
of material, so where

348
00:16:33,810 --> 00:16:38,580
you go from a liquid
or vapor state,

349
00:16:38,580 --> 00:16:43,890
it solidifies against some
energy exchange medium or form

350
00:16:43,890 --> 00:16:44,400
tool.

351
00:16:44,400 --> 00:16:45,733
And you come up with that shape.

352
00:16:45,733 --> 00:16:46,770
OK.

353
00:16:46,770 --> 00:16:47,670
What else?

354
00:16:47,670 --> 00:16:48,480
That's only four?

355
00:16:53,730 --> 00:16:56,010
This is every
manufacturing process

356
00:16:56,010 --> 00:16:57,600
in the world in the universe.

357
00:16:57,600 --> 00:16:59,433
AUDIENCE: Well, it's
kind of under addition.

358
00:16:59,433 --> 00:17:01,170
But you're actually
growing material,

359
00:17:01,170 --> 00:17:03,650
using chemical,
biological process,

360
00:17:03,650 --> 00:17:05,040
like a silicon crystal.

361
00:17:05,040 --> 00:17:06,150
DAVID HARDT: OK, good.

362
00:17:06,150 --> 00:17:09,480
We'll call that addition.

363
00:17:09,480 --> 00:17:12,950
It ruins my punch
line if we don't.

364
00:17:12,950 --> 00:17:15,790
Any others?

365
00:17:15,790 --> 00:17:21,069
Well, I mean the
point is that again it

366
00:17:21,069 --> 00:17:23,859
is a matter of definitions, and
you could cut this more finely.

367
00:17:23,859 --> 00:17:26,589
But this pretty
nicely characterizes

368
00:17:26,589 --> 00:17:29,650
every manufacturing process
with respect to geometry change.

369
00:17:29,650 --> 00:17:32,940
We could have a parallel
set for property changes,

370
00:17:32,940 --> 00:17:36,190
thermodynamic changes
and implantation changes,

371
00:17:36,190 --> 00:17:38,030
atomic changes, so
forth and so on.

372
00:17:38,030 --> 00:17:42,950
But for this it seems to
cover pretty much everything.

373
00:17:42,950 --> 00:17:45,358
So if you look at a
manufacturing process

374
00:17:45,358 --> 00:17:47,650
or you look at something
going on in a factory and say,

375
00:17:47,650 --> 00:17:49,775
is this a manufacturing process?

376
00:17:49,775 --> 00:17:51,400
One of these things
should be going on,

377
00:17:51,400 --> 00:17:55,280
if it's a geometry
change process.

378
00:17:55,280 --> 00:17:58,370
So what controls
the geometry change?

379
00:17:58,370 --> 00:18:01,482
Was, who said, the
location and intensity

380
00:18:01,482 --> 00:18:02,440
of the energy exchange.

381
00:18:02,440 --> 00:18:04,510
So we already talked
about this for turning.

382
00:18:04,510 --> 00:18:07,327
And here's just a schematic
of a simple turning.

383
00:18:07,327 --> 00:18:09,910
This is actually the experiment
we used to do where you just--

384
00:18:09,910 --> 00:18:11,952
or you guys actually did
it again, where you just

385
00:18:11,952 --> 00:18:14,470
come in so-called orthogonal
turning, and you come in

386
00:18:14,470 --> 00:18:17,095
and reduce the
diameter of this stock.

387
00:18:20,110 --> 00:18:23,530
And more formally, we would
say this is the location

388
00:18:23,530 --> 00:18:25,060
of the maximum shear stress.

389
00:18:25,060 --> 00:18:27,100
You bring in a tool.

390
00:18:27,100 --> 00:18:29,560
And the material is
spinning in this case.

391
00:18:29,560 --> 00:18:32,170
And there's essentially
no stresses on it.

392
00:18:32,170 --> 00:18:34,300
Then you come in with a
tool and start applying

393
00:18:34,300 --> 00:18:37,390
a significant force over
a very limited area,

394
00:18:37,390 --> 00:18:40,000
in such a way as to create
a critical shear stress,

395
00:18:40,000 --> 00:18:45,040
and the material
decides to leave.

396
00:18:45,040 --> 00:18:48,370
And so in an abstract sense,
I can think of machining

397
00:18:48,370 --> 00:18:53,620
as locating a very concentrated
maximal shear stress

398
00:18:53,620 --> 00:18:56,620
point at different
places in such a way

399
00:18:56,620 --> 00:19:00,270
as to at that location make the
material disassociate with it.

400
00:19:04,827 --> 00:19:07,160
Yeah, so we already talked
about this one, heat transfer

401
00:19:07,160 --> 00:19:09,020
at the mold surface
and injection molding.

402
00:19:14,970 --> 00:19:20,743
So another extreme of
interaction to give you an idea

403
00:19:20,743 --> 00:19:22,410
that there's more
than one way to remove

404
00:19:22,410 --> 00:19:26,430
material, and certainly anybody
with a mechanical engineering

405
00:19:26,430 --> 00:19:29,630
education, any sort of shop
or manufacturing experience

406
00:19:29,630 --> 00:19:31,962
says, oh, yeah,
machining, that's it.

407
00:19:31,962 --> 00:19:33,420
And that's how you
remove material.

408
00:19:33,420 --> 00:19:36,210
But, of course,
we remove material

409
00:19:36,210 --> 00:19:38,070
in a lot of different ways.

410
00:19:38,070 --> 00:19:41,340
And, of course, anybody from a
EE or semiconductor background

411
00:19:41,340 --> 00:19:43,590
says, oh, yeah, removal,
that's chemical etching

412
00:19:43,590 --> 00:19:46,180
or something like that.

413
00:19:46,180 --> 00:19:47,160
And that's true also.

414
00:19:47,160 --> 00:19:50,370
But then you have many things,
these beam type processes,

415
00:19:50,370 --> 00:19:54,340
which are very important for
a lot of different processes.

416
00:19:54,340 --> 00:19:58,200
But think the extreme
case of a process where

417
00:19:58,200 --> 00:20:03,120
things are very localized and
you're just doing something

418
00:20:03,120 --> 00:20:05,628
in a very small region
and then you move

419
00:20:05,628 --> 00:20:06,795
that region around the part.

420
00:20:06,795 --> 00:20:09,720
It might be something
like laser processing,

421
00:20:09,720 --> 00:20:13,890
laser beams, using laser
beam to cut and moving it.

422
00:20:13,890 --> 00:20:18,008
This is meant to be a picture
of a robot moving it around.

423
00:20:18,008 --> 00:20:19,800
So the robot is very
important in this case

424
00:20:19,800 --> 00:20:22,740
because it's
providing the motion

425
00:20:22,740 --> 00:20:24,132
and moving the laser tool.

426
00:20:24,132 --> 00:20:25,590
And, of course,
this has been taken

427
00:20:25,590 --> 00:20:29,550
to extreme with these
femtosecond lasers, which

428
00:20:29,550 --> 00:20:34,080
can affect at any given instant,
will only ablate material

429
00:20:34,080 --> 00:20:37,560
and, I don't know
what, sub-micron areas.

430
00:20:37,560 --> 00:20:39,600
So you can really localize
it if you want to.

431
00:20:42,470 --> 00:20:45,580
And then you've got you've
got other things like this,

432
00:20:45,580 --> 00:20:48,460
like a CVD process where
what you're actually doing

433
00:20:48,460 --> 00:20:53,560
is locating a chemical reaction
across the entire surface

434
00:20:53,560 --> 00:20:55,070
of something.

435
00:20:55,070 --> 00:20:59,650
And again, that location
is determined primarily

436
00:20:59,650 --> 00:21:03,520
by whatever substrate it
is you're trying to coat.

437
00:21:03,520 --> 00:21:07,660
In this case, we're
trying to coat.

438
00:21:07,660 --> 00:21:13,600
But just to throw this out,
if I have a nice clean uniform

439
00:21:13,600 --> 00:21:15,100
substrate, even with--

440
00:21:15,100 --> 00:21:17,530
well, let's just take a
flat one, a flat disk,

441
00:21:17,530 --> 00:21:20,370
and I need to coat it with
a chemical vapor deposition

442
00:21:20,370 --> 00:21:20,870
process.

443
00:21:20,870 --> 00:21:26,350
So I've got this vapor, and it's
going to deposit and solidify

444
00:21:26,350 --> 00:21:28,780
on the surface.

445
00:21:28,780 --> 00:21:32,363
What's going to determine the
final geometry of that surface,

446
00:21:32,363 --> 00:21:33,655
of that coating of the surface?

447
00:21:37,520 --> 00:21:42,200
AUDIENCE: [INAUDIBLE]

448
00:21:42,200 --> 00:21:43,700
DAVID HARDT: Yeah,
well let's assume

449
00:21:43,700 --> 00:21:48,590
this is just sort of this
chamber filled with the vapor

450
00:21:48,590 --> 00:21:51,900
and then you introduce
this in there.

451
00:21:51,900 --> 00:21:52,400
OK?

452
00:21:52,400 --> 00:21:53,530
AUDIENCE: Time.

453
00:21:53,530 --> 00:21:57,178
DAVID HARDT: Time certainly
is a big part of it, yeah.

454
00:21:57,178 --> 00:21:58,041
AUDIENCE: Topology.

455
00:22:00,690 --> 00:22:03,780
DAVID HARDT: The topology
of the substrate.

456
00:22:03,780 --> 00:22:06,123
And I'll just throw
in the other is that--

457
00:22:06,123 --> 00:22:08,040
because I want to make
the point that with any

458
00:22:08,040 --> 00:22:12,420
of these processes that
occur with a distribution

459
00:22:12,420 --> 00:22:16,110
sort of simultaneously, the ones
that Simon was talking about

460
00:22:16,110 --> 00:22:21,090
earlier, there's
always this concern

461
00:22:21,090 --> 00:22:23,525
that you don't have uniform
spatial distribution.

462
00:22:23,525 --> 00:22:24,900
So what I was
getting at is there

463
00:22:24,900 --> 00:22:29,483
was no intention of having
directed vapor density

464
00:22:29,483 --> 00:22:30,400
or anything like that.

465
00:22:30,400 --> 00:22:35,820
The idea is I've got this
uniform cloud of vapor.

466
00:22:35,820 --> 00:22:37,440
And it's reacting
with the surface.

467
00:22:37,440 --> 00:22:40,890
So why might it vary spatially?

468
00:22:40,890 --> 00:22:42,540
It's certainly going
to vary over time,

469
00:22:42,540 --> 00:22:44,917
because it takes time for
this stuff to solidify.

470
00:22:44,917 --> 00:22:46,500
But it's also going
to vary spatially,

471
00:22:46,500 --> 00:22:48,997
because who said it's uniform?

472
00:22:48,997 --> 00:22:51,330
And one of the things you
want to think about when we're

473
00:22:51,330 --> 00:22:53,250
talking about manufacturing
is always sort of

474
00:22:53,250 --> 00:22:58,260
question any statement of
uniformity or constancy

475
00:22:58,260 --> 00:23:04,050
or things like that,
because inevitably there

476
00:23:04,050 --> 00:23:09,150
will be variations because the
topography of the substrate

477
00:23:09,150 --> 00:23:10,750
might change.

478
00:23:10,750 --> 00:23:11,430
Who knows?

479
00:23:11,430 --> 00:23:14,490
And in fact, it does
happen, especially

480
00:23:14,490 --> 00:23:16,200
as you go to larger
and larger wafers.

481
00:23:16,200 --> 00:23:20,310
You'll get important variations
in the chamber, temperature

482
00:23:20,310 --> 00:23:21,240
variations.

483
00:23:21,240 --> 00:23:23,230
You could get
concentration variations.

484
00:23:23,230 --> 00:23:25,905
All these kinds of things
can cause problems.

485
00:23:29,710 --> 00:23:31,410
One other that I'll
mention because I

486
00:23:31,410 --> 00:23:33,660
showed this piece of
sheet metal and talked

487
00:23:33,660 --> 00:23:37,170
about it as a concentrated
energy exchange.

488
00:23:37,170 --> 00:23:39,750
Here's another example of
a non-concentrated energy

489
00:23:39,750 --> 00:23:40,260
exchange.

490
00:23:40,260 --> 00:23:42,150
This is a large
piece of sheet metal.

491
00:23:42,150 --> 00:23:46,680
This dimension here is about 6
feet, aerospace manufacturing.

492
00:23:46,680 --> 00:23:51,405
And it's being pulled across
this tool and deformed in here.

493
00:23:51,405 --> 00:23:54,540
I actually have a sort of video
of this which I couldn't find.

494
00:23:54,540 --> 00:23:56,787
But you can see it being
pulled down to the tool.

495
00:23:56,787 --> 00:23:58,620
And because of the
reflections of the light,

496
00:23:58,620 --> 00:24:01,500
you can see that there's
not a single portion

497
00:24:01,500 --> 00:24:05,640
of this large piece of
metal that isn't being

498
00:24:05,640 --> 00:24:07,420
changed at any instant in time.

499
00:24:07,420 --> 00:24:10,530
So clearly, this is everything
happening everywhere

500
00:24:10,530 --> 00:24:12,070
all at once.

501
00:24:12,070 --> 00:24:16,900
And in effect we're pulling
it across a shaped tool.

502
00:24:16,900 --> 00:24:19,860
So in the end, we're imposing
this displacement field on it.

503
00:24:22,710 --> 00:24:26,310
So this gets us to this
concept of the taxonomy.

504
00:24:26,310 --> 00:24:27,840
You can see that--

505
00:24:27,840 --> 00:24:30,780
I've been kind of ranging
widely over a number

506
00:24:30,780 --> 00:24:35,820
of different processes, either
directly or by implication.

507
00:24:35,820 --> 00:24:39,010
And we want to kind of draw
some conclusions from this.

508
00:24:39,010 --> 00:24:41,430
So the first is that
there are two extremes

509
00:24:41,430 --> 00:24:45,750
to these interactions, the
so-called serial interaction.

510
00:24:45,750 --> 00:24:48,330
And schematically here
it's best described

511
00:24:48,330 --> 00:24:54,420
as my femtosecond laser,
infinitesimally small area

512
00:24:54,420 --> 00:24:58,210
of interaction over
the large area.

513
00:24:58,210 --> 00:25:00,000
So that at any instant
I'm only affecting

514
00:25:00,000 --> 00:25:03,240
a small part of the material.

515
00:25:03,240 --> 00:25:05,250
But then I move it.

516
00:25:05,250 --> 00:25:07,330
I have a time history of this.

517
00:25:07,330 --> 00:25:09,910
And that's what
determines the geometry.

518
00:25:09,910 --> 00:25:11,530
Now, of course,
in a real process,

519
00:25:11,530 --> 00:25:15,210
even with the femtosecond laser,
if you get to small enough,

520
00:25:15,210 --> 00:25:17,730
there are spatially
distributed effects.

521
00:25:17,730 --> 00:25:20,550
And as I go to larger
and larger tools,

522
00:25:20,550 --> 00:25:23,870
this gets worse and worse.

523
00:25:23,870 --> 00:25:27,100
But if we make a definition
that the area of the interaction

524
00:25:27,100 --> 00:25:29,890
of the energy
interaction is small

525
00:25:29,890 --> 00:25:33,710
compared to the total area
that I want to change,

526
00:25:33,710 --> 00:25:36,970
then it's clearly what
we'll call a serial process.

527
00:25:39,620 --> 00:25:44,270
If the opposite is true, if
the area of that interaction

528
00:25:44,270 --> 00:25:46,460
is on the order
of the total area

529
00:25:46,460 --> 00:25:48,110
that I'm trying to change--

530
00:25:48,110 --> 00:25:51,350
and again, the icon for that
would be stamping out a car

531
00:25:51,350 --> 00:25:52,790
hood or something like that--

532
00:25:52,790 --> 00:25:57,377
the area of interaction
is the same as the area

533
00:25:57,377 --> 00:25:58,460
that I'm trying to change.

