Plastic laptop cases are objectively better than metallic ones. Plastic doesn't heat up your legs that much, and good carbon plastic is stronger than steel, weight-wise. Subjectively, metallic feels better though.
Only "objectively" by your priorities. The fact that metal heats up your legs is also a benefit (e.g. better heat transmission = better performance and component lifetime in the same environment).
As someone else noted, "strength" in material is not one-dimensional. Carbon plastic is still way more conducive to cracking, for one.
Ergo, there is no "objectively better" choice between metal/plastic/carbon in the general case, it comes down to preferences, priorities and requirements.
What about by volume? Also, stronger meaning what? There's a combination of factors here: not just whether it breaks, but also how (dent vs crack..). Also, how well it ages. Also, how much flex does it have and how does that affect the lifespan of the internal components?
I don't know those answers; perhaps carbon plastic wins on all metrics. It would be interesting to learn.
Usually tensile strength. For example: Tensile strength: even a commodity PA6-GF30 (most half-decent tools are made of) is ~110MPa [according to ISO 527], cast Aluminum - would be ~150MPa (22K psi for the imperial folks) depending on the alloy.
Of course, most laptops would be using an ABS blend, which is the hallmark low-quality tools.
>Dents
That would depend on the top finish, not so much of the material itself.
> That would depend on the top finish, not so much of the material itself.
Would it? If I dropped an aluminium bodied laptop like a Macbook or HP Envy, I'd expect it might scuff and slightly dent at the point of impact. If I dropped the cheapest plastic bodied thing from Currys/Walmart/whatever, I'd expect it might scuff and crack the plastic between screws or something.
What top finish would you apply to a cheap plastic laptop to make it 'ding' like aluminium instead of crack in a drop test?
I would not consider cracks "dents". I already mentioned the cheap 'ABS' plastic, they would crack (also it's not UV stable). You can look up PA6-GF30 (nylon, 30% glass fiber reinforced) tools and they survive ~2m (6 feet) drop tests. Laptops won't do that as their screens would crash. Here: a popular video[0] of some massive abuse of a multimeter.
Again, a good plastic with glass or carbon fiber reinforcement would have similar properties to al-mg body, yet feel cheap as most people consider all plastics quite the same. For example: polycarbonate, 30% carbon fiber would have tensile strength of 150MPa (which the same to cast aluminum)
No, neither would I. I was agreeing with the commenter you replied to, that I'd expect a plastic laptop to crack, and a metal one to dent. If it has to be damaged, I'd prefer the dent.
You said above that that was more to do with 'top finish' than 'material'; that's what I was responding to - how would you finish crackable plastic material to make it dent like aluminium/alloy instead.
As someone else noted, "strength" in material is not one-dimensional. Carbon plastic is still way more conducive to cracking, for one.
Ergo, there is no "objectively better" choice between metal/plastic/carbon in the general case, it comes down to preferences, priorities and requirements.