Apple may turn to carbon fiber for lighter MacBook Air - Page 3

When the author of the original blog entry wrote this above:

"Carbon fiber is an extremely lightweight material comprised of very thin fibers about 0.0050.010 millimeters in diameter and composed mostly of carbon atoms. The atoms bond together in microscopic crystals that are aligned parallel to the long axis of the fiber and can thus be used to form exceptionally strong composites without requiring more material.

The high strength-to-weight ratio of carbon fiber has made it a popular choice for the aerospace, sporting, and racing industries, where it's used for aircraft parts, bicycle frames, and performance car bodies."

whose origins are from http://en.wikipedia.org/wiki/Carbon_fiber :

"Carbon fiber or carbon fibre[1] (alternately called graphite fiber, graphite fibre or carbon graphite) is a material consisting of extremely thin fibers about 0.00020.0004 inches (0.0050.010 mm) in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in microscopic crystals that are more or less aligned parallel to the long axis of the fiber. The crystal alignment makes the fiber incredibly strong for its size. Several thousand carbon fibers are twisted together to form a yarn, which may be used by itself or woven into a fabric.[2] Carbon fiber has many different weave patterns and can be combined with a plastic resin and wound or molded to form composite materials such as carbon fiber reinforced plastic (also referenced as carbon fiber) to provide a high strength-to-weight ratio material. The density of carbon fiber is also considerably lower than the density of steel, making it ideal for applications requiring low weight.[3] The properties of carbon fiber such as high tensile strength, low weight, and low thermal expansion make it very popular in aerospace, civil engineering, military, and motorsports, along with other competition sports."

then the writer has plagiarized and paraphrased Wikipedia without citing them.

That is unfair. Please be careful next time. ALWAYS cite your sources, even if they are General Open License, etc. etc. Otherwise you are claiming those ideas as your own, which they are not.

Rich

carbon fiber would be a very good move. Not only is it lighter, its something different than the metal scheme of the last eight years.

Absolutely. As I said in my previous reply, the original point of this all is that the _entire_ laptop shell could not be made from CF. That would make the presence of internal antennae an impossiblity, since Carbon fiber is not RF transparent.

Wow, ya think? Who writes this crap?

Ropes are used in applications of tension, not compression.



"according to DSM, it is not advisable to use UHMWPE fibers at temperatures exceeding 80 to 100 °C for long periods of time. " - Wikipedia


"DSM Dyneema is the inventor and manufacturer of Dyneema®, the worlds strongest fibre.
... It is up to 15 times stronger than quality steel and up to 40% stronger than aramid fibres, on a weight-per-weight basis. "

http://www.dsm.com/en_US/html/hpf/ho...?source=search



"Dyneema and Spectra are gel spun through a spinneret to form oriented-strand synthetic fibers of UHMWPE, which have yield strengths as high as 2.4 GPa and density as low as 0.97 kg/l (for Dyneema SK75)[5]. High strength steels have comparable yield strengths, and low carbon steels have yield strengths much lower (around 0.5 GPa). Since steel has a density approximately equal to 7.8 kg/l, this gives strength/weight ratios for these materials in a range from 10 to 100 times higher than for steel." - wikipedia

2.4 GPa is about 362.6 ksi I believe, giving Dyneema a tensile strength about 45% greater than the stainless steel you mention.

I love when threads get so technical I have nary a clue of what the hell it's about. It gives me something to research. Keep it up!

Nice try, but ...

I spent three years of R&D on a military project involving the use of high tenacity fibers.

So I know the real answers, not what is published as PR from DSM.

1) The published tenacity is ~20-30% higher than for large cross-sections of any high tenacity fiber, and this is also true for the modulus to a lesser extent, say 10-20%. The published tenacity/modulus is either a single fiber pull test or a small bundle (say 1500 denier) taken at the optimum twist angle of the fiber bundle. Commercial carbon fiber is like glass, it's good for all of one compression cycle in it's native state, that's why you only see it used as an FRP core material, this constrains/eliminates any possible bending of these fibers, the source of kink banding. Long chain polymers give all these high tenacity materials their high strength/modulus versus the native materials themselves.