534
00:25:58,460 --> 00:26:02,850
Same with this part, the area of
interaction is the entire area.

535
00:26:02,850 --> 00:26:06,110
Then we have a parallel process.

536
00:26:06,110 --> 00:26:11,870
We run into a couple of
interesting variants on that.

537
00:26:11,870 --> 00:26:19,670
If we take a very
common process, rolling,

538
00:26:19,670 --> 00:26:27,800
to create sheet or
just plate reductions--

539
00:26:27,800 --> 00:26:30,740
I'm coming in with material
that looks like this.

540
00:26:30,740 --> 00:26:32,960
I'm coming out with a
material that's much thinner.

541
00:26:46,000 --> 00:26:47,912
Where does this fit
in this taxonomy here,

542
00:26:47,912 --> 00:26:48,995
this part of the taxonomy?

543
00:26:48,995 --> 00:26:52,685
Is it a serial process
or a parallel process?

544
00:26:55,360 --> 00:26:57,240
AUDIENCE: Serial.

545
00:26:57,240 --> 00:26:58,480
DAVID HARDT: Serial.

546
00:26:58,480 --> 00:26:58,980
OK.

547
00:27:02,250 --> 00:27:04,500
OK, so we have 50%
of the electorate

548
00:27:04,500 --> 00:27:09,240
going for serial in this
mostly democratic primary.

549
00:27:09,240 --> 00:27:10,200
Parallel?

550
00:27:10,200 --> 00:27:12,630
50% saying parallel.

551
00:27:12,630 --> 00:27:14,787
I guess it goes to
the super-delegates.

552
00:27:18,130 --> 00:27:21,470
OK, you guys in
Singapore and to you,

553
00:27:21,470 --> 00:27:23,445
you guys, you want to
break the tie here?

554
00:27:23,445 --> 00:27:24,010
What is it?

555
00:27:24,010 --> 00:27:26,260
Is it serial or parallel?

556
00:27:26,260 --> 00:27:28,270
AUDIENCE: I think it's parallel.

557
00:27:28,270 --> 00:27:31,630
DAVID HARDT: OK, so
51% for parallel.

558
00:27:31,630 --> 00:27:33,460
Anybody there say serial?

559
00:27:39,760 --> 00:27:43,248
Yeah, we got some serials here.

560
00:27:43,248 --> 00:27:44,740
AUDIENCE: It depends
on the light.

561
00:27:44,740 --> 00:27:46,720
DAVID HARDT: Yeah.

562
00:27:46,720 --> 00:27:48,020
Yeah, now, we're getting to it.

563
00:27:48,020 --> 00:27:50,020
OK, it depends.

564
00:27:50,020 --> 00:27:56,030
If I had drawn this
in 2D like this

565
00:27:56,030 --> 00:28:00,260
and maybe sort of
drawn it in extreme

566
00:28:00,260 --> 00:28:01,730
and didn't even
show this necking,

567
00:28:01,730 --> 00:28:04,970
just kind of showed
it doing this,

568
00:28:04,970 --> 00:28:07,370
then you'd be pretty
tempted to say,

569
00:28:07,370 --> 00:28:09,620
oh, that's a serial process,
because all the action is

570
00:28:09,620 --> 00:28:10,190
right here.

571
00:28:10,190 --> 00:28:12,050
Look at this huge area
that I'm affecting

572
00:28:12,050 --> 00:28:14,330
and all the action
is right there.

573
00:28:14,330 --> 00:28:26,630
If I had drawn it in a front end
view and here's the material,

574
00:28:26,630 --> 00:28:29,000
you look at that, and
say, oh, that's parallel.

575
00:28:29,000 --> 00:28:33,710
Everything's happening
everywhere at the same time.

576
00:28:33,710 --> 00:28:38,870
So just a cautionary
tale, it's not either

577
00:28:38,870 --> 00:28:42,200
or, it's neither nor.

578
00:28:42,200 --> 00:28:44,890
It's sort of preponderance
of, if you will.

579
00:28:47,450 --> 00:28:52,190
So this is a good example of
why they're actually important,

580
00:28:52,190 --> 00:28:54,320
even though it's mixed on here.

581
00:28:54,320 --> 00:28:57,110
And I'm going to jump ahead
to the sort of who cares,

582
00:28:57,110 --> 00:29:00,530
which may not have a
satisfactory answer today.

583
00:29:00,530 --> 00:29:06,030
But the who cares is if
I'm running, in this case,

584
00:29:06,030 --> 00:29:08,720
the Alcoa Tennessee--
that's a real town--

585
00:29:08,720 --> 00:29:11,600
the Alcoa, Tennessee,
cold rolling

586
00:29:11,600 --> 00:29:15,590
mill that makes all
their beer cans stock,

587
00:29:15,590 --> 00:29:19,520
and I'm really concerned
about extremely good thickness

588
00:29:19,520 --> 00:29:22,130
control, because when it goes
into the high speed canning

589
00:29:22,130 --> 00:29:24,290
machines that thickness
has to be right on.

590
00:29:24,290 --> 00:29:29,310
Otherwise, the walls will tear
or it won't form properly.

591
00:29:29,310 --> 00:29:31,040
What do I control?

592
00:29:31,040 --> 00:29:35,270
Just intuitively, what would I
control to affect the geometry

593
00:29:35,270 --> 00:29:37,988
parameter called the thickness?

594
00:29:37,988 --> 00:29:39,300
AUDIENCE: Distance.

595
00:29:39,300 --> 00:29:41,940
DAVID HARDT: Distance
between the rolls, yeah.

596
00:29:41,940 --> 00:29:45,120
So I control the
thickness by controlling,

597
00:29:45,120 --> 00:29:47,670
let's say, this
distance right here.

598
00:29:51,580 --> 00:29:54,910
Which thickness
does that control?

599
00:29:54,910 --> 00:29:58,750
Does it control this
thickness right here,

600
00:29:58,750 --> 00:30:04,930
or this one here, or that one
there, or maybe that one there,

601
00:30:04,930 --> 00:30:05,800
or that one there?

602
00:30:09,480 --> 00:30:11,420
Yeah, all you're doing--

603
00:30:11,420 --> 00:30:14,240
there's one spacing area.

604
00:30:14,240 --> 00:30:17,570
And if you say, oh, yeah,
it's exactly right here.

605
00:30:17,570 --> 00:30:20,210
And then I make little
disks and make my cans

606
00:30:20,210 --> 00:30:22,190
with the material
over here, who's

607
00:30:22,190 --> 00:30:24,690
to say it's going to be right?

608
00:30:24,690 --> 00:30:27,090
So even in this
case, I've actually

609
00:30:27,090 --> 00:30:30,470
got a mixed problem here
and a mixed control problem.

610
00:30:30,470 --> 00:30:33,690
So, yeah, here's a case
where displacement--

611
00:30:33,690 --> 00:30:37,353
this trajectory we're talking
about, just like this deal,

612
00:30:37,353 --> 00:30:38,770
you want to think
of it that way--

613
00:30:38,770 --> 00:30:44,230
I'm directing the energy
source by displacing it.

614
00:30:44,230 --> 00:30:45,940
That's part of it.

615
00:30:45,940 --> 00:30:52,390
But then how do I change
the thickness distribution,

616
00:30:52,390 --> 00:30:54,730
the parallel part
of the process?

617
00:30:54,730 --> 00:30:57,040
Well, I'd actually
probably have to change

618
00:30:57,040 --> 00:30:59,920
the shape of the rolls.

619
00:30:59,920 --> 00:31:00,970
You do a little bit.

620
00:31:00,970 --> 00:31:02,290
They actually do both sides.

621
00:31:02,290 --> 00:31:04,030
And that does help.

622
00:31:04,030 --> 00:31:05,360
But let's say I do both sides.

623
00:31:05,360 --> 00:31:06,593
So this is exactly right.

624
00:31:06,593 --> 00:31:07,510
This is exactly right.

625
00:31:07,510 --> 00:31:10,660
And the middle looks like
this, which is not uncommon.

626
00:31:10,660 --> 00:31:13,635
It becomes fatter in the middle.

627
00:31:13,635 --> 00:31:14,260
What do you do?

628
00:31:17,760 --> 00:31:19,192
AUDIENCE: Change the rolls.

629
00:31:19,192 --> 00:31:21,150
DAVID HARDT: Yeah, but
I don't want to do that.

630
00:31:21,150 --> 00:31:22,410
Yes, you would change the rolls.

631
00:31:22,410 --> 00:31:24,327
And, in fact, what they
do is they build roles

632
00:31:24,327 --> 00:31:25,890
with a little bit
of camber in them.

633
00:31:25,890 --> 00:31:27,390
Because you know
the center is going

634
00:31:27,390 --> 00:31:28,515
to deflect up a little bit.

635
00:31:28,515 --> 00:31:30,600
So you put some camber into it.

636
00:31:30,600 --> 00:31:33,450
Believe it or not at Alcoa,
that's still not good enough.

637
00:31:33,450 --> 00:31:35,490
This stuff is very precise.

638
00:31:35,490 --> 00:31:37,440
I shouldn't quote
the tolerances.

639
00:31:37,440 --> 00:31:42,330
But it's on the order of in
my newly converted SI brain,

640
00:31:42,330 --> 00:31:47,800
I think it could be 15 microns.

641
00:31:47,800 --> 00:31:53,710
It could be in the 10,000th,
several 10,000th of inch

642
00:31:53,710 --> 00:31:55,750
in terms of thickness tolerance.

643
00:31:55,750 --> 00:31:57,480
It's not very thick
stuff to begin with.

644
00:31:57,480 --> 00:32:00,830
AUDIENCE: It would be like
locally heated through--

645
00:32:00,830 --> 00:32:03,080
DAVID HARDT: Yeah, in
fact, that's what is done.

646
00:32:03,080 --> 00:32:05,920
To get small displacements,
to be able to actually

647
00:32:05,920 --> 00:32:07,270
arbitrarily--

648
00:32:07,270 --> 00:32:10,540
not arbitrarily-- but to
put some different profiles

649
00:32:10,540 --> 00:32:14,910
on that, you'll locally heat
it or cool it in response

650
00:32:14,910 --> 00:32:17,670
to the feedback to
actually slowly move

651
00:32:17,670 --> 00:32:19,285
the tool locally a
little bit fatter

652
00:32:19,285 --> 00:32:20,660
here and a little
bit less there.

653
00:32:20,660 --> 00:32:23,100
You can imagine if you
only need 10 microns,

654
00:32:23,100 --> 00:32:26,070
something like that, it
doesn't take a lot of heat.

655
00:32:26,070 --> 00:32:27,810
And, yes, indeed you're
going to say, oh,

656
00:32:27,810 --> 00:32:29,130
how localized can that be?

657
00:32:29,130 --> 00:32:33,270
And that's the trade secret they
won't tell anybody about but.

658
00:32:33,270 --> 00:32:36,150
Yeah, so in this
particular case,

659
00:32:36,150 --> 00:32:43,503
notice these two different modes
of modes of interaction lead

660
00:32:43,503 --> 00:32:45,170
to two different ways
of controlling it.

661
00:32:45,170 --> 00:32:47,240
In one case, it's very simple.

662
00:32:47,240 --> 00:32:48,702
I'm going to buy a Servo system.

663
00:32:48,702 --> 00:32:49,910
It's going to be really good.

664
00:32:49,910 --> 00:32:51,077
It's going to be very stiff.

665
00:32:51,077 --> 00:32:55,280
And I'm going to say, make that
2/1,000 inch gap and you get

666
00:32:55,280 --> 00:32:56,930
2/1,000 inch gap.

667
00:32:56,930 --> 00:33:00,050
In the other case, it's
like, oh, my gosh, you know,

668
00:33:00,050 --> 00:33:03,920
I've got to change this
spatial distribution somehow.

669
00:33:03,920 --> 00:33:05,720
The extreme case is to
shut the thing down,

670
00:33:05,720 --> 00:33:08,010
put in a new set of roles.

671
00:33:08,010 --> 00:33:10,260
And the other is to come
up with some clever way

672
00:33:10,260 --> 00:33:12,660
of deforming it.

673
00:33:12,660 --> 00:33:15,480
So why do we worry about the
two modes of interaction?

674
00:33:15,480 --> 00:33:18,780
It leads directly
to how we would ever

675
00:33:18,780 --> 00:33:22,410
find the knobs on the machine
to change what we're doing.

676
00:33:22,410 --> 00:33:25,070
Now, that will
become most important

677
00:33:25,070 --> 00:33:26,820
in the last part of
the class when we talk

678
00:33:26,820 --> 00:33:28,200
about process optimization.

679
00:33:28,200 --> 00:33:31,057
And you're saying,
what can I do?

680
00:33:31,057 --> 00:33:32,640
What can actually
change on a process?

681
00:33:32,640 --> 00:33:37,860
What can I change real
time, millisecond?

682
00:33:37,860 --> 00:33:40,050
What can I change, maybe--

683
00:33:40,050 --> 00:33:43,200
in this case, this is an
unusual example-- what can I

684
00:33:43,200 --> 00:33:46,660
change on a frequent basis?

685
00:33:46,660 --> 00:33:48,163
But in most cases,
the major change

686
00:33:48,163 --> 00:33:49,830
you do with tooling
and things like this

687
00:33:49,830 --> 00:33:55,510
is on hourly shift,
yearly basis.

688
00:33:55,510 --> 00:33:57,420
So your ability to
affect the output

689
00:33:57,420 --> 00:34:00,900
once you've kind of
literally cast it in stone

690
00:34:00,900 --> 00:34:03,690
is greatly changed
by whether it's

691
00:34:03,690 --> 00:34:05,790
a parallel or serial process.

692
00:34:14,570 --> 00:34:17,330
OK, so just to
summarize this again,

693
00:34:17,330 --> 00:34:21,760
so for this lumped
or serial case,

694
00:34:21,760 --> 00:34:24,010
the time trajectory of
that interaction port

695
00:34:24,010 --> 00:34:25,550
is one of the most
important things.

696
00:34:25,550 --> 00:34:29,500
So robotic manufacturing,
which was all the rage for many

697
00:34:29,500 --> 00:34:32,050
a year, until we found
out it wasn't really

698
00:34:32,050 --> 00:34:36,159
such a thing to
be rageful about,

699
00:34:36,159 --> 00:34:40,929
it works for a limited class
of processes pretty well.

700
00:34:40,929 --> 00:34:45,310
And your classic CNC
machine, the CNC machine

701
00:34:45,310 --> 00:34:48,580
of the '60s, which sort of
got generalized in the '70s

702
00:34:48,580 --> 00:34:50,895
and put everywhere,
essentially means

703
00:34:50,895 --> 00:34:53,020
if you want to put in the
terminology of what we're

704
00:34:53,020 --> 00:34:56,050
talking about today
usually means the ability

705
00:34:56,050 --> 00:35:00,010
to control trajectories
in a very repeatable way.

706
00:35:00,010 --> 00:35:03,820
So it's not just a machine
that can follow a trajectory,

707
00:35:03,820 --> 00:35:05,890
it's also the ability to
generate the trajectory

708
00:35:05,890 --> 00:35:07,490
and things like that.

709
00:35:07,490 --> 00:35:09,250
And then in this distributed--

710
00:35:09,250 --> 00:35:11,440
I've used two different
terms here-- but distributed

711
00:35:11,440 --> 00:35:15,040
or parallel case,
more than anything,

712
00:35:15,040 --> 00:35:17,470
it's the shape of the energy
distributor, you know,

713
00:35:17,470 --> 00:35:21,082
patterns, molds, masks,
heat distributions,

714
00:35:21,082 --> 00:35:21,790
things like that.

715
00:35:24,310 --> 00:35:25,900
I think we've seen
enough examples.

