aluminum machining? A q that is technical but not bicyclic

Ryan Cousineau wrote:
I have a bit of an odd question with regard to laptop manufacture and
aluminum machining. It's essentially one of curiosity, but I think a few
people here may have some insight.

If you don't know, Apple just introduced some revised laptop models.
Great new features, bold design, whatever. The feature that made me sit
bolt-upright and say "no way!" was the case structure.

The old MacBook design used plastic molded cases. I think there might be
a metal inner frame, too. The "Pro" model used aluminum cases, but I'm
virtually certain they were stamped, and I think they relied on an inner
metal frame as well (depending on the year, these frames were made out
of aluminum or magnesium, I think, and presumably cast, but possibly
stamped).

This year's models are all sporting machined aluminum cases, and
apparently have no inner frame to speak of (they call it "unibody" a la
modern car designs). It appears the major components bolt more or less
directly to the body.

Web page here, including video of what may be actual manufacturing
techniques and pictures of the bare case:

http://www.apple.com/macbook/design.html

It's a clever idea, and I can see benefits. But just watch that
production video! How in the heck can they be doing CNC machining in a
production-line fashion and be cost-competitive? I would have thought
the cost and time (and manufacturing capacity?) would have been
prohibitive.

Anyone here have an insight as to how they're doing this without
spending way more money than when they were molding cases out of
plastic? I think these laptops are probably being made in the PRC,
though there's a small chance this is a Taiwanese product.

I mean, Apple's not crazy, so I assume this will all work, at least in
theory, but when did machining costs and capacities get so cheap that
they could conceive of milling out several million complex case designs
every year?


like hard drive cases, i expect they're cast to shape, then milled for
finish. machining from a solid block makes no sense.

On Wed, 22 Oct 2008 17:00:29 -0700 (PDT), Frank Krygowski
wrote:

On Oct 22, 3:44*am, Ryan Cousineau wrote:

If you don't know, Apple just introduced some revised laptop models.
Great new features, bold design, whatever. The feature that made me sit
bolt-upright and say "no way!" was the case structure.
This year's models are all sporting machined aluminum cases, and
apparently have no inner frame to speak of (they call it "unibody" a la
modern car designs). It appears the major components bolt more or less
directly to the body.

It's a clever idea, and I can see benefits. But just watch that
production video! How in the heck can they be doing CNC machining in a
production-line fashion and be cost-competitive? I would have thought
the cost and time (and manufacturing capacity?) would have been
prohibitive.

Anyone here have an insight as to how they're doing this without
spending way more money than when they were molding cases out of
plastic? I think these laptops are probably being made in the PRC,
though there's a small chance this is a Taiwanese product.

I'm surprised the chassis isn't die cast. I'd expect that would be
cheaper, and it's tolerances would be fine for that application.

CNC is great if you're doing low production things like boutique
derailleurs. It's not so economical for large production runs. And
think of the volume of scrap (chips) that they're dealing with! It
looks like over 50% of the raw material leaves as scrap.

I could be wrong, but I've got a sneaking suspicion the production
line involves something like pre-stamping or casting the aluminum into
near-final shape, then machining to the final shape. Might be a
"cheap" way to cover up for cheap casting or stamping...

As for the video, well, you ever hear of advertising?

Pat

Email address works as is.

In article
,
Chalo wrote:

Ryan Cousineau wrote:

[laptops with machined-aluminum cases.

This year's models are all sporting machined aluminum cases, and
apparently have no inner frame to speak of (they call it "unibody" a la
modern car designs). It appears the major components bolt more or less
directly to the body.

http://www.apple.com/macbook/design.html

I don't know about that. Certainly it's a lot more expensive than
making cases out of plastic, but it probably offsets thermal
management features that would add cost and would otherwise be
necessary. If you remember nice-looking CNC machined brake boosters
from Tektro and others selling for very reasonable prices even after
distributor and retail markup, you might be able to extrapolate the
fundamentally similar plate construction of the Apple laptop costing a
similar amount per area of plate, removed volume of material, etc.

That's true. But I recall those parts being pretty expensive considering
what they were, and being pretty simple machining jobs (I have a classic
purple-ano brake booster on my MTB) from pretty thin plate, and where
the nominal area would have been pretty close to the true area of those
U-shaped plates, which was awfully small. And production volumes were
almost certainly tiny compared to Apple's quantities.