2) Ropes are always considered tension elements. D'oh! However, all fibers are not under the same tensile stress, the rope goes slack, some fibers go into compression, cycled a few thousand times, kink banding occurs, more fibers fail over time, rope then fails. Got it? Heck, the API still does not have design guidence for high tenacity fiber ropes, it took them more than 10 years just to do PET (polyester ropes).

3) Independent peer reviewed journal papers show the real story of Dyneema's extremely poor temperature properties and linear creep properties. You won't find that type of information anywhere on the DSM website for all too obvious reasons. No one in their right mind would ever use Dyneema in a static force application. If you want a spaghetti laptop, than by all means make the superstructures out of Dyneema. Residual stresses and heat would cause the FRP material to warp over time. Guaranteed.

Any more questions?

Not sure what you're saying here, as carbon fiber is not plastic. Methods of production do not use high temperatures like that. nothing even remotely close.

Grinding carbon fiber composites serves no purpose as there is no real use for it.


Believe what you want, but it is better. Aluminum production is well understood. Recovery of almost 100% of the initial metal, and cutting fluids, is possible, at a far lower cost in energy than the initial production. Other savings include the lack of molds, and stamping. That has large energy requirements. A simplification of manufacturing. That saves energy all around. Even if the computer case is thrown away in a landfill, the aluminum has no toxic effect as plastic can, as it breaks down.


Not quite. Plastic has environmental consequences beyond that of initial energy use. You can't burn plastic as fuel, or for any other purpose. burning most all plastics results in various toxic chemicals, and carcinogens, being released. Carbon sequestering would be required as well, because the largest part of any plastic is carbon. We can all guess as to what the most important component to carbon fiber sheets would be. Under high temperatures, it breaks down into soot, and other carbon compounds such as carbon monoxide, etc. Depending on the exact nature of the plastic, and there are many kinds of blended materials, you could get dioxin, which is produced from plastics that contain chlorine (hence the removal of PVC). Quite a few other toxic chemicals, really too numerous to list, are produced.

So no, plastic is NOT a better material environmentally.
[/QUOTE]

There was a comment that stated that CF is not RF transparent. Is that true?

I work on the 777 at the Boeing plant in Everett, Washington. You forgot the floor beams, the floor panels, the radome and most of the galley and Lavs are all made of CF. Only about 25% of the 777 is made from CF. Now I am thinking that folks are thinking about the 787 and it is about 60-70% CF, including the main airframe is CF barrels along with the wings.

I can only imagine that if Apple does indeed design their own cases, as well as the huge number of parts required for any product, that they must have a large number of ME's working for them. You simply can't do this any other way.

If all they do is to make sketches, and send all of that work out, then that's different. But I don't see them doing that, do you?

In fact, it's used as an RF shield.

If it weren't still so expensive, it would make a better Faraday cage than the copper mesh which is usually used now.

Frank, the problem is that unless you can give references as to those numbers, they aren't tenable.

I recently had a discussion with a guy, where I mentioned that the population of NYC proper was a bit over 8 million. He said that I was wrong, and that it was 14 to 15 million. I asked him if he meant the Greater New York Area, which is indeed about 14 to 15 million. He said, no, the 5 boroughs.

I told him that his number was wrong, and asked how he got his. After giving me generalized numbers about what he though were reasons, traffic, subway crowding, immigration, etc., I still didn't agree.

Then he pulled a fast one. He said that I was naive. Ok! I've been called worse.

But then he said that he knew, because he sat in on secret governmental committees that used to set these numbers for public consumption!

Right!

The point to this is that something said that can't be shown because it isn't available to us, isn't proof. It's just the statements of one person.

While I can't always find the information on the web for something I know to be true, even if the page was there before, it's difficult to use unpublished information in a discussion. There is no reason why someone would want to believe it, when undisputed published numbers are available.

I'm not saying that I don't believe you, just that we have to take your word for it in the face of actual numbers. I'm sure some test results are available.

Very much so.

I would have though it would be. Thanks for the reply. Is their a quick and dirty answer as to why the carbon prevents RF to pass?

The molecules are aligned such that RF (err EM) will not pass normal to these aligned molecules. Normal to the surface of the carbon fiber FRP.