716
00:35:25,900 --> 00:35:28,630
We're sick of these now.

717
00:35:28,630 --> 00:35:31,090
Oh, yeah, well, you'll
see this in a moment,

718
00:35:31,090 --> 00:35:35,440
but a lot of the so-called
rapid prototyping

719
00:35:35,440 --> 00:35:39,310
methods that popped up in
the '90s, or solid free form

720
00:35:39,310 --> 00:35:43,930
fabrication as the
government likes to call it,

721
00:35:43,930 --> 00:35:47,050
stereolithography, sort of
the first big one on that 3D

722
00:35:47,050 --> 00:35:52,100
printing and developed
here, are serial processes.

723
00:35:52,100 --> 00:35:55,370
And they figured out
how to put down--

724
00:35:55,370 --> 00:35:57,950
they turn out to be usually
serial addition type

725
00:35:57,950 --> 00:35:59,090
processes--

726
00:35:59,090 --> 00:36:00,770
figured out how to
put a dot of material

727
00:36:00,770 --> 00:36:05,870
down at a time to
build up a structure.

728
00:36:05,870 --> 00:36:09,800
And that dot itself was cohesive
enough that if you put it down,

729
00:36:09,800 --> 00:36:12,350
it stayed there and you didn't
need anything to hold it.

730
00:36:15,890 --> 00:36:18,090
And I'll talk more about
that in just a moment.

731
00:36:18,090 --> 00:36:22,130
But I think we've kind of
talked about-- these are all

732
00:36:22,130 --> 00:36:23,220
interesting examples.

733
00:36:23,220 --> 00:36:28,760
So if we talk about a taxonomy
to kind of bring together

734
00:36:28,760 --> 00:36:36,200
the energy source, if you
will, for the geometry

735
00:36:36,200 --> 00:36:41,700
change, the way we apply it,
and a couple other things that

736
00:36:41,700 --> 00:36:44,660
will come up in just a
second, then we can--

737
00:36:44,660 --> 00:36:49,655
and I think I've said why for
the mode, the change mode--

738
00:36:49,655 --> 00:36:50,870
oh, actually I haven't.

739
00:36:50,870 --> 00:36:52,640
I'm sorry about that.

740
00:36:52,640 --> 00:36:54,710
Why does it matter--

741
00:36:54,710 --> 00:36:56,360
let me go back to this.

742
00:36:56,360 --> 00:36:58,910
I think I won't bother
with the slides.

743
00:36:58,910 --> 00:37:03,560
What I called mode before
was really my energy source.

744
00:37:03,560 --> 00:37:11,750
Why does it matter whether I'm
using mechanical, electrical,

745
00:37:11,750 --> 00:37:16,400
thermal, or chemical
as my change agent?

746
00:37:19,940 --> 00:37:23,690
What difference does that make?

747
00:37:23,690 --> 00:37:24,760
It's just energy, right?

748
00:37:30,530 --> 00:37:33,650
And again, back to lecture
1, what do we care about

749
00:37:33,650 --> 00:37:34,400
in the process?

750
00:37:34,400 --> 00:37:37,560
Quality, number
one in this class.

751
00:37:37,560 --> 00:37:39,710
But also we worry about rate.

752
00:37:39,710 --> 00:37:42,110
And we worry about cost.

753
00:37:42,110 --> 00:37:45,990
And we worry about flexibility.

754
00:37:45,990 --> 00:37:53,890
So with respect to which
energy mode is involved,

755
00:37:53,890 --> 00:37:58,860
what difference does it
make in this consideration?

756
00:37:58,860 --> 00:37:59,530
Simon.

757
00:37:59,530 --> 00:38:01,780
AUDIENCE: Well, in the way
we can control the process,

758
00:38:01,780 --> 00:38:04,100
we need to know what
[? eventually ?] is involved,

759
00:38:04,100 --> 00:38:06,017
so we can change the
[? size ?] of the energy.

760
00:38:06,017 --> 00:38:07,900
DAVID HARDT: Yeah,
sure, absolutely,

761
00:38:07,900 --> 00:38:09,715
so I would control
these in different ways.

762
00:38:12,670 --> 00:38:14,260
But let's assume
I could do that.

763
00:38:14,260 --> 00:38:16,540
I know how to control
mechanical energy.

764
00:38:16,540 --> 00:38:19,060
I can change forces and
displacements and velocities,

765
00:38:19,060 --> 00:38:22,540
electrical currents
and voltages.

766
00:38:22,540 --> 00:38:25,360
Thermal, that's a
little bit different.

767
00:38:25,360 --> 00:38:27,760
I can certainly
control temperatures.

768
00:38:27,760 --> 00:38:30,190
I can also try to control
their distributions.

769
00:38:30,190 --> 00:38:33,490
I can sometimes control-- heat
flux is a little bit harder

770
00:38:33,490 --> 00:38:34,450
to do.

771
00:38:34,450 --> 00:38:37,450
And chemical, I can control
concentrations and temperatures

772
00:38:37,450 --> 00:38:40,090
and maybe reaction rates
as a result of that.

773
00:38:40,090 --> 00:38:40,825
Yeah.

774
00:38:40,825 --> 00:38:43,250
AUDIENCE: [INAUDIBLE]
if you're affecting

775
00:38:43,250 --> 00:38:47,592
a large area or smaller
wafer versus a big stack of

776
00:38:47,592 --> 00:38:48,960
[INAUDIBLE]

777
00:38:48,960 --> 00:38:52,588
DAVID HARDT: Yeah,
I thought you were

778
00:38:52,588 --> 00:38:53,880
going someplace else with that.

779
00:38:53,880 --> 00:38:56,610
But, yes, there
is a size scaling.

780
00:38:56,610 --> 00:38:59,250
But the example you
gave actually, though,

781
00:38:59,250 --> 00:39:04,590
a wafer, in terms of the
relative size of the features

782
00:39:04,590 --> 00:39:07,855
that I care about
is actually huge

783
00:39:07,855 --> 00:39:09,510
when you think about
a wafer compared

784
00:39:09,510 --> 00:39:12,510
to a tiny little
sub-micron line,

785
00:39:12,510 --> 00:39:13,920
and then I think
about a car hood

786
00:39:13,920 --> 00:39:17,400
with a little feature
in the middle,

787
00:39:17,400 --> 00:39:20,130
the wafer is actually bigger.

788
00:39:20,130 --> 00:39:24,040
AUDIENCE: I was thinking of the
[INAUDIBLE] with the changes

789
00:39:24,040 --> 00:39:24,540
in--

790
00:39:24,540 --> 00:39:25,040
I mean--

791
00:39:25,040 --> 00:39:26,920
DAVID HARDT: Yeah, yeah, yeah.

792
00:39:26,920 --> 00:39:30,305
OK, I think you're getting
to what I wanted to do.

793
00:39:30,305 --> 00:39:32,680
Let me see if I can get any
more here and then we'll see.

794
00:39:32,680 --> 00:39:33,410
Yeah, [? Kimmy. ?]

795
00:39:33,410 --> 00:39:34,827
AUDIENCE: The rates
are definitely

796
00:39:34,827 --> 00:39:37,436
change of [INAUDIBLE] mechanical
is usually faster than

797
00:39:37,436 --> 00:39:38,930
[INAUDIBLE]

798
00:39:38,930 --> 00:39:40,890
DAVID HARDT: Yeah,
yeah, believe it or not,

799
00:39:40,890 --> 00:39:43,370
when you think about this, you
always think of electrical,

800
00:39:43,370 --> 00:39:46,040
oh, that's the gigahertz range,
and all that kind of stuff.

801
00:39:46,040 --> 00:39:48,860
And that's true if all you
need to do is move electrons.

802
00:39:48,860 --> 00:39:50,910
But we have to move
material around here.

803
00:39:50,910 --> 00:39:54,200
So this tends to be very fast.

804
00:39:54,200 --> 00:39:58,470
If I apply a mechanical
load to something,

805
00:39:58,470 --> 00:40:02,820
I can modulate that load pretty
fast these days if I want to.

806
00:40:02,820 --> 00:40:08,550
And when I bring a tool
into a piece of sheet metal

807
00:40:08,550 --> 00:40:12,263
like this, how long does
it take for this to react?

808
00:40:12,263 --> 00:40:14,180
Well, essentially, at
the kinds of time scales

809
00:40:14,180 --> 00:40:16,790
we're talking about it, it
happens instantaneously.

810
00:40:16,790 --> 00:40:19,940
Compare that to how long
it takes to etch something

811
00:40:19,940 --> 00:40:21,950
or do certain
deposition processes.

812
00:40:21,950 --> 00:40:25,790
We're doing these nickel
plated micron scale tools.

813
00:40:25,790 --> 00:40:27,650
I just saw a
presentation last night,

814
00:40:27,650 --> 00:40:33,290
three days to make a tool
with 50 micron features on it.

815
00:40:33,290 --> 00:40:36,530
That's not what
you'd call smoking.

816
00:40:36,530 --> 00:40:38,400
So pretty low stuff.

817
00:40:38,400 --> 00:40:40,807
So rate-- we can argue
different things.

818
00:40:40,807 --> 00:40:43,140
You can have fast chemical
stuff and so forth and so on.

819
00:40:43,140 --> 00:40:46,530
But in general, there's
a speed issue here.

820
00:40:46,530 --> 00:40:47,030
What else?

821
00:40:53,360 --> 00:40:54,000
That's rate.

822
00:40:54,000 --> 00:40:56,666
What about quality?

823
00:40:56,666 --> 00:40:59,175
AUDIENCE: There are also
side effects of the process.

824
00:40:59,175 --> 00:41:00,508
DAVID HARDT: Yeah, side effects.

825
00:41:00,508 --> 00:41:01,090
I like that.

826
00:41:01,090 --> 00:41:02,950
Say a little bit more
about side effects.

827
00:41:02,950 --> 00:41:04,300
AUDIENCE: Well, you
got the theoretical.

828
00:41:04,300 --> 00:41:05,850
Maybe I want to cut
a perfect square.

829
00:41:05,850 --> 00:41:08,860
But the tool is not going
cut perfectly square edges.

830
00:41:08,860 --> 00:41:10,990
So depending on
what process I use,

831
00:41:10,990 --> 00:41:13,260
it may have undercutting
or rounded edges.

832
00:41:13,260 --> 00:41:14,260
DAVID HARDT: Absolutely.

833
00:41:14,260 --> 00:41:14,960
Absolutely.

834
00:41:14,960 --> 00:41:18,850
So there's something
here inherently related

835
00:41:18,850 --> 00:41:22,180
to quality, at least two
things that I can think of.

836
00:41:22,180 --> 00:41:27,700
One of them is related to
what I'll call diffusivity

837
00:41:27,700 --> 00:41:31,120
in the general sense, not just
purely in the thermal sense.

838
00:41:31,120 --> 00:41:35,455
If I apply a load to
something, as you're

839
00:41:35,455 --> 00:41:37,830
saying, if I apply a load to
something, even with a point

840
00:41:37,830 --> 00:41:40,412
tool, there's a stress
field that develops in it

841
00:41:40,412 --> 00:41:41,370
and that sort of thing.

842
00:41:41,370 --> 00:41:43,490
And this will be a
little bit facile,

843
00:41:43,490 --> 00:41:46,130
but I can make an argument
that says, OK, if I apply

844
00:41:46,130 --> 00:41:48,290
that load to here, it diffuses.

845
00:41:48,290 --> 00:41:52,375
And so I wanted to put
the load in a tiny point,

846
00:41:52,375 --> 00:41:53,750
but it actually
spread out and so

847
00:41:53,750 --> 00:41:55,130
I didn't get
exactly what I want.

848
00:41:55,130 --> 00:41:57,560
How about if I put a
thermal source in there?

849
00:42:00,920 --> 00:42:03,510
And the worst part is not
only does it dissipate,

850
00:42:03,510 --> 00:42:05,100
it just keeps dissipating.

851
00:42:05,100 --> 00:42:06,630
Probably never
reaches equilibrium.

852
00:42:06,630 --> 00:42:07,580
So it's really going.

853
00:42:07,580 --> 00:42:11,120
How about a chemical reaction?

854
00:42:13,998 --> 00:42:16,040
One of the problems we
have with that, of course,

855
00:42:16,040 --> 00:42:18,700
is if you do thick etching, you
have undercutting, because it--

856
00:42:18,700 --> 00:42:19,520
don't go there.

857
00:42:19,520 --> 00:42:20,440
But it's going there.

858
00:42:20,440 --> 00:42:23,240
It wants to go everywhere
and other things like that.

859
00:42:23,240 --> 00:42:27,010
So, again, you have different
diffusion characteristics here,

860
00:42:27,010 --> 00:42:29,060
depending on what's going on.

861
00:42:29,060 --> 00:42:31,810
So your ability to
control the shape,

862
00:42:31,810 --> 00:42:34,750
to get a minimum feature size,
to get a level of precision,

863
00:42:34,750 --> 00:42:39,370
will vary depending
on what you have here.

864
00:42:39,370 --> 00:42:44,080
And what else do you think
is important to quality?

865
00:42:44,080 --> 00:42:48,730
Obviously, my ability
to sort of direct things

866
00:42:48,730 --> 00:42:51,050
exactly where I want
them to be is important.

867
00:42:51,050 --> 00:42:53,500
What else do you think
is important to quality?

868
00:42:53,500 --> 00:42:56,890
AUDIENCE: How about
repeatability?

869
00:42:56,890 --> 00:43:03,000
DAVID HARDT: Yeah, sort of
the how well I can repeatedly

870
00:43:03,000 --> 00:43:06,120
apply this energy and have
the same thing happen.

871
00:43:06,120 --> 00:43:09,990
And that will vary again,
depending on the nature

872
00:43:09,990 --> 00:43:11,130
of the interfaces here.

873
00:43:11,130 --> 00:43:15,570
For example, if
thermal conductivity

874
00:43:15,570 --> 00:43:18,570
is a big part of it
and you're continually

875
00:43:18,570 --> 00:43:20,998
bringing new material into
contact with an old tool,

876
00:43:20,998 --> 00:43:23,040
it could be a different
heat transfer coefficient

877
00:43:23,040 --> 00:43:25,260
every time.

878
00:43:25,260 --> 00:43:26,940
In mechanical
cases, if I'm always

879
00:43:26,940 --> 00:43:30,390
coming back with the same tool,
except for long term where,

880
00:43:30,390 --> 00:43:34,742
maybe it's a little
bit more repeatable.

881
00:43:38,120 --> 00:43:39,760
There's one other
aspect to it now.

882
00:43:39,760 --> 00:43:42,470
Now, think a little
bit more about where

883
00:43:42,470 --> 00:43:44,090
we're going with the
class with things

884
00:43:44,090 --> 00:43:46,610
like statistical process
control, which says,

885
00:43:46,610 --> 00:43:48,170
let's find out
things that are not

886
00:43:48,170 --> 00:43:50,480
quite right with the
process and fix them

887
00:43:50,480 --> 00:43:52,400
and that will
improve our quality.

888
00:43:52,400 --> 00:43:56,330
And then in the more
active process optimization

889
00:43:56,330 --> 00:43:58,520
stuff, where we say
let's adjust things

890
00:43:58,520 --> 00:43:59,780
until they're really right.

891
00:43:59,780 --> 00:44:01,340
And then actually
at the end, we'll

892
00:44:01,340 --> 00:44:03,215
talk a little bit about
active control, where

893
00:44:03,215 --> 00:44:05,430
you're continually adjusting.

894
00:44:05,430 --> 00:44:10,800
But think of it this way,
because you will be thinking

895
00:44:10,800 --> 00:44:12,930
about this, here's the process.

896
00:44:12,930 --> 00:44:16,990
I just measured its result.
It's not good enough.

897
00:44:16,990 --> 00:44:19,380
I need to improve its quality.

898
00:44:19,380 --> 00:44:21,480
And I can't go
buy a new machine.