So from a cost perspective, it was a smaller, simpler part where the
only real alternatives (before cheap carbon fibre) were heavier,
cruddier castings, or forgings (which were probably uneconomic at likely
production volumes). But the data point is notable.

These computer cases are competing with injection-molded plastic or
stamped aluminum, which are both cheap and fast in the volumes we're
talking about.

Make no mistake: I take it as virtually proven by the existence of these
cases that the production is viable, it just shocked me that it was so,
and wondered what it was I didn't know about these production processes.

That said, I prototyped a series of avionics component boxes once that
were machined from 9" x 9" x 2.25" blocks of aluminum. They had lots
of little ribs and small machine threads down in their bottoms, and
their wall thicknesses were reduced to 1/16". After I had vetted and
modified the original design for manufacturability, each one of these
boxes still cost on the order of $500 from an efficient production
shop with more suitable machinery than I had available to do the
prototyping. If they had only been 3/4" thick, though, they would
have been fast/easy/cheap by comparison.

These are the sort of numbers that I would have guessed at (Well, I'm
not surprised at the prototyping cost, but the CNC-production cost
surprises me a little. It is higher than I would have guessed, even for
a complex box of that size). Okay, this laptop part is a third of the
thickness, but would it have cost you less than a third the cost to make
these laptop cases using the same production process?

For high-quality, high volume CNC milling, I'd look to Taiwan first.

I'm guessing that their equation is partly a matter of being willing
to take the high road design-wise and escalate costs a little bit in
the process, and the one-piece machined case allowing them to trim
away other features and components that would have added up to some
comparable cost figure anyway.

Looking carefully at the photos and commentary in this disassembly...

http://www.ifixit.com/Guide/First-Lo...acBook-Unibody
http://www.ifixit.com/Guide/First-Lo...y/Page-7#s3006

....I find your theory compelling. It looks like the part-count is WAY
down, and it looks like the case is being used as a heat sink.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

Ryan Cousineau wrote:

That said, I prototyped a series of avionics component boxes once that
were machined from 9" x 9" x 2.25" blocks of aluminum. *They had lots
of little ribs and small machine threads down in their bottoms, and
their wall thicknesses were reduced to 1/16". *After I had vetted and
modified the original design for manufacturability, each one of these
boxes still cost on the order of $500 from an efficient production
shop with more suitable machinery than I had available to do the
prototyping. *If they had only been 3/4" thick, though, they would
have been fast/easy/cheap by comparison.

These are the sort of numbers that I would have guessed at (Well, I'm
not surprised at the prototyping cost, but the CNC-production cost
surprises me a little. It is higher than I would have guessed, even for
a complex box of that size). Okay, this laptop part is a third of the
thickness, but would it have cost you less than a third the cost to make
these laptop cases using the same production process?

Oh heavens, yes. The problem with machining those avionics boxes was
twofold: They required the use of expensive long skinny (thus
relatively flexible, thus vibration-prone) tools, and the remaining
wall thickness was thin enough to "sing" when the tool passed across
it as well as thin enough to flex away from the tool. Neither of
these things would have been a noteworthy issue with a total plate
thickness of only 3/4". A shorter, stiffer tool would have allowed
dramatically faster removal rates and better finish, and a shallower
cavity would have cleared chips better.

Aluminum plates are more expensive now, no doubt. But at Apple's
scale of production, most of the aluminum is probably carried right
back to where it came from, to be turned into more aluminum bars for
machining more computers. That's what Boeing does after machining
away roughly 95% of the mass of the aluminum plates that come into
their machine shops. (Jet airliners may have minimum skin thicknesses
of about 1.0 mm, but those skins have been machined from plates
several inches thick, with ribs and reinforcements and fastener points
carved out of solid metal.)

Chalo

On Wed, 22 Oct 2008 21:58:37 -0500, Patrick Lamb
wrote:

On Wed, 22 Oct 2008 17:00:29 -0700 (PDT), Frank Krygowski
wrote:

On Oct 22, 3:44*am, Ryan Cousineau wrote:

If you don't know, Apple just introduced some revised laptop models.
Great new features, bold design, whatever. The feature that made me sit
bolt-upright and say "no way!" was the case structure.
This year's models are all sporting machined aluminum cases, and
apparently have no inner frame to speak of (they call it "unibody" a la
modern car designs). It appears the major components bolt more or less
directly to the body.