The appeal to authority is valid in this case, as I'm a SME in this area, among many other areas of science and engineering and analysis and etceteras.

All the information I've mentioned can be found in the peer reviewed engineering and scientific literature. Or more than one of several PhD theses of DSM employees or other independent investigators. That's a given. Because that is where I found it. Any SME in this area of expertise would agree with me 100% of the time, on my previous statements wrt Dyneema. SME's at DSM would not agree, for the obvious reason of institutional bias.

Also, I happen to be a polymath.

I don't need or care if anyone believes me.

To really oversimplify, it's the high conductivity at high frequencies that is responsible. That's REALLY oversimplifying. A part of the reason, is also the length to the width of the strands. That's called the percolation threshold. That helps to "short circuit" the radiation.

This is similar to the way aircraft are made to be transparent to radar. instead of reflection most all of the energy back, they absorb much of it, only needing to reflect a small part away from the source, which is much easier.

Older shielding made of metal copper, or copper alloy (sometimes in less critical applications, aluminum) mesh or film, relies on reflection.

Mind you Frank, I'm not disagreeing with your statements made earlier, just saying that it's what you do to me when I make a statement you don't agree with.

I heard they were going to make it out of hydrogen..

Well, at very low temperature and very high pressure hydrogen becomes a metal.

Sooo, I guess it's possible if you want to use it somewhere in the center of a cold neutron star.

What are talking about? The impact resistance of CF is much greater then on other materials. I know as I have worked on CF for the last 25 years and the in fact I am currently employed at Boeing. I have worked with CF from the C-141 to the F15, F16, 747, 767, 777, 737 and some on the 787.

The main reason one is not to touch a unfinished (not painted) CF surface is the oils in your hand will cause fisheye in the finish (painted surface)

I have seen engineers from the Air Force and even at Boeing take hammers to test pieces of CF and hit them as hard as they caould and there was no damage from the strike after X-ray testing.

Tell me another story.....

Sounds awfully empty to me, because I would think that posting to a community where everybody thinks you're just crazy wrong would be just a total waste of time. Why do you post? Just to waste a little time while at work?

You didn't give a decent reason for why you don't think Apple has any ME personnel. I would like to see a bit of reasoning or clues that could lead a reasonable person to such a conclusion. I'm not asking for proof that would stand up in court, just something that can give me better insight as to why you would say that.

I provided SME knowledge. This is the internets, you should be able to read through that closing comment.

Read this again. IMHO. I never claimed that it was an objective opinion, an opinion is an opinion is an opinion. What don't you understand about someone's opinion?

Numerous design flaws across Apple's product line throughout it's history, strongly suggests that Apple has little interest in true industrial strength design.

Making something look pretty, isn't the same as a good design and built from a structural standpoint. When you place pretty in front of a well built design from an ME first standpoint you're bound to have design flaws.

I'll take something structurally designed by an engineer any day versus something structurally designed by an architect/artist.

Fortunately, Apple makes only small dimensional things relative to most ME or CE designs, the structural aspects of all Apple products, by this very nature is an afterthought, if even that, IMHO.

Cutting something from a block of metal? That's been around as long as there have been machinists and machining tools. That's real innovation or out of the box thinking on Apple's part?

TYVM.

We don't believe that.

We don't believe you.

Apple is already shipping an aluminum notebook at 13". It's called a MacBook. As such you're not going to get a 12" machine. Not enough differentiation.

I suspect that instead of a "netbook" we're soon going to see an iPad. An oversized iPod Touch.

too confusing a name for Boston residents

There is a difference between "I like red" and "I don't think Apple really has mechanical engineers" (paraphrasing there, sorry). The first, subjectivity is all there is to it. The second, I don't think it's unreasonable to be able to explain why or give a decent objective example or two, to show that you're not just trying to cause a controversy. I don't see how it is unfair to apply such a standard here, after all, you are saying you do have some form of credentials here, it shouldn't be hard to apply a bit of objectivity if you do actually have such credentials.


What specific examples of mechanical engineering flaws do you remember?