899
00:44:25,380 --> 00:44:28,910
So I have to have the
ability to adjust something.

900
00:44:28,910 --> 00:44:31,175
I have to have the ability
to change something.

901
00:44:31,175 --> 00:44:33,050
So think about what it
takes to change these,

902
00:44:33,050 --> 00:44:38,330
just as I was saying before with
the rolling case in the-- yeah,

903
00:44:38,330 --> 00:44:39,680
go ahead.

904
00:44:39,680 --> 00:44:42,050
AUDIENCE: I think for
some mechanical processes,

905
00:44:42,050 --> 00:44:44,230
it's easier to stop.

906
00:44:44,230 --> 00:44:49,520
But for the chemical, thermal,
even if you know the problem,

907
00:44:49,520 --> 00:44:50,990
it can be hard to
stop the process.

908
00:44:50,990 --> 00:44:51,770
It's hard to stop.

909
00:44:51,770 --> 00:44:52,850
DAVID HARDT: Yeah.

910
00:44:52,850 --> 00:44:55,225
I mean, I'm not trying to come
up with winners and losers

911
00:44:55,225 --> 00:44:57,633
here, because they all have
advantages and disadvantages.

912
00:44:57,633 --> 00:44:58,800
But you're absolutely right.

913
00:44:58,800 --> 00:45:00,570
There are big differences.

914
00:45:00,570 --> 00:45:03,830
If, for example, there's
a time aspect to it,

915
00:45:03,830 --> 00:45:06,980
mechanically I can pull that
force off, and it goes away.

916
00:45:06,980 --> 00:45:09,420
There's a wave that goes
through the material.

917
00:45:09,420 --> 00:45:12,320
But it goes at sonic rates.

918
00:45:12,320 --> 00:45:16,400
The thermal could take a long
time to change anything there

919
00:45:16,400 --> 00:45:20,750
and certainly the chemical
depending on scale

920
00:45:20,750 --> 00:45:22,760
could be like that too.

921
00:45:22,760 --> 00:45:25,280
So it is important to know
what these different energy

922
00:45:25,280 --> 00:45:29,108
sources are, if only to say,
OK, these types of things

923
00:45:29,108 --> 00:45:30,650
are more important
when you're really

924
00:45:30,650 --> 00:45:32,942
faced with the decision of
what's the best I could ever

925
00:45:32,942 --> 00:45:34,370
expect this process to do.

926
00:45:34,370 --> 00:45:35,330
I've worked.

927
00:45:35,330 --> 00:45:36,200
I've done SBC.

928
00:45:36,200 --> 00:45:37,978
I've done process optimization.

929
00:45:37,978 --> 00:45:39,770
There's a fundamental
limitation because it

930
00:45:39,770 --> 00:45:41,540
uses mechanical energy.

931
00:45:41,540 --> 00:45:46,070
I'll never be able to do
the following or so on.

932
00:45:46,070 --> 00:45:48,740
So you have these types
of things interacting

933
00:45:48,740 --> 00:45:51,380
with how we apply them.

934
00:45:51,380 --> 00:45:53,697
And, of course,
you could say it's

935
00:45:53,697 --> 00:45:56,030
impossible to use all these
in all their different ways.

936
00:45:56,030 --> 00:45:57,710
But actually that's
not entirely true.

937
00:46:01,490 --> 00:46:04,510
So kind of said all that.

938
00:46:04,510 --> 00:46:05,690
So let's go on.

939
00:46:05,690 --> 00:46:09,920
Now, this eye
chart is an attempt

940
00:46:09,920 --> 00:46:12,020
to take this entire
taxonomy and then

941
00:46:12,020 --> 00:46:18,520
just populate it, this
chart, with some examples.

942
00:46:18,520 --> 00:46:21,340
And some of these
are no-brainers.

943
00:46:21,340 --> 00:46:23,890
And some of them could be
a little bit controversial.

944
00:46:23,890 --> 00:46:26,350
So what this says
is cross here, this

945
00:46:26,350 --> 00:46:29,720
is the removal mode
of transformation.

946
00:46:29,720 --> 00:46:32,500
And here is addition, and
here's formation, and here's

947
00:46:32,500 --> 00:46:33,850
deformation.

948
00:46:33,850 --> 00:46:36,340
And in each case
then, it's divided

949
00:46:36,340 --> 00:46:40,150
in half with serial and
parallel and then four different

950
00:46:40,150 --> 00:46:41,120
energy sources.

951
00:46:41,120 --> 00:46:43,480
So you look at each one
and say, OK, where where's

952
00:46:43,480 --> 00:46:45,700
my favorite process?

953
00:46:45,700 --> 00:46:48,360
So serial, removal.

954
00:46:48,360 --> 00:46:52,260
Mechanical, cutting, grinding,
broaching, polishing,

955
00:46:52,260 --> 00:46:54,370
water jet.

956
00:46:54,370 --> 00:46:55,570
Water jet is mechanical.

957
00:46:55,570 --> 00:46:57,490
It happens to be
fluid mechanical.

958
00:46:57,490 --> 00:46:58,810
But it's mechanical.

959
00:46:58,810 --> 00:47:02,620
Electrical, serial,
wire EDM, take

960
00:47:02,620 --> 00:47:04,280
a single skinny
little wire, drill

961
00:47:04,280 --> 00:47:06,760
a hole, something like that.

962
00:47:06,760 --> 00:47:08,320
Put a whole bunch
of them together.

963
00:47:08,320 --> 00:47:11,140
Do it all at once, say
with a formed electrode.

964
00:47:11,140 --> 00:47:15,130
Now, it's parallel EDM.

965
00:47:15,130 --> 00:47:19,510
Photolithography with
a wet etch if you

966
00:47:19,510 --> 00:47:23,510
want to think of it that way is
basically a parallel process.

967
00:47:23,510 --> 00:47:25,960
It's etching everywhere at once.

968
00:47:25,960 --> 00:47:28,210
But you just happen to put
a mask in a few places.

969
00:47:28,210 --> 00:47:29,410
That's your tool.

970
00:47:29,410 --> 00:47:31,465
So that it can't resist.

971
00:47:35,260 --> 00:47:37,930
I think Duane has already
talked about chemical mechanical

972
00:47:37,930 --> 00:47:41,530
polishing, which I'm told by the
experts in the field is really

973
00:47:41,530 --> 00:47:44,140
mechanical polishing.

974
00:47:44,140 --> 00:47:46,460
So if we take the
C off of there,

975
00:47:46,460 --> 00:47:50,950
then CMP is a mechanical
parallel process.

976
00:47:50,950 --> 00:47:52,682
If it's chemical
mechanical process,

977
00:47:52,682 --> 00:47:54,640
then I guess it has to
show up in both of them.

978
00:47:54,640 --> 00:47:55,150
Which is it?

979
00:47:55,150 --> 00:47:56,290
Is it both?

980
00:47:56,290 --> 00:47:58,884
AUDIENCE: The chemistry
softens the surface, and not

981
00:47:58,884 --> 00:48:01,344
the mechanical abrasion.

982
00:48:01,344 --> 00:48:02,393
So you have both.

983
00:48:02,393 --> 00:48:03,060
DAVID HARDT: OK.

984
00:48:05,730 --> 00:48:08,430
But the chemical by itself
would not remove any material.

985
00:48:08,430 --> 00:48:09,600
AUDIENCE: That's correct.

986
00:48:09,600 --> 00:48:13,350
DAVID HARDT: Chemically
assisted mechanical processing.

987
00:48:13,350 --> 00:48:15,690
AUDIENCE: Strangely enough,
the abrasion by itself

988
00:48:15,690 --> 00:48:17,730
would no remove any material.

989
00:48:17,730 --> 00:48:19,204
DAVID HARDT: Any at all?

990
00:48:19,204 --> 00:48:21,150
That's interesting.

991
00:48:21,150 --> 00:48:22,770
OK.

992
00:48:22,770 --> 00:48:25,020
Well, that's actually
an example here

993
00:48:25,020 --> 00:48:29,550
of where the chemical part is
actually affecting properties,

994
00:48:29,550 --> 00:48:31,330
not unusual.

995
00:48:31,330 --> 00:48:32,880
So this is still
true if I'm only

996
00:48:32,880 --> 00:48:40,752
talking about the geometry
change part of it.

997
00:48:40,752 --> 00:48:42,210
There's a bunch of
other ones here.

998
00:48:42,210 --> 00:48:45,630
One of the interesting things
is if you come over here

999
00:48:45,630 --> 00:48:51,300
to something like hot isostatic
pressing, a powder metallurgy

1000
00:48:51,300 --> 00:48:57,660
or powder ceramic process,
where you take uniform powders

1001
00:48:57,660 --> 00:48:59,640
and compress them in a mold.

1002
00:48:59,640 --> 00:49:01,500
So that's obviously
an addition process.

1003
00:49:01,500 --> 00:49:04,330
And then I sinter them and
then I do other stuff to it.

1004
00:49:04,330 --> 00:49:09,960
And I do it all at once
in a form tool, a can,

1005
00:49:09,960 --> 00:49:10,770
and I'm all set.

1006
00:49:13,540 --> 00:49:16,620
That's clearly a
parallel process.

1007
00:49:16,620 --> 00:49:23,760
And the result depends primarily
on the shape of the can.

1008
00:49:23,760 --> 00:49:28,860
Then Ely Sachs at MIT kind
of invented this process

1009
00:49:28,860 --> 00:49:30,720
called 3D printing.

1010
00:49:30,720 --> 00:49:33,870
And if you look at 3D printing,
it's not exactly this.

1011
00:49:33,870 --> 00:49:36,270
But it's essentially the
same as saying, OK, I'm

1012
00:49:36,270 --> 00:49:40,110
going to put down each
piece of that powder one

1013
00:49:40,110 --> 00:49:42,600
piece at a time.

1014
00:49:42,600 --> 00:49:46,170
He does it by joining the
powder one drop at a time.

1015
00:49:46,170 --> 00:49:47,153
He puts a binder on it.

1016
00:49:47,153 --> 00:49:48,570
Instead of binding
it all at once,

1017
00:49:48,570 --> 00:49:49,890
he puts a drop down at a time.

1018
00:49:49,890 --> 00:49:53,430
It's an ink jet type process.

1019
00:49:53,430 --> 00:49:55,200
Now, it becomes
a serial process.

1020
00:49:55,200 --> 00:49:59,355
And think about the difference
between these two processes.

1021
00:49:59,355 --> 00:50:01,200
If I've got this
big press that has

1022
00:50:01,200 --> 00:50:06,300
to push this powder into
a green compact, big piece

1023
00:50:06,300 --> 00:50:10,140
of equipment, going to
have an expensive tool,

1024
00:50:10,140 --> 00:50:12,750
whereas this 3D printing,
it's a desktop--

1025
00:50:12,750 --> 00:50:14,430
thing are desktop
versions of it--

1026
00:50:14,430 --> 00:50:18,180
desktop thing, all I have
to do is type in a CAD file.

1027
00:50:18,180 --> 00:50:20,430
It does a section file of it.

1028
00:50:20,430 --> 00:50:22,050
It creates this thing.

1029
00:50:22,050 --> 00:50:25,272
And I've got essentially
equivalent parts, not exactly

1030
00:50:25,272 --> 00:50:26,980
equivalent, essentially
equivalent parts.

1031
00:50:26,980 --> 00:50:32,230
So clearly this serial
process is much more flexible,

1032
00:50:32,230 --> 00:50:33,070
really great.

1033
00:50:33,070 --> 00:50:36,485
And I probably can
control the quality

1034
00:50:36,485 --> 00:50:38,110
better because of
it's not quite right,

1035
00:50:38,110 --> 00:50:40,085
I just change the
program a little bit.

1036
00:50:40,085 --> 00:50:42,460
If it was a little bit too
wide the last one I made,

1037
00:50:42,460 --> 00:50:44,312
I said, well, let's
reprogram the geometry

1038
00:50:44,312 --> 00:50:45,520
and bring it in a little bit.

1039
00:50:45,520 --> 00:50:46,680
And it just does it.

1040
00:50:46,680 --> 00:50:50,800
Whereas if I'm doing the
hot isostatic pressing,

1041
00:50:50,800 --> 00:50:54,310
I've got this big expensive
tool, and it's not quite right

1042
00:50:54,310 --> 00:50:58,330
and I can't heat it and cool
it like I did with the rolls

1043
00:50:58,330 --> 00:51:02,250
on the aluminum, I'm
kind of stuck with it.

1044
00:51:02,250 --> 00:51:06,900
So why would anybody do HIP,
when you've got 3D printing?

1045
00:51:06,900 --> 00:51:08,660
AUDIENCE: Rate and cost.

1046
00:51:08,660 --> 00:51:11,000
DAVID HARDT: Rate
and cost, absolutely.

1047
00:51:11,000 --> 00:51:15,290
You do the hot isostatic
pressing in minutes,

1048
00:51:15,290 --> 00:51:18,460
seconds, that sort of thing.

1049
00:51:18,460 --> 00:51:20,440
The 3D printing, the
fast ones, are going

1050
00:51:20,440 --> 00:51:23,590
to take you minutes to hours.

1051
00:51:23,590 --> 00:51:25,390
And it's volume dependent.

1052
00:51:25,390 --> 00:51:29,440
Whereas with the HIP,
it's much, much less so.

1053
00:51:29,440 --> 00:51:33,370
In general, why does anybody
do parallel processing?

1054
00:51:33,370 --> 00:51:35,230
Because it's really fast.

1055
00:51:35,230 --> 00:51:37,000
And the example I
always like to give

1056
00:51:37,000 --> 00:51:41,380
is imagine if someone took
a block of steel or better

1057
00:51:41,380 --> 00:51:44,170
yet aluminum and
said, OK, I'm going

1058
00:51:44,170 --> 00:51:46,990
to make all the body panels for
your car, the thin little body

1059
00:51:46,990 --> 00:51:52,240
panels, with my
machine tool over here.

1060
00:51:52,240 --> 00:51:56,110
Just imagine what it would
take to build that, as opposed

1061
00:51:56,110 --> 00:52:01,190
to going to a modern
high speed stamping shop.

1062
00:52:01,190 --> 00:52:03,800
Has anybody seen automobile
body stamping going on?

1063
00:52:03,800 --> 00:52:04,300
Yeah.

1064
00:52:04,300 --> 00:52:07,570
How long does it take to
make a side panel for a car

1065
00:52:07,570 --> 00:52:11,770
with like integral door frames
and all that other stuff?

1066
00:52:11,770 --> 00:52:14,990
Each given operation probably
takes about 2 seconds.

1067
00:52:14,990 --> 00:52:16,397
There's multiple stages.

1068
00:52:16,397 --> 00:52:18,730
So maybe we'll give it 10
seconds by the time it's done.

1069
00:52:18,730 --> 00:52:21,730
But blank metal in one end, and
these huge complex structures

1070
00:52:21,730 --> 00:52:24,670
coming out the other
end at incredible rates.

1071
00:52:24,670 --> 00:52:28,387
You're not going to do
that with a serial process.

1072
00:52:28,387 --> 00:52:30,220
Although I will say
they've done some things

1073
00:52:30,220 --> 00:52:32,678
with laser cutting and laser
welding where the thing really

1074
00:52:32,678 --> 00:52:33,910
whips along.

1075
00:52:33,910 --> 00:52:36,010
But it's still got a ways to go.

1076
00:52:36,010 --> 00:52:37,730
And it's much more costly.

1077
00:52:37,730 --> 00:52:40,510
So all these things do matter.

1078
00:52:40,510 --> 00:52:42,850
And they come in different ways.

1079
00:52:42,850 --> 00:52:48,258
Oh, just because I always like
to do this-- stereolithography,

1080
00:52:48,258 --> 00:52:49,050
how does that work?