It's a clever idea, and I can see benefits. But just watch that
production video! How in the heck can they be doing CNC machining in a
production-line fashion and be cost-competitive? I would have thought
the cost and time (and manufacturing capacity?) would have been
prohibitive.

Anyone here have an insight as to how they're doing this without
spending way more money than when they were molding cases out of
plastic? I think these laptops are probably being made in the PRC,
though there's a small chance this is a Taiwanese product.

I'm surprised the chassis isn't die cast. I'd expect that would be
cheaper, and it's tolerances would be fine for that application.

CNC is great if you're doing low production things like boutique
derailleurs. It's not so economical for large production runs. And
think of the volume of scrap (chips) that they're dealing with! It
looks like over 50% of the raw material leaves as scrap.

I could be wrong, but I've got a sneaking suspicion the production
line involves something like pre-stamping or casting the aluminum into
near-final shape, then machining to the final shape. Might be a
"cheap" way to cover up for cheap casting or stamping...

As for the video, well, you ever hear of advertising?

Pat

Email address works as is.

Dear Patrick,

It seems unlikely that Apple would lie about machining the frame from
a single rectangular block of solid aluminum and put together a video
showing the steps in detail and making specific claims:
http://www.apple.com/macbook/design.html#designvideo

If anything, Apple is boasting about going to all this fuss, which is
of little practical interest to a user--if no one told you that the
laptop case was laboriously machined out of a solid chunk of aluminum,
how would you tell without disassembling it?

Somehow I doubt that the price will be substantially lower.

The accompanying text is so absurd that it requires no comment:

"Take the thumbscoop, for example. It’s the indentation that allows
you to open the display. If the scoop is too deep, you put too much
pressure on the display to open it. If it’s too shallow, you struggle
to open the display. It may seem incidental, but if the thumbscoop is
well designed, it makes the difference between a bad experience and a
good one. The challenge of the thumbscoop was to create a crisply
machined scoop that was still comfortable to use. The designers at
Apple worked on hundreds of versions of the thumbscoop — even
examining them under an electron microscope — to get it right."

As an analogy, I'm willing to believe that someone has ceramic ball
bearings in his bicycle headset, but he has to proclaim it--otherwise,
it's not likely that anyone will notice that the ordinary grade 25
steel balls have been replaced.

Cheers,

Carl Fogel

In article ,
wrote:

On Wed, 22 Oct 2008 20:01:26 -0600, wrote:

On Thu, 23 Oct 2008 01:46:50 GMT, Ryan Cousineau
wrote:

In article ,
wrote:

On Wed, 22 Oct 2008 07:44:24 GMT, Ryan Cousineau
wrote:

I have a bit of an odd question with regard to laptop manufacture and
aluminum machining. It's essentially one of curiosity, but I think a few
people here may have some insight.

If you don't know, Apple just introduced some revised laptop models.
Great new features, bold design, whatever. The feature that made me sit
bolt-upright and say "no way!" was the case structure.

The old MacBook design used plastic molded cases. I think there might be
a metal inner frame, too. The "Pro" model used aluminum cases, but I'm
virtually certain they were stamped, and I think they relied on an inner
metal frame as well (depending on the year, these frames were made out
of aluminum or magnesium, I think, and presumably cast, but possibly
stamped).

This year's models are all sporting machined aluminum cases, and
apparently have no inner frame to speak of (they call it "unibody" a la
modern car designs). It appears the major components bolt more or less
directly to the body.

Web page here, including video of what may be actual manufacturing
techniques and pictures of the bare case:

http://www.apple.com/macbook/design.html

It's a clever idea, and I can see benefits. But just watch that
production video! How in the heck can they be doing CNC machining in a
production-line fashion and be cost-competitive? I would have thought
the cost and time (and manufacturing capacity?) would have been
prohibitive.

Anyone here have an insight as to how they're doing this without
spending way more money than when they were molding cases out of
plastic? I think these laptops are probably being made in the PRC,
though there's a small chance this is a Taiwanese product.

I mean, Apple's not crazy, so I assume this will all work, at least in
theory, but when did machining costs and capacities get so cheap that
they could conceive of milling out several million complex case designs
every year?

Dear Ryan,

Er, who said that they were spending less money to machine laptop
frames out of aluminum?

I don't know that the cases will be cheaper, but they're selling the new
model for about the same prices as the old ones, and the specs seem
competitive, too.

Given that this is one of Apple's top-three most important products,
they aren't likely to just plain blow it on manufacturing costs.

