Would there be a practical problem making phones out of carbon fiber?

"Anon" (tjsielsistneb)
09/25/2014 at 12:02 • Filed to: None

With all of this news about the iphone plus bending, I'm wondering if it might be time to start using carbon fiber in phone construction. The stuff can be rigid as all hell, is light weight, and costs are starting to get reasonable. So I'm calling it, in the next 10 years carbon fiber and plastic are going to be the next big phone building material!

DISCUSSION (32)

crowmolly > Anon
09/25/2014 at 12:04

What happens when you drop it?

Logansteno: Bought a VW? > Anon
09/25/2014 at 12:04

Thanks, now I want a bare carbon fiber phone.

For Sweden > Anon
09/25/2014 at 12:04

Cost

Mercedes Streeter > Anon
09/25/2014 at 12:05

You know, there is a perfectly fine phone building material that can be made strong and is already used on phones: Plastic.

Unfortunately Apple shot themselves in the foot. They started the metal phone trend and with the iPhone 6, it may have actually reached its peak. Aluminum can only get so thin before it becomes flimsy.

Granted, they can reinforce the metal on the midframe of the unibody and it will not bend, but that would require a bit of a re-design and will lead to more weight...I figure if this becomes severely widespread they'll probably take that direction...

Anon > For Sweden
09/25/2014 at 12:06

I can order a full carbon bike frame for $300 so I would be surprised if they couldn't get it really cheap with mass production.

For Sweden > Anon
09/25/2014 at 12:07

The process is the same however; laying the sheets of fiber by hand.

Twingo Tamer - About to descend into project car hell. > Anon
09/25/2014 at 12:09

Polycarbonate works well enough on many phones, but apparently it isn't "premium" enough. Metal looks better so it continues to be used regardless. That said I have a HTC One S which is aluminium and made in much the same way as the iphone 6 and I just tried bending it, completely solid. That thing was a tank of 3310 proportions, I dropped it so many damn times and it still works.

Nibbles > Mercedes Streeter
09/25/2014 at 12:09

Polycarbonate for the win

jariten1781 > Anon
09/25/2014 at 12:11

Well, there's this:

http://www.tagheuer.com/int-en/mobile-…

Mattbob > Anon
09/25/2014 at 12:12

my razrHD from almost 3 years ago has the back made out of a kevlar weave, so I can't imagine they wont start doing it soon.

RockThrillz89 > Mercedes Streeter
09/25/2014 at 12:14

You could say the same for plastic, could you not? I know plastic has some flexibility before it creases like metal, but instead of just bending, harder plastics will just snap. Especially on a radius like where the iPhone is bending. I think the problem with the phone is there is not enough internal support. Even if it were plastic, I would think you would still see people having problems.

Assuming that is the situation, I would rather have metal bend than plastic snap. At least the metal will stay together so you can nurse it back to the POS and get it replaced. Snapped plastic would leave all the innards exposed.

Then again, I could be 100% wrong. I don't really keep up with the current state of plastic technologies, so plastic may not be a brittle as what I'm thinking in my head.

CAcoalminer > For Sweden
09/25/2014 at 12:17

There's also injection molding.

JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t > Mercedes Streeter
09/25/2014 at 12:17

Yup, my Lumia 928 is made of plastic and that thing is tough as nails.

Arch Duke Maxyenko, Shit Talk Extraordinaire > Anon
09/25/2014 at 12:17

Carbon fiber composites can be stiff as hell, but they still want to bend. It's what gives it such great strength, it has the ability to bend and flex, but not crack.

Mercedes Streeter > RockThrillz89
09/25/2014 at 12:20

Well engineered plastic will be flexible enough to take whatever forces your pocket will give it...Polycarbonate is such a plastic. It's tough, flexible, and has an indefinite lifespan.

Granted, you'll still find people figuring out how to make the plastic fail (too much heat, too much cold, etc) but generally speaking, Polycarbonate will not suffer from the same bending issues.

BmanUltima's car still hasn't been fixed yet, he'll get on it tomorrow, honest. > CAcoalminer
09/25/2014 at 12:26

How would you injection mold carbon fibre?

PS9 > Anon
09/25/2014 at 12:27

Carbon fiber with the properties you want won't cost effectively scale well in a mass produced thing like an iPhone.

CAcoalminer > BmanUltima's car still hasn't been fixed yet, he'll get on it tomorrow, honest.
09/25/2014 at 12:33

spanfucker retire bitch > JawzX2, Boost Addict. 1.6t, 2.7tt, 4.2t
09/25/2014 at 12:43

Yeah, my Lumia 920 and 1520 are built like fricken tanks.

uofime > RockThrillz89
09/25/2014 at 12:48

the young's modulus of commonly used aluminum alloys (eg 6061) is greater than the modulus of any plastic, even glass filled ones (eg Ryton R4-200 40%GF)

which means that aluminum is stronger than plastic size for size absolutely.

the biggest issue with the new iphone and all new phones is that as the become thinner their stiffenss is reduced purely by geometric constraint. the stiffness is related to the youngs modulous and the polar moment of inertia, if you model the phone as a solid rectangle for simplicity the moment is Bh^3/12 h being the thickness and B the area.

it should be clear that making the phone thin is the problem here and there's not a helluva lot you can do about it

GTI Sprinks > Anon
09/25/2014 at 12:58

Please never trust your life (or teeth, more likely) to a $300 carbon fiber bike frame. What's that saying about "too good to be true?"