1081
00:52:52,860 --> 00:52:54,240
It was the original--

1082
00:52:54,240 --> 00:52:56,800
I think-- the original
rapid prototyping process.

1083
00:52:56,800 --> 00:52:58,500
Anybody know what stereo--

1084
00:52:58,500 --> 00:53:00,250
what's the trade
name for that now?

1085
00:53:00,250 --> 00:53:01,980
That's the most
commercial of them.

1086
00:53:01,980 --> 00:53:03,873
There's a machine
right down the far end

1087
00:53:03,873 --> 00:53:05,790
of this hallway in the
architecture department

1088
00:53:05,790 --> 00:53:08,520
that's an STL machine.

1089
00:53:08,520 --> 00:53:09,900
Stereolithography?

1090
00:53:09,900 --> 00:53:11,590
I guess it's become passe now.

1091
00:53:11,590 --> 00:53:12,090
Yeah, Adam.

1092
00:53:12,090 --> 00:53:14,344
AUDIENCE: It's just-- I
don't know what liquid is,

1093
00:53:14,344 --> 00:53:17,620
but you select part of that
liquid material with the laser.

1094
00:53:17,620 --> 00:53:19,560
And then it runs that.

1095
00:53:19,560 --> 00:53:21,660
DAVID HARDT: Yeah, that's right.

1096
00:53:21,660 --> 00:53:24,450
There are these photo
curable polymers

1097
00:53:24,450 --> 00:53:28,230
that will be in a liquid
state at room temperature

1098
00:53:28,230 --> 00:53:30,310
and with just regular
light on them.

1099
00:53:30,310 --> 00:53:32,790
But if you hit them with
the right wavelength light,

1100
00:53:32,790 --> 00:53:34,740
they will polymerize.

1101
00:53:34,740 --> 00:53:37,560
They're UV curable
polymers that are

1102
00:53:37,560 --> 00:53:41,400
used for a lot of things,
like contact lenses and things

1103
00:53:41,400 --> 00:53:43,720
like that.

1104
00:53:43,720 --> 00:53:47,010
But this particular
case, what they said

1105
00:53:47,010 --> 00:53:49,710
is, well, instead of
putting it in a mold

1106
00:53:49,710 --> 00:53:52,020
and flashing it with
UV light everywhere,

1107
00:53:52,020 --> 00:53:54,960
what if we put a little
tiny spot of UV light on it?

1108
00:53:54,960 --> 00:53:58,080
Will it form a little
ball of polymer?

1109
00:53:58,080 --> 00:54:00,390
And the answer was sort of yeah.

1110
00:54:00,390 --> 00:54:03,030
So you have this bath.

1111
00:54:03,030 --> 00:54:04,950
I haven't walked by
there this month.

1112
00:54:04,950 --> 00:54:08,967
But there used to be one of
these glass walled classrooms

1113
00:54:08,967 --> 00:54:10,800
down here at the far
end of the fourth floor

1114
00:54:10,800 --> 00:54:13,740
in the architecture
department this white box

1115
00:54:13,740 --> 00:54:15,780
with a clear window in it.

1116
00:54:15,780 --> 00:54:17,050
And it's kind of lit up.

1117
00:54:17,050 --> 00:54:19,050
And there's usually
something going on in there.

1118
00:54:19,050 --> 00:54:21,870
And what you'll see is a bath
of nearly colorless liquid

1119
00:54:21,870 --> 00:54:23,575
with a platen on it.

1120
00:54:23,575 --> 00:54:25,950
And the platen starts at the
top with the very thin layer

1121
00:54:25,950 --> 00:54:28,620
of fluid on it.

1122
00:54:28,620 --> 00:54:30,810
And this laser,
usually not visible,

1123
00:54:30,810 --> 00:54:33,000
but this laser will be
dancing across the surface,

1124
00:54:33,000 --> 00:54:35,340
tracing an outline.

1125
00:54:35,340 --> 00:54:38,190
And that outline
will become solid.

1126
00:54:38,190 --> 00:54:41,820
And once it's polymerized, it'll
move it down and do it again.

1127
00:54:41,820 --> 00:54:46,290
So it's basically causing
a chemical reaction,

1128
00:54:46,290 --> 00:54:50,850
or in this case a polymerization
reaction, at a very small area

1129
00:54:50,850 --> 00:54:55,650
by hitting it with the right
amount of activation energy.

1130
00:54:55,650 --> 00:54:57,480
So that's stereolithography.

1131
00:54:57,480 --> 00:55:01,710
That would be a serial
chemical formation process.

1132
00:55:01,710 --> 00:55:03,210
You're going from
liquid to solid.

1133
00:55:06,480 --> 00:55:09,180
We also do-- in fact,
I was here last night

1134
00:55:09,180 --> 00:55:11,400
listening to a PhD
thesis from Singapore,

1135
00:55:11,400 --> 00:55:15,300
where what they did is they
took a mold, poured a UV curable

1136
00:55:15,300 --> 00:55:19,200
polymer on it, flashed
it with a UV lamp

1137
00:55:19,200 --> 00:55:23,460
over the whole thing for
about 30 seconds or something,

1138
00:55:23,460 --> 00:55:26,610
I think, and then
pulled it apart.

1139
00:55:26,610 --> 00:55:31,060
And it was all about the mold,
the mold quality, and filling

1140
00:55:31,060 --> 00:55:33,030
and that sort of thing.

1141
00:55:33,030 --> 00:55:38,580
And 90% of her thesis was
about-- well, not 90%--

1142
00:55:38,580 --> 00:55:42,270
a good percentage of her thesis
was about making the molds

1143
00:55:42,270 --> 00:55:44,520
and how well could I extract
this thing from the mold?

1144
00:55:44,520 --> 00:55:49,525
So physically, the same
material, the same process.

1145
00:55:49,525 --> 00:55:51,150
But in this case, a
really good example

1146
00:55:51,150 --> 00:55:52,950
of going from a
directed energy source

1147
00:55:52,950 --> 00:55:56,220
that was a point to a
directed energy source that

1148
00:55:56,220 --> 00:55:58,530
was really this entire surface.

1149
00:55:58,530 --> 00:56:00,480
So I guess my
point is, and now I

1150
00:56:00,480 --> 00:56:02,520
guess it's getting
a little bit dated,

1151
00:56:02,520 --> 00:56:07,920
but when these rapid prototyping
processes were all the rage,

1152
00:56:07,920 --> 00:56:12,180
it was interesting to notice
that on this taxonomy,

1153
00:56:12,180 --> 00:56:16,478
they simply, with the fact
that some people realized

1154
00:56:16,478 --> 00:56:18,520
and it's been done for a
lot of different things,

1155
00:56:18,520 --> 00:56:20,940
not just these, but
people realized that I

1156
00:56:20,940 --> 00:56:22,870
can take a parallel process.

1157
00:56:22,870 --> 00:56:27,030
And if I serialize
it, it all of a sudden

1158
00:56:27,030 --> 00:56:30,270
becomes a rapid
free form method.

1159
00:56:30,270 --> 00:56:32,430
It doesn't need any tooling.

1160
00:56:32,430 --> 00:56:33,810
And so you've got that example.

1161
00:56:33,810 --> 00:56:36,810
You've got what
turns out to be--

1162
00:56:36,810 --> 00:56:38,280
I guess I'd call it--

1163
00:56:38,280 --> 00:56:40,620
it's sort of like
a reaction molding

1164
00:56:40,620 --> 00:56:45,250
parallel reaction process to
a serial reaction process.

1165
00:56:45,250 --> 00:56:48,870
There's also with
powdered metals,

1166
00:56:48,870 --> 00:56:51,090
you can sinter them
thermally to get the shape.

1167
00:56:51,090 --> 00:56:54,420
And when people decided
they could sinter it locally

1168
00:56:54,420 --> 00:56:58,110
with a laser, you could
take a powder of metal

1169
00:56:58,110 --> 00:56:59,850
and zap it with a
laser and just get

1170
00:56:59,850 --> 00:57:03,390
things to sinter to
each other locally.

1171
00:57:03,390 --> 00:57:06,390
So they got they changed
the whole equation on how

1172
00:57:06,390 --> 00:57:08,910
the process is controlled,
which has effects

1173
00:57:08,910 --> 00:57:11,820
on all these different things.

1174
00:57:11,820 --> 00:57:14,310
Last thing, because
we're not going

1175
00:57:14,310 --> 00:57:16,470
to talk about it much
for the rest of the term,

1176
00:57:16,470 --> 00:57:20,010
but because it has been an
extremely important part

1177
00:57:20,010 --> 00:57:22,500
of manufacturing,
interestingly fading

1178
00:57:22,500 --> 00:57:24,570
in recent years for good
and sufficient reasons,

1179
00:57:24,570 --> 00:57:25,470
is flexibility.

1180
00:57:28,250 --> 00:57:31,850
What do you think
about if I were

1181
00:57:31,850 --> 00:57:33,950
to go to different
corners of this taxonomy

1182
00:57:33,950 --> 00:57:40,490
and say, all right, so let's put
a flexibility overlay on this?

1183
00:57:40,490 --> 00:57:44,660
And we'll talk about
flexibility here--

1184
00:57:44,660 --> 00:57:49,490
I guess, well, two common
ways of looking at flexibility

1185
00:57:49,490 --> 00:57:51,430
are sort of product flexibility.

1186
00:57:51,430 --> 00:57:54,150
So in our case, it's going to be
geometry flexibility, geometry

1187
00:57:54,150 --> 00:57:56,270
and material flexibility.

1188
00:57:56,270 --> 00:57:59,630
And the other would be
quantity flexibility,

1189
00:57:59,630 --> 00:58:05,240
ability to vary the capacity
or output of something

1190
00:58:05,240 --> 00:58:08,000
without having big
cost variances.

1191
00:58:08,000 --> 00:58:09,920
But let's do the first one.

1192
00:58:09,920 --> 00:58:12,200
We won't get into
that second one.

1193
00:58:12,200 --> 00:58:14,660
For flexibility of
this process to work

1194
00:58:14,660 --> 00:58:18,110
with different materials
in different shapes,

1195
00:58:18,110 --> 00:58:20,690
obviously, the extreme
example of flexibility

1196
00:58:20,690 --> 00:58:24,380
is every part's different.

1197
00:58:24,380 --> 00:58:28,800
Every part is different,
and the setup time is zero.

1198
00:58:28,800 --> 00:58:33,780
So mass production rates,
mass production cost savings,

1199
00:58:33,780 --> 00:58:41,650
but custom part capability.

1200
00:58:41,650 --> 00:58:43,400
These are lies somewhere
in between there.

1201
00:58:43,400 --> 00:58:46,940
But if I look at this
broadly, what do you think

1202
00:58:46,940 --> 00:58:49,420
is the most flexible?

1203
00:58:49,420 --> 00:58:52,240
Or most flexible
or more flexible?

1204
00:58:52,240 --> 00:58:55,000
If I look at the
taxonomy, what area

1205
00:58:55,000 --> 00:58:58,705
would you look at
for high flexibility?

1206
00:58:58,705 --> 00:59:00,420
AUDIENCE: Serial processes.

1207
00:59:00,420 --> 00:59:01,670
DAVID HARDT: Serial processes.

1208
00:59:01,670 --> 00:59:03,270
And why?

1209
00:59:03,270 --> 00:59:08,440
AUDIENCE: It's like if you're
working on a local [INAUDIBLE]

1210
00:59:08,440 --> 00:59:13,770
So I think it gives you more
flexibility [INAUDIBLE] I

1211
00:59:13,770 --> 00:59:17,640
guess feature by feature
and also part by part.

1212
00:59:17,640 --> 00:59:18,850
DAVID HARDT: Yeah, exactly.

1213
00:59:18,850 --> 00:59:23,886
I mean think of, again, the
ubiquitous example is a--

1214
00:59:23,886 --> 00:59:30,530
I'm trying to think of some
consumer-oriented parts

1215
00:59:30,530 --> 00:59:31,030
of this.

1216
00:59:31,030 --> 00:59:34,380
But I'm not coming up with them.

1217
00:59:34,380 --> 00:59:37,260
But, yeah, a machine tool.

1218
00:59:37,260 --> 00:59:38,760
Take a machine tool
with an end mill

1219
00:59:38,760 --> 00:59:40,802
and it can write your name
in a piece of plastic.

1220
00:59:43,950 --> 00:59:46,680
Once I programmed your name
in there and then your name

1221
00:59:46,680 --> 00:59:48,840
and then your name,
there's absolutely

1222
00:59:48,840 --> 00:59:52,530
no overhead to me switching,
because all I have to change

1223
00:59:52,530 --> 00:59:54,000
is the trajectory of the tool.

1224
00:59:54,000 --> 00:59:58,650
And nowadays with CNC control,
that's a zero cost changeover.

1225
00:59:58,650 --> 01:00:02,040
There's a minimal cost
in creating the programs

1226
01:00:02,040 --> 01:00:03,730
for simple things like that.

1227
01:00:03,730 --> 01:00:08,280
So, yeah, obviously, something
that is purely serial

1228
01:00:08,280 --> 01:00:09,420
makes a big difference.

1229
01:00:09,420 --> 01:00:12,360
And I'm going to add one other
thing, because if I hurry up

1230
01:00:12,360 --> 01:00:15,150
I'll get at least
to mention this.

1231
01:00:15,150 --> 01:00:23,190
I'll make the case that cutting
metal mechanically is maybe

1232
01:00:23,190 --> 01:00:27,060
the purest form of geometry
transformation, pure geometry

1233
01:00:27,060 --> 01:00:30,460
transformation with
no side effects.

1234
01:00:30,460 --> 01:00:34,750
So that also makes it very
flexible in that sense.

1235
01:00:34,750 --> 01:00:37,060
It's almost as if
all I have to do

1236
01:00:37,060 --> 01:00:40,060
is reprogram the trajectory
and nothing else changes

1237
01:00:40,060 --> 01:00:42,560
and everything's fine.

1238
01:00:42,560 --> 01:00:43,880
So we'll start from that.

1239
01:00:43,880 --> 01:00:49,450
And then we move to
other changes here.

1240
01:00:49,450 --> 01:00:54,280
Let's go to deformation,
serial defamation, bending.

1241
01:00:58,113 --> 01:00:59,946
I'm going to bend this,
three-point bending.

1242
01:01:02,980 --> 01:01:05,470
I'm calling it serial,
because most of the action

1243
01:01:05,470 --> 01:01:07,990
is happening right here.

1244
01:01:07,990 --> 01:01:10,210
And I'm not using form tools.

1245
01:01:10,210 --> 01:01:12,460
You can even think of this
as using knife-edge tools,

1246
01:01:12,460 --> 01:01:14,980
and I would get sort
of the same shape.

1247
01:01:14,980 --> 01:01:17,680
And the main thing
that determines

1248
01:01:17,680 --> 01:01:22,930
the shape, the main thing is how
far I push down in the middle.

1249
01:01:22,930 --> 01:01:25,540
So that's pretty flexible.

1250
01:01:25,540 --> 01:01:29,320
I mean if I want 45 degrees,
I just take it down less.

1251
01:01:29,320 --> 01:01:33,200
If I go down farther,
I take it down more.

1252
01:01:33,200 --> 01:01:36,580
But as can be shown--

1253
01:01:36,580 --> 01:01:38,890
and it is in the notes, but
we probably won't have time

1254
01:01:38,890 --> 01:01:39,640
to go through it--

1255
01:01:39,640 --> 01:01:43,140
as can be shown, it
makes a huge difference

1256
01:01:43,140 --> 01:01:47,100
what this material is and
what the underlying machine

1257
01:01:47,100 --> 01:01:48,990
structure looks like.

1258
01:01:48,990 --> 01:01:52,050
And it also-- and
this really kind of

1259
01:01:52,050 --> 01:01:54,870
gets us to the next
theme here-- it also

1260
01:01:54,870 --> 01:01:59,370
depends very strongly on the
uniformity of this material.