I don't think Apple is out to make Toughbooks. Even then, Toughbooks aren't necessarily all that either, the only ones that are are the ones that look like a rubberized tank. That said, Apple's notebooks are pretty tough in my experience. A toddler walked across my MBP keyboard and it's not been hurt it at all that I can tell. I've even dropped it, about a meter or so onto hardwood, no dings, scratches or apparent or functional damage. Not a lot of consumer electronics can take that. Not necessarily high standards, but then, I didn't expect combat standard here, did pretty well as far as I'm concerned.

2 things.

1. A 12" notebook that has a very little bezel and edge to edge keyboard has a significantly smaller footprint than a 13" macbbok or Air.

2. The old 12" powerbooks were great sellers for Apple, while the macbook air is a complete dud.

The bezel size has nothing to do with diagonal display size. You can make the bezel as wide or as thin as you wish. Apple's bezels seem to have gotten slightly wider, but since they are lessening out out the lid thickness, it stands to reason that this is to increase strength and rigidity of the lid.

Furthermore, the 12" model doesn't work anymore since we've shifted from a 4:3 ration to 16:10 ratio. The 13" MB and MBA displays are actually slightly shorter than the old 12" PB displays. Since widescreen is in, moving to a 12" display would make the viewing of text pages even more difficult as the vertical height would now be a inch less than before.

12" @ 4:3
• Width: 9.59"
• Height: 7.21"
• Image area: 69.14 sq. in.

13" @ 16:10
• Width: 11.02"
• Height: 6.89"
• Image area: 75.93 sq. in.



You'll have to supply evidence of both of those for me to buy it. In the nearly 4 years since the last 12" PB was released Apple's PC marketshare has increased so much that I would wager than even the niche MBA is better unit-to-unit seller than the 12" PB ever was.

How about Firewire? Apples has been recommended this connecting system to hard wares. I also have some machines have to be connected with a firewire. In future, can this lightest machine get a firewire to connect any other machines? How should I do for upgrade to the lightest one?

That is true. A Macbook Air would be noticably smaller if it didn't have those edges either. I've been saying this since it first came out. The difference wouldn't be that much different, except that new notebooks have the 16/10 screens rather than the older 4/3 screens.


THAT'S not true. The 12'vs sold well when they first came out, because they were different, but sales slowed down considerably.

The MBA is supposedly selling well to business.

Mel I tend to agree with you here but I think there are other things to be considered
before declaring aluminium to be the new saviour of the environment.

Aluminium, while abundent in the earths crust is unfortunately distributed over large areas,
which makes it very environmentally damaging to recover (almost exclusively by strip mining)
which mostly involves knocking down forests digging up the topsoil, then removing 2-3m of bauxite beneath
before trying to replace the topsoil and vegetation (with varying degrees of success wrt to flora & fauna).

Add to that the toxic chemicals (mostly hot caustic) used to recover the alumina from the bauxite
the tailings dams required to dispose of the spent caustic (not to mention the resources required to produce the caustic).

...and then there's the 50 MJ/kg of energy required to smelt the alumina powder into aluminium
energy which is often sourced from carbon burning power plants (at worst brown coal)
which put very toxic chemicals into the environment (just like the ones you're talking about in the CF - if it was ever burnt)

and all this doesn't include the cost of manufacture
(ie how much energy is required to cut the new unibodies vs that required to form a CF body).

what you've mentioned above is only the recycling / disposal part
which I agree is very much in favour of aluminium
and doesn't bode well for carbon fibre.

My opinion: if Apple want to portray themselves as environ friendly
they'd source all their aluminium from recycled sources (which is slightly better than new)
and start talking about full product cycle, not just from Apple's point of manufacture until disposal.

Thinner, lighter, thinner, lighter....
Apple has laptop anorexia. I'd take a heavier laptop with a smaller footprint (10"-11"), any day of the week! C'mon Apple where's my small net book? I'll gladly pay the "Tax"

Huh? Still trolling for an answer or two or eleventeen?

Apple is no better or no worse than all the other major computer manufacturers.

They all design small things that require little to no structural engineering analyses such as Finite Element Analysis (FEA). Heck cars, trains, ships, buildings, and etceteras were all built long before computers and without the now existing FEA codes.