Or maybe the aluminum is a giant heat sink?

All signs point to yes.

The NeXT computer had an expensive and impractical cast magnesium case
that Jobs insisted had to be a perfect cube, without even an invisible
half degree tapering to help the manufacturing process--all painted
black.

The molds were hideously expensive, black is the worst choice for
hiding minor paint defects and resisting scuffing in shipping, and
there were one or two other little problems with the great new
features and bold design.

For some reason, perfect-cube magnesium computer cases painted flat
black failed to catch on.

Possibly that example is familiar?
http://groups.google.com/group/rec.b...4681a6bbb87dba

Indeed, but the Steve Jobs who drove the creation of the NeXT Cube has a
lot of successful, well-designed products between himself and the Cube.

I don't have to carry any water for the fruit company, but the guy does
seem to have learned a few things about manufacturing processes between
then and now.

(though what it is about Steve Jobs and cubes I don't know; the Mac G4
Cube was a notorious and exceptional failure of his latest tenure as
Apple CEO.)

Dear Ryan,

If there were some sound price or performance reason, Apple would
probably have mentioned it.

Whimsy, price elasticity, and the marketing department's demand for
something new every year seem more likely than any engineering or
budget explanations for carving laptop cases out of solid chunks of
aluminum.

I'm actually leaning towards the combination of being able to create a
stiffer, sturdier case and a much easier final assembly process (in
other words, they're spending less on assembly, and more on case-making).

Or maybe the new solid aluminum laptop case is much lighter than those
heavy old plastic cases?

I think the new computers are a bit lighter, but not much.

It may help to quote Apple's explanation:

"When you have multiple parts that are fastened together, tolerances
don’t need to be perfect. You have wiggle room, both literally and
figuratively. But when one part is responsible for many functions,
it’s critical to manufacture that part with absolute precision, down
to the micron. Every time. Millions of times over. There was only one
way to achieve this level of precision: mill the unibody from a solid
block of aluminum using computer numerical control, or CNC, machines —
the kind used by the aerospace industry to build mission-critical
spacecraft components."
http://www.apple.com/macbook/design.html

Yikes! None of that wiggle room when perfection is required! Absolute
precision, down to the micron! Just like mission critical spacecraft
components!

Heh. Early reports say the new cases feel great (solid, no flexiness).
Given what flexure does to circuit boards, that's not just an aesthetic
preference, though I have to say that my plastic MacBook is literally
creaky.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

On Oct 22, 5:00*pm, Frank Krygowski wrote:
On Oct 22, 3:44*am, Ryan Cousineau wrote:

I mean, Apple's not crazy, so I assume this will all work, at least in
theory, but when did machining costs and capacities get so cheap that
they could conceive of milling out several million complex case designs
every year?

I'm surprised the chassis isn't die cast. *I'd expect that would be
cheaper, and it's tolerances would be fine for that application.

I don't think you could cast all the detail into the
chassis at the required precision, like the holes for the
keys, and some of the support structures and ribs.
Plus screw holes. So they would need a lot of
machining after the fact.

It might have been possible to cast a sort of bowl
shaped blank and machine that, which would save
having to machine away a bunch of metal. However,
removing the large chunks of metal is probably not
the rate limiting step, because they could use a relatively
large tool and feed quickly. Machining all the small
surfaces probably takes the most time.

CNC is great if you're doing low production things like boutique
derailleurs. *It's not so economical for large production runs. *And
think of the volume of scrap (chips) that they're dealing with! *It
looks like over 50% of the raw material leaves as scrap.

As Chalo said, I imagine that the scrap is recaptured.
They probably squeeze a little of the cutting oil
out and send it off to be stamped into Dells.
Aluminum billet isn't super cheap, but the material
cost is a smallish part of the whole process.

Where I bet they are saving money is on assembly.
Conventional laptops have multiple layers of frame,
shielding, outer body and so on that can get rather
involved. Some of Apple's earlier laptops were
notoriously complex in order to cram everything into
the available space (and because they used to
discourage user serviceability). I'm typing this on an
antique iBook G3 that wishes for more disk space, but
there are over 30 steps in getting to the hard
drive. (Seriously. There are illustrated guides at
ifixit.com. I've fixed cameras that looked easier.)