1261
01:01:59,370 --> 01:02:02,640
So I'll make the statement
that the natural variations out

1262
01:02:02,640 --> 01:02:06,900
of an aluminum mill, maybe not
the Alcoa, Tennessee, mill,

1263
01:02:06,900 --> 01:02:10,290
but the other ones,
of aluminum is enough

1264
01:02:10,290 --> 01:02:13,830
that it can completely
confound precise control

1265
01:02:13,830 --> 01:02:15,570
of a process like this.

1266
01:02:15,570 --> 01:02:17,820
The natural variation
of a piece of aluminum

1267
01:02:17,820 --> 01:02:20,250
like this that I'm
going to turn just

1268
01:02:20,250 --> 01:02:21,720
doesn't make any difference.

1269
01:02:21,720 --> 01:02:23,310
Sure, if I put a
different alloy in,

1270
01:02:23,310 --> 01:02:26,820
or I sneak in steel or
titanium instead of aluminum,

1271
01:02:26,820 --> 01:02:28,770
that's a big mess up.

1272
01:02:28,770 --> 01:02:33,360
But if I just say,
well, you know, here's

1273
01:02:33,360 --> 01:02:34,200
a piece of aluminum.

1274
01:02:34,200 --> 01:02:35,790
We did it in this
mill over here,

1275
01:02:35,790 --> 01:02:39,630
and it came out with the
following properties.

1276
01:02:39,630 --> 01:02:41,100
It's elasticity.

1277
01:02:41,100 --> 01:02:43,050
It's yield strength.

1278
01:02:43,050 --> 01:02:45,390
It's strain hardening
characteristics.

1279
01:02:45,390 --> 01:02:47,893
And then I get supposedly
the same material

1280
01:02:47,893 --> 01:02:48,810
from a different mill.

1281
01:02:48,810 --> 01:02:50,970
And they're 10% different.

1282
01:02:50,970 --> 01:02:54,390
Not the elasticity, by the
way, but all the others.

1283
01:02:54,390 --> 01:02:56,670
10% different.

1284
01:02:56,670 --> 01:03:00,210
Huge difference here,
virtually no difference

1285
01:03:00,210 --> 01:03:01,360
for the machining.

1286
01:03:01,360 --> 01:03:03,060
So there's an
inherent sensitivity

1287
01:03:03,060 --> 01:03:05,050
of the processes to that.

1288
01:03:05,050 --> 01:03:09,240
So if I look just at this
purely serial parallel thing,

1289
01:03:09,240 --> 01:03:11,910
yeah, serial is
better than parallel.

1290
01:03:11,910 --> 01:03:14,310
I think we can show in
general that removal

1291
01:03:14,310 --> 01:03:17,358
tends to be the least sensitive
to material properties.

1292
01:03:17,358 --> 01:03:19,650
It tends to be the least
sensitive of all these things.

1293
01:03:19,650 --> 01:03:23,040
So serial removal kind
of wins in most cases

1294
01:03:23,040 --> 01:03:24,210
in terms of flexibility.

1295
01:03:26,760 --> 01:03:29,280
Deformation is
generally a killer

1296
01:03:29,280 --> 01:03:31,050
in terms of flexibility
for these reasons

1297
01:03:31,050 --> 01:03:32,320
that we've talked about.

1298
01:03:32,320 --> 01:03:35,370
And in many cases--

1299
01:03:35,370 --> 01:03:40,500
well, certainly anything that
involves a parallel energy

1300
01:03:40,500 --> 01:03:44,310
exchange sort of starts
off behind the eight ball

1301
01:03:44,310 --> 01:03:45,580
with respect to flexibility.

1302
01:03:45,580 --> 01:03:46,110
Simon.

1303
01:03:46,110 --> 01:03:48,610
AUDIENCE: What about the
chemical [INAUDIBLE]??

1304
01:03:48,610 --> 01:03:51,360
I mean, they throw in
all sorts of parts.

1305
01:03:51,360 --> 01:03:56,070
And they come out
with the coating.

1306
01:03:56,070 --> 01:03:58,470
And I mean there
is no dependency--

1307
01:03:58,470 --> 01:04:00,370
DAVID HARDT: That's
a very good point.

1308
01:04:00,370 --> 01:04:02,040
That's a really good point.

1309
01:04:02,040 --> 01:04:03,243
I'm glad you raised that.

1310
01:04:03,243 --> 01:04:04,410
I hadn't thought about that.

1311
01:04:04,410 --> 01:04:08,730
But a process like this, some
of these addition processes,

1312
01:04:08,730 --> 01:04:11,910
any sort of a plating
or coating process

1313
01:04:11,910 --> 01:04:20,010
where you put stuff into
a liquid or vapor bath,

1314
01:04:20,010 --> 01:04:22,080
it doesn't care about
the shape, does it?

1315
01:04:22,080 --> 01:04:24,053
I mean at a microscopic
level it might.

1316
01:04:24,053 --> 01:04:24,970
But, yeah, it doesn't.

1317
01:04:24,970 --> 01:04:25,960
That's a good point.

1318
01:04:25,960 --> 01:04:29,815
So in terms of
geometry, which there's

1319
01:04:29,815 --> 01:04:31,440
the underlying
geometry, the substrate,

1320
01:04:31,440 --> 01:04:35,280
plus whatever thickness
you add, to my knowledge,

1321
01:04:35,280 --> 01:04:38,280
if I have a big piece over
here and right next to it

1322
01:04:38,280 --> 01:04:40,693
a little piece over here,
another one over here,

1323
01:04:40,693 --> 01:04:42,110
they're independent
of each other.

1324
01:04:42,110 --> 01:04:43,990
So they all deposit
at the same rate,

1325
01:04:43,990 --> 01:04:45,490
unless you do
something really dumb.

1326
01:04:45,490 --> 01:04:46,800
It's a good point.

1327
01:04:46,800 --> 01:04:47,340
Good point.

1328
01:04:47,340 --> 01:04:50,720
I don't know how
to pull that out.

1329
01:04:50,720 --> 01:04:54,580
But in that sense--

1330
01:04:54,580 --> 01:04:56,330
well, to relate it to
what we said before,

1331
01:04:56,330 --> 01:05:00,880
the energy exchange
area is determined

1332
01:05:00,880 --> 01:05:04,980
by the shape of the substrate,
not the shape of the tool.

1333
01:05:04,980 --> 01:05:07,820
And so in a situation like that,
the shape of the substrate,

1334
01:05:07,820 --> 01:05:12,080
if it's right and I can change
it each time I put it in,

1335
01:05:12,080 --> 01:05:14,060
I get high
flexibility with that.

1336
01:05:14,060 --> 01:05:14,980
Yeah, good point.

1337
01:05:17,800 --> 01:05:20,450
I have to remember that.

1338
01:05:20,450 --> 01:05:23,060
OK, enough on the taxonomy.

1339
01:05:29,310 --> 01:05:35,030
Now, the last thing I want to
talk about is what goes wrong.

1340
01:05:35,030 --> 01:05:36,885
What we've been
talking about so far--

1341
01:05:36,885 --> 01:05:38,260
we've made some
reference to it--

1342
01:05:38,260 --> 01:05:39,980
what we've been
talking about so far

1343
01:05:39,980 --> 01:05:42,500
is how to make major changes.

1344
01:05:42,500 --> 01:05:47,742
I want to go from this diameter
down to half that diameter.

1345
01:05:47,742 --> 01:05:48,950
Well, I have to push this in.

1346
01:05:48,950 --> 01:05:50,330
I have to make chips.

1347
01:05:50,330 --> 01:05:52,520
And I have to push
this down so far.

1348
01:05:52,520 --> 01:05:54,920
But what I want to talk
about is, why doesn't this

1349
01:05:54,920 --> 01:05:58,340
always come out to the
same angle every time?

1350
01:05:58,340 --> 01:06:01,640
Why is the third part
out of the run of 50

1351
01:06:01,640 --> 01:06:05,300
different from the 24th
part and that sort of thing?

1352
01:06:05,300 --> 01:06:11,060
And why, when I machine this,
is it not the same diameter

1353
01:06:11,060 --> 01:06:13,740
everywhere?

1354
01:06:13,740 --> 01:06:19,280
And so it gets into looking
at the sources of variation.

1355
01:06:19,280 --> 01:06:23,840
And by our definition
of a process parameter,

1356
01:06:23,840 --> 01:06:26,140
we're going to say,
well, it-- oops.

1357
01:06:26,140 --> 01:06:29,040
Don't do that.

1358
01:06:29,040 --> 01:06:30,980
I'll say yes, but what did I do?

1359
01:06:38,498 --> 01:06:49,410
By our definition of this,
it's all wrapped up somehow--

1360
01:06:49,410 --> 01:06:51,840
well, in the end,
it's all wrapped up

1361
01:06:51,840 --> 01:06:54,060
in this functional
relationship, but primarily

1362
01:06:54,060 --> 01:06:57,180
through these
process parameters.

1363
01:06:57,180 --> 01:06:59,910
So we're going to use those
to try and understand it.

1364
01:06:59,910 --> 01:07:02,400
So let's break down
these process parameters

1365
01:07:02,400 --> 01:07:10,058
in a little bit more
of a logical fashion.

1366
01:07:10,058 --> 01:07:11,850
And I'm going to do it
in the following way

1367
01:07:11,850 --> 01:07:13,933
with the following definitions.

1368
01:07:13,933 --> 01:07:15,600
First of all, we're
going to have alphas

1369
01:07:15,600 --> 01:07:17,230
associated with the equipment.

1370
01:07:17,230 --> 01:07:19,230
And then we're going to
have alphas associated--

1371
01:07:19,230 --> 01:07:20,438
let me go back here actually.

1372
01:07:20,438 --> 01:07:21,970
I need my picture.

1373
01:07:21,970 --> 01:07:24,930
So we're going to have these
parameters associated just

1374
01:07:24,930 --> 01:07:26,673
with the equipment.

1375
01:07:26,673 --> 01:07:28,590
And I think I've already
explained why we want

1376
01:07:28,590 --> 01:07:30,460
to distinguish between the two.

1377
01:07:30,460 --> 01:07:33,780
So now, we're talking about
properties, variables,

1378
01:07:33,780 --> 01:07:36,330
things I can adjust,
things that happen

1379
01:07:36,330 --> 01:07:38,820
that are staying with that
piece of iron that's bolted down

1380
01:07:38,820 --> 01:07:39,880
to the factory floor.

1381
01:07:39,880 --> 01:07:44,232
And then a similar
set, but for the stuff

1382
01:07:44,232 --> 01:07:45,690
that goes in and
out of the machine

1383
01:07:45,690 --> 01:07:47,107
or that flows
through the machine.

1384
01:07:47,107 --> 01:07:48,160
It doesn't go in and out.

1385
01:07:48,160 --> 01:07:50,740
So that's why we
distinguish between them.

1386
01:07:50,740 --> 01:07:52,890
So let's just focus--

1387
01:07:52,890 --> 01:07:56,520
I don't know, let's focus on
the machine, on the equipment.

1388
01:07:56,520 --> 01:08:00,180
If I think of two broad
classifications of a machine--

1389
01:08:00,180 --> 01:08:03,060
well, let's see,
try this exercise.

1390
01:08:03,060 --> 01:08:06,000
I think everybody's familiar
with a machine tool.

1391
01:08:06,000 --> 01:08:10,190
Simple lathe, it's sitting
here in front of us.

1392
01:08:10,190 --> 01:08:12,090
And it's not doing a thing.

1393
01:08:12,090 --> 01:08:12,930
It's not moving.

1394
01:08:12,930 --> 01:08:15,780
It's not even plugged in.

1395
01:08:15,780 --> 01:08:18,330
What alphas, what
characteristics

1396
01:08:18,330 --> 01:08:20,939
can you tell me about it
just by looking at it?

1397
01:08:20,939 --> 01:08:21,779
It's not moving.

1398
01:08:24,487 --> 01:08:27,029
If you were to describe it from
an engineering point of view,

1399
01:08:27,029 --> 01:08:29,237
what are the kinds of things
you'd worry about on it?

1400
01:08:29,237 --> 01:08:30,100
AUDIENCE: Stiffness.

1401
01:08:30,100 --> 01:08:31,710
DAVID HARDT: Stiffness.

1402
01:08:31,710 --> 01:08:32,460
How stiff is it?

1403
01:08:32,460 --> 01:08:33,235
Does it deform?

1404
01:08:33,235 --> 01:08:33,735
Yeah.

1405
01:08:36,710 --> 01:08:37,979
That's almost it.

1406
01:08:37,979 --> 01:08:39,229
That's a good one right there.

1407
01:08:39,229 --> 01:08:45,560
Stiffness, straightness,
some details

1408
01:08:45,560 --> 01:08:47,973
of mechanical
characteristics of it.

1409
01:08:47,973 --> 01:08:49,640
AUDIENCE: Thermal
expansion coefficient.

1410
01:08:49,640 --> 01:08:51,682
DAVID HARDT: Yeah, thermal
expansion coefficient,

1411
01:08:51,682 --> 01:08:52,609
very important stuff.

1412
01:08:52,609 --> 01:08:55,010
All those things that
basically go into

1413
01:08:55,010 --> 01:08:56,990
is the structure
and where I'm going

1414
01:08:56,990 --> 01:08:59,600
to direct that energy source
where I think it's going to be?

1415
01:09:02,390 --> 01:09:04,340
Now, I turn it on.

1416
01:09:04,340 --> 01:09:05,779
It starts moving.

1417
01:09:05,779 --> 01:09:08,140
And I start machining.

1418
01:09:08,140 --> 01:09:10,140
Forget about the chips
and all that other stuff,

1419
01:09:10,140 --> 01:09:11,550
but just the machine itself.

1420
01:09:11,550 --> 01:09:15,064
What other characteristics
of the machine

1421
01:09:15,064 --> 01:09:16,439
are you now going
to worry about?

1422
01:09:19,229 --> 01:09:20,550
AUDIENCE: The turning speed.

1423
01:09:20,550 --> 01:09:23,670
DAVID HARDT: Yeah, the
turning speed, exactly.

1424
01:09:23,670 --> 01:09:24,600
The speed.

1425
01:09:24,600 --> 01:09:25,109
What else?

1426
01:09:29,640 --> 01:09:31,290
AUDIENCE: Accuracy
of the rotation.

1427
01:09:31,290 --> 01:09:35,430
DAVID HARDT: The accuracy of
the rotation, yeah, OK, yeah.

1428
01:09:35,430 --> 01:09:38,580
But now we've got the
turning speed, now

1429
01:09:38,580 --> 01:09:41,609
what's the difference from
the machine's point of view

1430
01:09:41,609 --> 01:09:45,189
if I've got the tool
and I'm coming along--

1431
01:09:45,189 --> 01:09:47,910
I think you guys can see this--
if I'm coming along like this?

1432
01:09:47,910 --> 01:09:50,550
Right now I'm
characterizing the machine.

1433
01:09:50,550 --> 01:09:52,200
And now I'm characterizing
the machine.

1434
01:09:52,200 --> 01:09:55,140
I've hit the material, and
I'm starting the machine.

1435
01:09:55,140 --> 01:09:59,240
What's the difference
between when I'm here

1436
01:09:59,240 --> 01:10:01,562
and when I'm here?

1437
01:10:01,562 --> 01:10:03,354
AUDIENCE: Negative vibrations.

1438
01:10:03,354 --> 01:10:05,310
DAVID HARDT: Yeah,
you've skipped something.

1439
01:10:05,310 --> 01:10:06,150
Go ahead, I think--

1440
01:10:06,150 --> 01:10:07,863
AUDIENCE: [INAUDIBLE]

1441
01:10:07,863 --> 01:10:09,780
DAVID HARDT: Yeah, you
talked about the speed.