Now Apple might use something like SolidWorks, to make sure there are no mechanical moving/fixed parts conflicts. But that isn't considered to be a full on structural analysis. For that you need design loads and stress analyses. By the very nature of these very small things, the design loads are obviously ill defined.

Want to build it tougher? Easy. Make everything twice as thick. D'oh! If you want to call that ME, then fine. I don't consider that ME, IMHO.

A large percentage of all metal in use today, particularly aluminum, is from recycled materials. Aluminum is very good for the purpose of recycling. It requires reletively little energy to recycle.

Much aluminum is also mined in areas where deforesttion is not much of a problem, and laws in many areas require renewal of the area with replanting. While I'm not an advocate of the use of coal for any purpose, about half the energy used in this country, and many others, is from coal now. A number of newer aluminum smelter plants use gas.

Overall, I'd rather see aluminum than some plastics, which, by the way, for people who don't know this, DO break down.

Excuse me but you seem to be trolling for something yourself.

Strength and rigidity are important numbers but are not the total story - carbon fibre is desirable because of the way it distributes forces - it doesn't dent and is quite abrasion resistant which would seem to me to be highly valued qualities in this application. the fact that Apple would look at carbon fibre suggest that there are some mechanical engineers in their midst.

Apple is a big company with a long history as a leader in industrial design - I would say they are by and large on the better side by any accounting. They have more than enough money to higher the best and brightest in any field - including plastics engineering.

To say that carbon fibre cannot be mass produced is bollocks - there are lots of carbon fibre briefcases out there which are produced in significant numbers. How many parts does an airbus have? Prepregs and vacuum bagging can be adapted to fairly high production levels. The fact that apple did the cube which is a large lucite casting says they can finesse difficult processes.

Yes hogging the chassis out of billet is not really as novel approach as Apple is trumpeting but who else is going to that length to make a lightweight and rigid computer? Any thinking engineer should salivate at the thought of such a sturdy elegant object.

The other advantage of carbon fibre is that you can sculpt the shape to a complex form derived from FEA (or practical experience - look at the DC3 if you want an example of what good engineers can do without a computer) and provide the lightest and most rigid form possible.

As to carbon fibre being opaque to RF - so is aluminum. In either case you have to design an antenna outside of the case - not that hard to do.

Yes carbon fibre is not overly recycleable but when was the last time you threw your laptop in the dumpster - most people can't do it because they remember the original cost. I suspect most go into a closet to lanquish forever or are passed on to students. It is good that people are worrying about such things but in the scheme of things it is I think small apples - materially certainly less than a pop can a week for a year.

totally agree on aluminium being perfect for recycle - and i wish more of it was

i'd like to see your sources on how much of the MB aluminium comes from recycled stock
no wait, i'd like to see apple's sources - the MB carbon costs (comparison to total costs only) are here

coming from a country which is the number 1 exporter of alumina in the world
and where mining is one of the biggest industries (and having worked in an alumina refinery as a student)
I can assure you that there are not many (in my experience none) places where bauxite is not mined without serious environmental impact
since it is invariably found on the tops of hills under trees in forests - not in the desert plains

again i'd love to see your figures for the quantity of aluminium from recycled sources
if only to reassure myself that the world isn't crazy enough to dig, refine, smelt, use, bury then dig again.

it's totally possible that aluminium can be sourced from recycled stock
but until that day it remains a very environmentally dubious material

whether or not plastic / CF is a more environmentally friendly material than aluminium
is a debate i'd love to see held in public - because it's important and i'd like to know the answer.
(however it's clear that Al is the winner from a purely recycling viewpoint)

How about some specific examples of mechanical engineering flaws in Apple products that you allude to?

You're in way over your head sonny boy.

There is nothing wrong with carbon fiber per se, I never said otherwise. I am well aware of the many current uses of carbon fiber. My critique was mainly aimed at one poster and the mention of the use of Dyneema in an FRP. Not going to happen, ever.

Also, a general lack of understanding amongst you all about in situ specific strength and modulus of high modulus fibers which are bound together through weaving and resins (most often) which reduces the strength to weight advantage by a factor of five (or more).

There is no structural design challange in making things small and light.

Apple makes pretty things, if that's what you mean by a leader in industrial design.

On the other hand, making something large and light, now that's a real structural design challange.