Ben

In article ,
wrote:

On Wed, 22 Oct 2008 21:58:37 -0500, Patrick Lamb
wrote:

On Wed, 22 Oct 2008 17:00:29 -0700 (PDT), Frank Krygowski
wrote:

On Oct 22, 3:44*am, Ryan Cousineau wrote:

If you don't know, Apple just introduced some revised laptop models.
Great new features, bold design, whatever. The feature that made me sit
bolt-upright and say "no way!" was the case structure.
This year's models are all sporting machined aluminum cases, and
apparently have no inner frame to speak of (they call it "unibody" a la
modern car designs). It appears the major components bolt more or less
directly to the body.

http://www.apple.com/macbook/design.html#designvideo

The accompanying text is so absurd that it requires no comment:

"Take the thumbscoop, for example. It’s the indentation that allows
you to open the display. If the scoop is too deep, you put too much
pressure on the display to open it. If it’s too shallow, you struggle
to open the display. It may seem incidental, but if the thumbscoop is
well designed, it makes the difference between a bad experience and a
good one. The challenge of the thumbscoop was to create a crisply
machined scoop that was still comfortable to use. The designers at
Apple worked on hundreds of versions of the thumbscoop — even
examining them under an electron microscope — to get it right."

It pains me to admit this, but I totally get what he's talking about
with respect to the thumbscoop design, and (electron microscope
notwithstanding) I'm quite sure they prototyped multiple scoop designs
and spent a while flipping them with their thumbs.

It sounds like nonsense, but I get to put my hands on a lot of computer
equipment (including laptops) every year. In general, Apple's physical
designs are way more thoughtful than those of any other company in this
industry, and spending time fussing over the thumbscoop is a vignette
that suggests how they got there.

To an extent, yes, Apple wants to sell the idea of their own greatness,
for marketing reasons. But holy moly is their stuff nice, both on the
hardware and software side.

As an analogy, I'm willing to believe that someone has ceramic ball
bearings in his bicycle headset, but he has to proclaim it--otherwise,
it's not likely that anyone will notice that the ordinary grade 25
steel balls have been replaced.

People sometimes wonder why I work in IT support a mostly-PC environment
but have a Mac as my home laptop. I enjoy my work, and it pays well, but
I don't want to do my job at home.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

On 2008-10-23, Ryan Cousineau wrote:
In article ,
wrote:
[...]
The accompanying text is so absurd that it requires no comment:

"Take the thumbscoop, for example. It’s the indentation that allows
you to open the display. If the scoop is too deep, you put too much
pressure on the display to open it. If it’s too shallow, you struggle
to open the display. It may seem incidental, but if the thumbscoop is
well designed, it makes the difference between a bad experience and a
good one. The challenge of the thumbscoop was to create a crisply
machined scoop that was still comfortable to use. The designers at
Apple worked on hundreds of versions of the thumbscoop — even
examining them under an electron microscope — to get it right."

It pains me to admit this, but I totally get what he's talking about
with respect to the thumbscoop design, and (electron microscope
notwithstanding) I'm quite sure they prototyped multiple scoop designs
and spent a while flipping them with their thumbs.

It sounds like nonsense, but I get to put my hands on a lot of computer
equipment (including laptops) every year. In general, Apple's physical
designs are way more thoughtful than those of any other company in this
industry, and spending time fussing over the thumbscoop is a vignette
that suggests how they got there.

I can also believe they did spend a lot of time on the thumbscoop. They
are very rigorous about putting all the effort and expense into the bits
the user sees and feels and saving money somewhere else.

They must save several millions, perhaps even billions, of dollars by
helping themselves to FreeBSD-licensed software (and why not) and by only
supporting their own hardware.

To an extent, yes, Apple wants to sell the idea of their own greatness,
for marketing reasons. But holy moly is their stuff nice, both on the
hardware and software side.

Most of the software they get for free. They put their effort into the
GUI and the bits that make it nice to use. It's a good strategy,
especially for a consumer product.

On Wed, 22 Oct 2008 19:34:28 -0700, jim beam wrote:

Tom Ace wrote:
On Oct 22, 12:44 am, Ryan Cousineau wrote:

I mean, Apple's not crazy, so I assume this will all work, at least in
theory, but when did machining costs and capacities get so cheap that
they could conceive of milling out several million complex case designs
every year?

Hard disk drives have had intricately machined aluminum cases for
years.

Tom Ace


they're /finished/ with machining operations, but the bulk of the
shaping is done by casting. finish is much cheaper/simpler than forming.

Wrong again.

Apple says they start with a solid block.