1442
01:10:09,780 --> 01:10:13,860
So I have a speed here, and
I have a rotation speed.

1443
01:10:13,860 --> 01:10:17,178
But if there's no force,
like there's no power,

1444
01:10:17,178 --> 01:10:17,970
there's no nothing.

1445
01:10:17,970 --> 01:10:19,980
No nothing much happening.

1446
01:10:19,980 --> 01:10:21,510
That's good grammar.

1447
01:10:21,510 --> 01:10:26,050
But if I come along here, all
of a sudden the force changes.

1448
01:10:26,050 --> 01:10:29,820
So as a minimum, you've got
these two sets of variables.

1449
01:10:29,820 --> 01:10:32,320
You've got how stiff
is the machine?

1450
01:10:32,320 --> 01:10:35,160
How does it react to
things like forces?

1451
01:10:35,160 --> 01:10:38,220
How straight is the machine
if I move this way relative

1452
01:10:38,220 --> 01:10:41,160
to the axis of rotation--
that's your accuracy thing--

1453
01:10:41,160 --> 01:10:41,850
is it that way?

1454
01:10:41,850 --> 01:10:43,590
And those are properties
that they're not

1455
01:10:43,590 --> 01:10:45,473
independent of whether
it's moving or not.

1456
01:10:45,473 --> 01:10:46,890
But you kind of
look at it and you

1457
01:10:46,890 --> 01:10:49,320
say it's the basic
characteristic of the machine.

1458
01:10:49,320 --> 01:10:51,780
And then you've got these
transient ones that are only

1459
01:10:51,780 --> 01:10:54,180
related to the energy exchange.

1460
01:10:54,180 --> 01:10:55,860
So you'd agree that
if there's no force,

1461
01:10:55,860 --> 01:10:57,240
there's no energy exchange.

1462
01:10:57,240 --> 01:10:59,880
But as soon as I have
a force and a velocity,

1463
01:10:59,880 --> 01:11:02,940
I'm putting mechanical
power into that thing.

1464
01:11:02,940 --> 01:11:05,340
And something's going to happen.

1465
01:11:05,340 --> 01:11:07,260
So from that we can
actually say, OK, there

1466
01:11:07,260 --> 01:11:08,648
are two types of variables.

1467
01:11:08,648 --> 01:11:11,190
Think of these sort of ones that
are intrinsic variables that

1468
01:11:11,190 --> 01:11:16,198
characterize the basic
properties of the machine.

1469
01:11:16,198 --> 01:11:18,240
And if we were doing
applied mechanics, we'd say,

1470
01:11:18,240 --> 01:11:21,780
those are the constitutive
properties of the material,

1471
01:11:21,780 --> 01:11:24,900
or they're constitutive
properties of our machine.

1472
01:11:24,900 --> 01:11:28,020
And then there are
the energy states,

1473
01:11:28,020 --> 01:11:32,550
how things change over time
as the energy waxes and wanes

1474
01:11:32,550 --> 01:11:34,990
and interchanges and
things like that.

1475
01:11:34,990 --> 01:11:38,790
And those are useful divisions,
because, for example, how

1476
01:11:38,790 --> 01:11:40,860
easily can I change the
stiffness of a machine?

1477
01:11:43,860 --> 01:11:44,890
It can be done.

1478
01:11:44,890 --> 01:11:46,450
I could buy a new one.

1479
01:11:46,450 --> 01:11:49,490
I could go in and put
in some more supports

1480
01:11:49,490 --> 01:11:50,920
and that kind of stuff.

1481
01:11:50,920 --> 01:11:54,990
Or I can take some away
and make it less stiff.

1482
01:11:54,990 --> 01:11:56,160
Kind of hard.

1483
01:11:56,160 --> 01:11:56,810
Yeah.

1484
01:11:56,810 --> 01:11:59,570
AUDIENCE: It depends
a lot on where

1485
01:11:59,570 --> 01:12:02,640
I have my [INAUDIBLE]
if I have a mill,

1486
01:12:02,640 --> 01:12:06,990
I can take the table out very
far and use it [INAUDIBLE]

1487
01:12:06,990 --> 01:12:09,758
DAVID HARDT: Oh,
yeah, yeah, stiffness

1488
01:12:09,758 --> 01:12:10,800
is not a single quantity.

1489
01:12:10,800 --> 01:12:11,100
You're right.

1490
01:12:11,100 --> 01:12:13,290
I can find stiffer regions
and less stiff regions.

1491
01:12:13,290 --> 01:12:15,000
But I guess what
I'm saying is if you

1492
01:12:15,000 --> 01:12:18,810
need to elevate the stiffness
of-- there's no acceptable spot

1493
01:12:18,810 --> 01:12:20,610
in it, what do you do?

1494
01:12:20,610 --> 01:12:22,380
You have to change the iron.

1495
01:12:22,380 --> 01:12:23,910
You have to go in
and make a change.

1496
01:12:23,910 --> 01:12:26,130
It's not something that
we would call really,

1497
01:12:26,130 --> 01:12:29,400
at this case, a
control variable.

1498
01:12:29,400 --> 01:12:34,170
On the other hand, if I need to
change the speed at which I'm

1499
01:12:34,170 --> 01:12:37,250
cutting, change the speed
at which I'm cutting

1500
01:12:37,250 --> 01:12:39,140
and it changes.

1501
01:12:39,140 --> 01:12:44,510
So again, there's an important
distinction between those two.

1502
01:12:44,510 --> 01:12:47,810
And our ability to know them
as well as to control them

1503
01:12:47,810 --> 01:12:49,460
is vastly different.

1504
01:12:49,460 --> 01:12:54,680
Now, the same thing holds true
for this, this piece of sheet

1505
01:12:54,680 --> 01:12:56,920
metal in its undeformed state.

1506
01:12:56,920 --> 01:12:59,570
This is really hard stuff.

1507
01:12:59,570 --> 01:13:00,320
It's like butter.

1508
01:13:04,400 --> 01:13:07,650
If I just put this piece
of sheet metal down here,

1509
01:13:07,650 --> 01:13:08,900
how would you characterize it?

1510
01:13:14,220 --> 01:13:14,880
Yeah, please.

1511
01:13:14,880 --> 01:13:15,990
AUDIENCE: Yield strength.

1512
01:13:15,990 --> 01:13:19,220
DAVID HARDT: Yield strength,
extremely important.

1513
01:13:19,220 --> 01:13:21,293
Anything else?

1514
01:13:21,293 --> 01:13:24,180
AUDIENCE: Elastic.

1515
01:13:24,180 --> 01:13:25,356
DAVID HARDT: Go ahead, Adam.

1516
01:13:25,356 --> 01:13:26,580
AUDIENCE: Elasticity.

1517
01:13:26,580 --> 01:13:27,907
DAVID HARDT: Yeah, elasticity.

1518
01:13:27,907 --> 01:13:28,740
AUDIENCE: Thickness.

1519
01:13:28,740 --> 01:13:31,001
DAVID HARDT: Thickness.

1520
01:13:31,001 --> 01:13:32,170
AUDIENCE: Temperature.

1521
01:13:32,170 --> 01:13:34,750
DAVID HARDT: Temperature.

1522
01:13:34,750 --> 01:13:37,420
Actually, I'm going to
disagree with you on that.

1523
01:13:37,420 --> 01:13:39,520
No.

1524
01:13:39,520 --> 01:13:41,530
Why does temperature matter?

1525
01:13:41,530 --> 01:13:44,086
AUDIENCE: Because it
changes the dimension.

1526
01:13:44,086 --> 01:13:45,490
DAVID HARDT: OK.

1527
01:13:45,490 --> 01:13:48,880
So there's a thermal expansion
characteristic on this.

1528
01:13:48,880 --> 01:13:52,930
That's very important point.

1529
01:13:52,930 --> 01:13:55,540
When I say characterizing
this, you don't characterize it

1530
01:13:55,540 --> 01:13:56,800
by its temperature.

1531
01:13:56,800 --> 01:14:00,160
You characterize it by its
reaction to temperature.

1532
01:14:00,160 --> 01:14:02,770
I don't characterize it
by its stress or strain.

1533
01:14:02,770 --> 01:14:05,710
I characterize it by its
reaction to stress or strain.

1534
01:14:05,710 --> 01:14:06,460
So those are all--

1535
01:14:06,460 --> 01:14:08,710
again, very clearly
for piece of metal,

1536
01:14:08,710 --> 01:14:10,638
it is constitutive properties.

1537
01:14:10,638 --> 01:14:13,180
And we could also worry about
its chemical reactivity and all

1538
01:14:13,180 --> 01:14:13,888
this other stuff.

1539
01:14:13,888 --> 01:14:16,600
But its inherent
characteristic of it,

1540
01:14:16,600 --> 01:14:23,050
which describes how it
reacts to impinging energy.

1541
01:14:23,050 --> 01:14:26,950
So the mechanical
energy I put in here

1542
01:14:26,950 --> 01:14:29,860
combined with its
elasticity, its yield stress,

1543
01:14:29,860 --> 01:14:35,170
and other things, determines how
far it bends and how it bends.

1544
01:14:35,170 --> 01:14:36,680
So we distinguish
between the two.

1545
01:14:36,680 --> 01:14:40,000
Again, so when this
baby is sitting here

1546
01:14:40,000 --> 01:14:43,750
waiting to be bent, it's got
its constitutive properties.

1547
01:14:43,750 --> 01:14:49,750
As it's being bent, it's
now bearing external loads

1548
01:14:49,750 --> 01:14:51,130
and displacements.

1549
01:14:51,130 --> 01:14:54,970
It's stressing and straining.

1550
01:14:54,970 --> 01:14:58,730
And that's a transient state.

1551
01:14:58,730 --> 01:15:00,130
It's an energy transfer.

1552
01:15:00,130 --> 01:15:02,330
And those are two
different things.

1553
01:15:02,330 --> 01:15:04,840
They're both important to
determining what comes out

1554
01:15:04,840 --> 01:15:07,660
here, because if I
said, OK, go back

1555
01:15:07,660 --> 01:15:09,940
to your computers
or your textbooks

1556
01:15:09,940 --> 01:15:14,410
and give me an analysis of what
it takes to get this shape,

1557
01:15:14,410 --> 01:15:16,750
you're going to need to
know the characteristics

1558
01:15:16,750 --> 01:15:18,685
of the material,
stiffness, yield

1559
01:15:18,685 --> 01:15:19,810
stress, that sort of thing.

1560
01:15:19,810 --> 01:15:21,430
You're also going
to need to know

1561
01:15:21,430 --> 01:15:23,110
what forces and
displacements I put

1562
01:15:23,110 --> 01:15:26,217
into it, which will tell
you what happened internally

1563
01:15:26,217 --> 01:15:26,800
to this thing.

1564
01:15:26,800 --> 01:15:30,380
What stresses and
strains did it have?

1565
01:15:30,380 --> 01:15:34,120
Same thing with this,
I needed to know

1566
01:15:34,120 --> 01:15:37,480
what the characteristic
of the polymer was.

1567
01:15:37,480 --> 01:15:38,860
How did it react to temperature?

1568
01:15:38,860 --> 01:15:40,810
What was its viscosity
with temperature?

1569
01:15:40,810 --> 01:15:42,820
What's its heat transfer
characteristics?

1570
01:15:42,820 --> 01:15:45,230
And then I needed to know
what temperature it was,

1571
01:15:45,230 --> 01:15:47,230
what pressure it saw, and
what the heat transfer

1572
01:15:47,230 --> 01:15:50,500
characteristics
of the mold were.

1573
01:15:50,500 --> 01:15:53,200
So what does this all lead to?

1574
01:15:53,200 --> 01:15:58,880
These four babies-- to two major
things, states and properties--

1575
01:15:58,880 --> 01:16:00,650
states and properties.

1576
01:16:00,650 --> 01:16:03,820
Energy states,
transient things, things

1577
01:16:03,820 --> 01:16:06,055
that don't hang
around, things that

1578
01:16:06,055 --> 01:16:08,430
are just there to accomplish
what we wanted to accomplish

1579
01:16:08,430 --> 01:16:09,600
and then they go away.

1580
01:16:09,600 --> 01:16:13,232
And properties, which, if
you will, we can change them.

1581
01:16:13,232 --> 01:16:14,940
But they kind of are
there when we begin,

1582
01:16:14,940 --> 01:16:16,357
and they're still
there when we're

1583
01:16:16,357 --> 01:16:24,570
done, and are more inherent to
either the equipment itself,

1584
01:16:24,570 --> 01:16:26,910
essentially the material
or the equipment

1585
01:16:26,910 --> 01:16:31,450
or inherent to the
material itself.

1586
01:16:31,450 --> 01:16:33,090
So when we talk
about energy states,

1587
01:16:33,090 --> 01:16:35,610
this one can be made
much more precise

1588
01:16:35,610 --> 01:16:37,650
than we have time to do here.

1589
01:16:37,650 --> 01:16:42,540
And those of us who are
students of system dynamics,

1590
01:16:42,540 --> 01:16:47,100
in the mechanical, not
in the Sturman sense,

1591
01:16:47,100 --> 01:16:50,730
but in the Painter
and Richardson sense

1592
01:16:50,730 --> 01:16:54,360
of system dynamics,
understand that you can really

1593
01:16:54,360 --> 01:16:56,400
do a good job of describing
the world by simply

1594
01:16:56,400 --> 01:17:01,830
talking about energy or power
and constitutive relationships.

1595
01:17:01,830 --> 01:17:07,117
And you can model anything as
how it reacts to these things.

1596
01:17:07,117 --> 01:17:08,700
So that's really
what we've done here.

1597
01:17:08,700 --> 01:17:13,320
We said the equipment
either provides or absorbs

1598
01:17:13,320 --> 01:17:15,060
some form of energy--

1599
01:17:15,060 --> 01:17:18,990
force, velocity, pressure,
flow, force displacement,

1600
01:17:18,990 --> 01:17:23,760
that sort of thing, voltage
current, heat transfer,

1601
01:17:23,760 --> 01:17:25,770
heat flow.

1602
01:17:25,770 --> 01:17:30,800
And those are the things
that determine specifically

1603
01:17:30,800 --> 01:17:35,180
what happens in the
interaction between these two.

1604
01:17:35,180 --> 01:17:36,590
And then the
properties, which is

1605
01:17:36,590 --> 01:17:38,780
sort of what's going to
happen when that energy is

1606
01:17:38,780 --> 01:17:40,880
transferred, are
all these things

1607
01:17:40,880 --> 01:17:43,490
we've talked about-- margins
of elasticity, plastic flow

1608
01:17:43,490 --> 01:17:45,980
properties, viscosity, sort
of almost the same thing,

1609
01:17:45,980 --> 01:17:47,870
resistance, inductance,
capacitance,

1610
01:17:47,870 --> 01:17:49,490
chemical reactivity,
heat transfer

1611
01:17:49,490 --> 01:17:53,690
coefficient, thermal
diffusivities,

1612
01:17:53,690 --> 01:17:55,490
intensive constituent
properties.

1613
01:17:55,490 --> 01:17:58,190
Plus, because someone
mentioned this before,

1614
01:17:58,190 --> 01:18:00,690
someone mentioned thickness,
so this is extremely important.

1615
01:18:00,690 --> 01:18:02,750
So are the other two dimensions.

1616
01:18:02,750 --> 01:18:04,550
These dimensions are important.

1617
01:18:04,550 --> 01:18:06,590
And these dimensions
are important.

1618
01:18:06,590 --> 01:18:09,710
And so it turns out the
object of all our affection

1619
01:18:09,710 --> 01:18:15,620
is actually the
geometry in the end.

1620
01:18:15,620 --> 01:18:19,380
So it's sort of an extensive
property of the material.

1621
01:18:19,380 --> 01:18:22,140
But we also have to worry about
the geometry before and after.