BmanUltima's car still hasn't been fixed yet, he'll get on it tomorrow, honest. > CAcoalminer
09/25/2014 at 13:01

That's glass fibre, carbon fibre is made in a completely different manner

Steve in Manhattan > Mercedes Streeter
09/25/2014 at 13:06

I have the plastic 5C (C for cheaper) in Kermit the Frog green. With a Lifeproof case for added heft. I love it.

Jayhawk Jake > Anon
09/25/2014 at 13:15

Carbon composite is pretty poor at impact resistance. One drop and your phone is busted completely.

Plastics are way the hell cheaper.

Jayhawk Jake > BmanUltima's car still hasn't been fixed yet, he'll get on it tomorrow, honest.
09/25/2014 at 13:17

You can pultrude it

This is how fiber rods and tubes are made. You could make a square then chop it in half.

Zipppy, Mazdurp builder, Probeski owner and former ricerboy > Mercedes Streeter
09/25/2014 at 13:36

I've been using HTC for a while, and they seem to do aluminum casings right. My One M7 is 9.3mm thin, and it doesn't feel like it'll snap or bend, like the iPhone 6 +.

Mercedes Streeter > Zipppy, Mazdurp builder, Probeski owner and former ricerboy
09/25/2014 at 15:33

That is true! The HTC One is probably the strongest aluminum cased phone on the market. It's designed like a vault. Unfortunately, they're also the most impossible phones on the market to repair as well...(they fixed that somewhat with the new version of the One M8)...

Axial > Anon
09/25/2014 at 22:36

Bending is not even a legit concern for the industry as a whole. Apple just failed to do its homework, that's all. They could use a thicker aluminum, use plastic, use kevlar (Motorola uses Kevlar sometimes), etc.

This unstoppable march for ever thinner phones is honestly ridiculous.

gogmorgo - rowing gears in a Grand Cherokee > Arch Duke Maxyenko, Shit Talk Extraordinaire
09/26/2014 at 11:52

I'm gonna say false to that. Carbon fiber may be somewhat flexible, but it's pretty seriously brittle. Get one tiny little crack, and the whole thing explodes. And yes, they will crack. Source: I've driven a car with CF suspension links. Some of them have been cracked cause someone leaned on them, or cause someone dropped them onto the workbench. And once they're on the car, you lose one link, and suddenly the entire wheel and hub assembly is held on by the brake lines cause the rest of the links also exploded.

Arch Duke Maxyenko, Shit Talk Extraordinaire > gogmorgo - rowing gears in a Grand Cherokee
09/26/2014 at 12:23

Here is a carbon fiber frame compared to an aluminum frame in stress and impact testing.

Notice how much more carbon fiber will deflect and return back compared to the aluminum. You can sit there all day flexing a piece of carbon fiber and it will not break, where as aluminum will instantly deform and start to get microcracks in it's structure, and steel will work harden until it cracks.

gogmorgo - rowing gears in a Grand Cherokee > Arch Duke Maxyenko, Shit Talk Extraordinaire
09/26/2014 at 16:20

That video offers no practical comparison between aluminum and carbon fiber as a building material. If the aluminum used in the bike frames was anywhere near as thick as the CF used, the bike frames would be just as resilient (if not more so), only a shit ton heavier. And once the carbon starts to crack, it's all over, vs the aluminum, which would just bend. An exact copy of the iPhone Plus with CF instead of Al would shatter under the stress that bends the aluminum. Either way, you'd end up with a broken phone, and I'm sure that customers would prefer the bent aluminum to a carbon one that shattered into a bunch of jagged ends. In order to prevent the bending iPhones with carbon, you'd need to make the phone much fatter than it is. You'd be better off just using slightly more aluminum.
Again, this comes from experience working with CF and aluminum in a racing setting. Sure, the aluminum doesn't hold its own shape as well as CF does (in that it's more likely to bend and stay bent) but bending is usually better than straight-up shattering. As an example, the racing series I've been involved with doesn't allow the use of carbon fiber for chassis close-outs (i.e. body panels that protect the driver) because thrown rock could hit the carbon, shatter it, and the rocks could keep going and strike the driver. Aluminum body panels may get dents and deflect somewhat, but it's far better than shattering.

Tohru > Anon
09/26/2014 at 17:43

A CF bike frame requires much less microprecision in its manufacture than a phone frame.