1622
01:18:22,140 --> 01:18:24,560
And we worry about
the geometry of--

1623
01:18:24,560 --> 01:18:26,930
obviously, the geometry of
the machine is important.

1624
01:18:26,930 --> 01:18:27,560
Is it straight?

1625
01:18:27,560 --> 01:18:31,190
Is it square that's
sort of thing.

1626
01:18:31,190 --> 01:18:33,440
So let me finish
up by just saying

1627
01:18:33,440 --> 01:18:37,700
that we can have this
model and then talk about--

1628
01:18:37,700 --> 01:18:39,550
and why did I bother doing this?

1629
01:18:39,550 --> 01:18:41,390
I mean it's kind of fun.

1630
01:18:41,390 --> 01:18:44,120
It's intellectually
stimulating a little bit.

1631
01:18:44,120 --> 01:18:46,550
But I think there's one
real benefit to it, which is

1632
01:18:46,550 --> 01:18:51,020
to understand why things vary.

1633
01:18:51,020 --> 01:18:55,250
So if I just say, all right,
I'm going to subdivide all--

1634
01:18:55,250 --> 01:18:59,370
by the way, all
four of these things

1635
01:18:59,370 --> 01:19:03,810
our subdivisions of this
vector alpha that we said

1636
01:19:03,810 --> 01:19:07,470
is what makes everything happen.

1637
01:19:07,470 --> 01:19:08,405
So I've got alpha.

1638
01:19:08,405 --> 01:19:09,780
And then I'm going
to divide that

1639
01:19:09,780 --> 01:19:12,420
into what I'll call
equipment states, equipment

1640
01:19:12,420 --> 01:19:16,300
properties, material states,
and material properties.

1641
01:19:16,300 --> 01:19:18,450
And why do I bother to do that?

1642
01:19:18,450 --> 01:19:19,200
Well, in the end--

1643
01:19:19,200 --> 01:19:20,730
I'll give you the punch line
because we're just about

1644
01:19:20,730 --> 01:19:21,690
out of time--

1645
01:19:21,690 --> 01:19:28,040
is some of these are really
easy to control, to keep fixed,

1646
01:19:28,040 --> 01:19:32,100
and to basically know
deterministically.

1647
01:19:32,100 --> 01:19:35,490
Most of them,
certain categories,

1648
01:19:35,490 --> 01:19:37,800
are really hard to do that with.

1649
01:19:37,800 --> 01:19:42,840
As an example, material
properties, yeah,

1650
01:19:42,840 --> 01:19:45,420
material property
of this, how well

1651
01:19:45,420 --> 01:19:48,090
do I know the properties
of this bar of aluminum

1652
01:19:48,090 --> 01:19:50,730
or this hunk of plastic?

1653
01:19:50,730 --> 01:19:53,740
Well, I can do some tests
and do this kind of stuff.

1654
01:19:53,740 --> 01:19:55,440
But, again, it can
be shown that these

1655
01:19:55,440 --> 01:19:57,450
can be highly
variable, particularly

1656
01:19:57,450 --> 01:20:00,400
as I go from this bar
to that bar to that bar.

1657
01:20:00,400 --> 01:20:04,200
So we're going to be able to
argue that unless you spend

1658
01:20:04,200 --> 01:20:06,690
a lot of time upstream
eliminating variations,

1659
01:20:06,690 --> 01:20:14,370
like unless you do really good
process control on the casting

1660
01:20:14,370 --> 01:20:16,500
and rolling and other
processes that go into,

1661
01:20:16,500 --> 01:20:19,630
this will have
variable properties.

1662
01:20:19,630 --> 01:20:23,940
So this tends to be--
material properties

1663
01:20:23,940 --> 01:20:27,030
tends to be variable.

1664
01:20:27,030 --> 01:20:32,030
And as a result, depending
on the process mechanics,

1665
01:20:32,030 --> 01:20:37,010
has a huge effect on
what your result can be.

1666
01:20:37,010 --> 01:20:39,830
Unless-- there are some
wonderful processes out there,

1667
01:20:39,830 --> 01:20:42,570
again, like I said, like
machining, that say,

1668
01:20:42,570 --> 01:20:43,560
I don't really care.

1669
01:20:43,560 --> 01:20:45,410
I'm very insensitive to that.

1670
01:20:47,990 --> 01:20:52,460
Equipment properties--
equipment property,

1671
01:20:52,460 --> 01:20:57,020
so the stiffness of the machine,
the temperature in a reaction

1672
01:20:57,020 --> 01:20:58,820
chamber, other
things like that--

1673
01:20:58,820 --> 01:21:00,020
I'm sorry, not temperature.

1674
01:21:00,020 --> 01:21:06,860
Sorry, the thermal insulation
in an oven, something like that.

1675
01:21:09,520 --> 01:21:12,162
Within limits, of course,
there's some uncertainty there.

1676
01:21:12,162 --> 01:21:13,120
It's not just variable.

1677
01:21:13,120 --> 01:21:18,850
I should say variable
or uncertain.

1678
01:21:18,850 --> 01:21:22,570
Either one is a source of
uncertainty or variation

1679
01:21:22,570 --> 01:21:23,070
for us.

1680
01:21:26,550 --> 01:21:28,950
Equipment properties, well,
again, if I pay a lot,

1681
01:21:28,950 --> 01:21:31,290
I'm careful with
the machine, if it

1682
01:21:31,290 --> 01:21:34,750
doesn't degrade a lot over
time, then I'm in good shape.

1683
01:21:34,750 --> 01:21:36,160
Machines degrade over time.

1684
01:21:36,160 --> 01:21:40,320
So tool wear is a degradation
in an equipment property.

1685
01:21:40,320 --> 01:21:41,850
It's an expected
dimension that's

1686
01:21:41,850 --> 01:21:44,140
actually changing over time.

1687
01:21:44,140 --> 01:21:53,145
So this can be variable
over, many cases, long times.

1688
01:21:53,145 --> 01:21:55,520
And that's a maintenance issue,
as much as anything else.

1689
01:21:55,520 --> 01:21:58,255
But again, that's within
a question of how good

1690
01:21:58,255 --> 01:21:58,880
the machine is.

1691
01:21:58,880 --> 01:22:02,120
If you build a machine
with very sloppy bearings,

1692
01:22:02,120 --> 01:22:05,718
a sloppy bearing is
basically a noise generator.

1693
01:22:05,718 --> 01:22:07,260
You just don't know
where things are.

1694
01:22:07,260 --> 01:22:10,350
If you build a machine that is
supposed to distribute a vapor

1695
01:22:10,350 --> 01:22:14,750
and it's got some sort of
a vapor handling system

1696
01:22:14,750 --> 01:22:18,050
that's supposed to distribute
it evenly, but it clogs easily

1697
01:22:18,050 --> 01:22:21,260
or something like that, or it
just wasn't designed properly,

1698
01:22:21,260 --> 01:22:24,080
then you've got bad properties.

1699
01:22:24,080 --> 01:22:26,095
It could cause variability.

1700
01:22:29,980 --> 01:22:37,950
Equipment states-- forces,
pressures, temperatures, flows,

1701
01:22:37,950 --> 01:22:40,980
velocities, what do
you think about those

1702
01:22:40,980 --> 01:22:43,770
in terms of our ability to
control those and eliminate

1703
01:22:43,770 --> 01:22:44,850
uncertainty?

1704
01:22:44,850 --> 01:22:46,493
Good, bad, or indifferent.

1705
01:22:50,437 --> 01:22:52,410
AUDIENCE: Good.

1706
01:22:52,410 --> 01:22:54,070
DAVID HARDT: Good.

1707
01:22:54,070 --> 01:22:57,040
We have a vote for good.

1708
01:22:57,040 --> 01:23:00,220
I would opine that any machine
built in the past 20 years,

1709
01:23:00,220 --> 01:23:02,320
at least, it's really good.

1710
01:23:02,320 --> 01:23:06,490
And that, if you will, is the
victory of CNC type controls,

1711
01:23:06,490 --> 01:23:07,420
of computer controls.

1712
01:23:07,420 --> 01:23:10,060
One of the biggest things
is that this is now

1713
01:23:10,060 --> 01:23:17,840
very minimal, minimal
variation or uncertainty.

1714
01:23:17,840 --> 01:23:22,190
I know exactly-- if I have
a good Servo and I say,

1715
01:23:22,190 --> 01:23:25,320
go to this velocity, it
goes to that velocity.

1716
01:23:25,320 --> 01:23:27,620
If I have a good
temperature regulator

1717
01:23:27,620 --> 01:23:29,060
and I say go to
this temperature,

1718
01:23:29,060 --> 01:23:31,940
it'll hold that easily
within a degree,

1719
01:23:31,940 --> 01:23:34,470
and in some extreme cases,
a lot less than that.

1720
01:23:34,470 --> 01:23:37,520
So particularly with the
use of active control,

1721
01:23:37,520 --> 01:23:40,280
we've made that really good.

1722
01:23:40,280 --> 01:23:42,470
So the last one--

1723
01:23:42,470 --> 01:23:47,700
and I would say end
controllable, in other words,

1724
01:23:47,700 --> 01:23:49,820
not only is it not
variable, I can actually

1725
01:23:49,820 --> 01:23:53,400
tell you what I want it to be.

1726
01:23:53,400 --> 01:23:56,120
So I'm going to skip discussion
of the material states,

1727
01:23:56,120 --> 01:24:04,190
except to say that
they're often--

1728
01:24:04,190 --> 01:24:12,110
well, let's say they are
variable and hard to know.

1729
01:24:12,110 --> 01:24:14,900
And I'll give you my one
favorite example of that.

1730
01:24:14,900 --> 01:24:16,400
Let's say that I
have a polymer that

1731
01:24:16,400 --> 01:24:17,900
needs to be at a
certain temperature

1732
01:24:17,900 --> 01:24:20,030
to do what it's supposed to do.

1733
01:24:20,030 --> 01:24:22,940
Typical way of doing that would
be put it in an oven and let it

1734
01:24:22,940 --> 01:24:24,350
sit in that oven.

1735
01:24:24,350 --> 01:24:26,270
So the oven has
certain properties

1736
01:24:26,270 --> 01:24:28,880
that makes it keep
uniform temperature.

1737
01:24:28,880 --> 01:24:31,420
And it has a really good
temperature control on it.

1738
01:24:31,420 --> 01:24:35,000
So if I say heat this to 100
C, it's right there at 100 C.

1739
01:24:35,000 --> 01:24:37,250
So I've got this
heated air, and it's

1740
01:24:37,250 --> 01:24:42,290
at 100 C. I take a piece of
polymer, and I put it in there.

1741
01:24:42,290 --> 01:24:45,260
And I wait sufficiently long
that it's at equilibrium

1742
01:24:45,260 --> 01:24:47,090
and the polymer is now
at 100 C. And then I

1743
01:24:47,090 --> 01:24:48,882
pull it out and put it
in a warming machine

1744
01:24:48,882 --> 01:24:51,830
or something like that.

1745
01:24:51,830 --> 01:24:55,120
What's the temperature of
the polymer when I formed it?

1746
01:24:55,120 --> 01:24:57,210
That's a state of
the polymer, right?

1747
01:24:57,210 --> 01:24:59,140
It's a thermodynamic
state of the polymer.

1748
01:24:59,140 --> 01:25:01,140
I don't know.

1749
01:25:01,140 --> 01:25:03,820
Unless I measure
it, I don't know.

1750
01:25:03,820 --> 01:25:05,920
I'm not controlling it anymore.

1751
01:25:05,920 --> 01:25:07,450
Now, there are also
cases, and this

1752
01:25:07,450 --> 01:25:09,200
is true I think in the
semiconductor world

1753
01:25:09,200 --> 01:25:12,460
now more than anything else
is that if I want to control

1754
01:25:12,460 --> 01:25:16,820
a temperature, for example, I
don't measure the temperature

1755
01:25:16,820 --> 01:25:19,070
of the oven or the chamber.

1756
01:25:19,070 --> 01:25:23,630
I measure the temperature of the
thing that I'm going to make.

1757
01:25:23,630 --> 01:25:26,632
And an example of that
is-- in fact, the machine

1758
01:25:26,632 --> 01:25:29,090
that this was made on if you
guys have used this, the ENGEL

1759
01:25:29,090 --> 01:25:32,450
down in Building 35, you
control the temperature

1760
01:25:32,450 --> 01:25:34,880
usually on this
process by controlling

1761
01:25:34,880 --> 01:25:37,190
the nozzle temperature and
the barrel temperature.

1762
01:25:37,190 --> 01:25:39,770
And you say, oh, that's the
temperature of the polymer.

1763
01:25:39,770 --> 01:25:41,990
But what really matters
is the temperature

1764
01:25:41,990 --> 01:25:46,370
of the polymer in the mold,
which you never measure.

1765
01:25:46,370 --> 01:25:46,880
Right?

1766
01:25:46,880 --> 01:25:50,690
But there's actually a little
temperature sensor in the mold

1767
01:25:50,690 --> 01:25:52,372
that you can measure that.

1768
01:25:52,372 --> 01:25:54,330
And there's also a pressure
sensor in the mold.

1769
01:25:54,330 --> 01:25:56,690
So you could, if you
wanted to, actually

1770
01:25:56,690 --> 01:25:58,850
measure the pressure on this.

1771
01:25:58,850 --> 01:26:00,500
But it's hard to do.

1772
01:26:00,500 --> 01:26:03,170
So this tends to
be-- it's knowable,

1773
01:26:03,170 --> 01:26:05,600
but sort of expensive to do.

1774
01:26:05,600 --> 01:26:08,210
So here's the
moral of the story.

1775
01:26:08,210 --> 01:26:09,890
Biggest source of
variation tends

1776
01:26:09,890 --> 01:26:14,670
to be material uncertainties,
just inherent in the material

1777
01:26:14,670 --> 01:26:18,770
and, if you will, the coupling
between this energy source

1778
01:26:18,770 --> 01:26:21,710
and how well it actually
gets into the material

1779
01:26:21,710 --> 01:26:24,000
through sort of an
uncertain interface.

1780
01:26:24,000 --> 01:26:26,900
So all of these things
here, these three,

1781
01:26:26,900 --> 01:26:29,000
are your sources of
variation typically

1782
01:26:29,000 --> 01:26:30,450
in differing measures.

1783
01:26:30,450 --> 01:26:33,710
This is the one saving grace.

1784
01:26:33,710 --> 01:26:35,390
You're going to
actually control--

1785
01:26:35,390 --> 01:26:37,310
way back at the
beginning of the process,

1786
01:26:37,310 --> 01:26:40,640
you're going to control
equipment stakes.

1787
01:26:40,640 --> 01:26:45,440
So when it's all said and
done, what we manipulate here

1788
01:26:45,440 --> 01:26:48,845
are typically, not always, but
typically equipment states.

1789
01:26:51,500 --> 01:26:54,380
And our ability to do
that and how well I

1790
01:26:54,380 --> 01:26:56,720
can change an
equipment state to get

1791
01:26:56,720 --> 01:26:59,090
a change, the sensitivity
of the process,

1792
01:26:59,090 --> 01:27:01,820
has a lot to do with what
I can do with its control.

1793
01:27:01,820 --> 01:27:04,040
And the rest of the lecture,
which is in the notes,

1794
01:27:04,040 --> 01:27:06,450
is going through
these three processes

1795
01:27:06,450 --> 01:27:08,700
I've talked about and kind
of addressing those issues.

1796
01:27:08,700 --> 01:27:11,200
So if you have a chance, take
a look at the rest of those.

1797
01:27:11,200 --> 01:27:12,390
OK?

1798
01:27:12,390 --> 01:27:14,090
OK, thank you.

1799
01:27:14,090 --> 01:27:15,590
Thank you all.

1800
01:27:15,590 --> 01:27:16,880
And I won't see you next time.

1801
01:27:16,880 --> 01:27:18,580
He will.