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Aluminum Alloy: What were they thinking?

O

odedia

macrumors 65816
Original poster
Nov 24, 2005
1,048
158
Hi,

I am wondering about Apple's decision to use Aluminum on their laptops. Aluminum is a heat conductor (it transmites heat), and by doing so, it is not such a good idea for a laptop where you really wanna keep things cool. It seems evidant now that this might have been a mistake, due to all the complaints that the Macbook Pro is really REALLY hot, some go as far as saying that at certain points it is hard to touch it.

And it makes sense. a hotter CPU (believe it or not, since it is still much more powerful than the G4), a hotter GPU, add the 7200RPM hard drive and a very very slim form factor to the equation, and you've got yourself an oven. solutions from other companies included high quality plastic (HP), magnesium alloy (Dell) and Carbon Fiber (Acer, Asus). All those materials are not heat conductors.

I am hoping for use of better materials for the next generation of laptops from Apple, ones that will match their new power-hungry platrorm.

From Wikipedia:

"Aluminium is a good heat conductor which is why it is used to make saucepans."

Oded S.
 
Making the PB out of a heat conducting metal effectively makes the computer a big radiator to dissipate heat, making the need for noisy fans less necessary. Sure the effect is that the computer gets warm, but I've never known my PB to get too hot to handle.

That said, I do go to bed with it at night instead of a hot water bottle.
 
dr_lha said:
Making the PB out of a heat conducting metal effectively makes the computer a big radiator to dissipate heat, making the need for noisy fans less necessary. Sure the effect is that the computer gets warm, but I've never known my PB to get too hot to handle.

That said, I do go to bed with it at night instead of a hot water bottle.
Click to expand...

Thats what I wanted to write, but you've been faster a couple of minutes..
 
The aluminium conducts heat away from the mbp, in order to cool it, plus, who want some plastic thing that still gets hot when they can have a sleek aluminium mbp. never underestimate the power of super aesthetics!


you are quick dr_lha! wow
 
odedia said:
Hi,

I am wondering about Apple's decision to use Aluminum on their laptops. Aluminum is a heat conductor (it transmites heat), and by doing so, it is not such a good idea for a laptop where you really wanna keep things cool. It seems evidant now that this might have been a mistake, due to all the complaints that the Macbook Pro is really REALLY hot, some go as far as saying that at certain points it is hard to touch it.

And it makes sense. a hotter CPU (believe it or not, since it is still much more powerful than the G4), a hotter GPU, add the 7200RPM hard drive and a very very slim form factor to the equation, and you've got yourself an oven. solutions from other companies included high quality plastic (HP), magnesium alloy (Dell) and Carbon Fiber (Acer, Asus). All those materials are not heat conductors.

I am hoping for use of better materials for the next generation of laptops from Apple, ones that will match their new power-hungry platrorm.

From Wikipedia:

"Aluminium is a good heat conductor which is why it is used to make saucepans."

Oded S.
Click to expand...

Go buy a Dell, HP or a Acer, then.

Problem solved.

That will be 10 cents, please.
 
dr_lha said:
Making the PB out of a heat conducting metal effectively makes the computer a big radiator to dissipate heat, making the need for noisy fans less necessary. Sure the effect is that the computer gets warm, but I've never known my PB to get too hot to handle.

That said, I do go to bed with it at night instead of a hot water bottle.
Click to expand...

Exactly. I'd rather have the heat dissipated to the case and out rather than just having the chips sit their sweating it out.

Think about it, if you can feel a lot of heat on the case that means there's a lot of heat that IS NOT in the chip. Would you really rather take all that heat and keep it in the CPU?
 
As many people here have said, I will reiterate. Designing a device to properly dissipate heat requires a decision to choose a material that does just that. Some laptops are designed with high power fans because their surface material (a thick plastic, for instance) has a low thermal conductivity value. That said, a laptop with an aluminum casing requires less fan power (or a slightly less fan power with a higher processor ceiling) because it conducts heat better and thereby releases it into the surrounding atmosphere.

odedia, your logic is actually reversed, then. Since aluminum is an effective conductor of heat, that feature makes it a prime choice for a laptop housing.

My quarrel with aluminum [as a laptop case] is that it "pits" when it is not cleaned properly. The oils from the human hand, over time and a level of contact and saturation, diminishes the natural anti-oxidation abilities of aluminum and creates weakened spots in the material. I've consistently used iKlear, so far, on my PowerBook and it is still looking new; I'm glad there are ways of dealing with that specific issue.
 
Only thing that I dislike about the casing of powerbook is that it dents easily.
Other than that, I don't see any problem at all.
 
MacHarne said:
diminishes the natural anti-oxidation abilities of aluminum
Click to expand...
Erm, aluminum naturally oxidizes. Whenever it's exposed to air, it forms a thin layer of aluminum oxide. Apple uses anodized aluminum, which creates a thicker than normal layer of aluminum oxide, making it stiffer. The acidity and salt in the oils on your skin that cause it to corrode.
 
Interesting responses, guys (except iGary's ofcourse, :S), I am begining to understand your point of view.

However, you can't ignore the fact that there are indeed complaints of the case being very very hot (much more than the powerbook, dr_lha, just check out some of those threads). Look at the forums here on macrumors, amazon user reviews and apple discussion boards. perhaps at some point, too much heat becomes a problem when dealing with the aluminum? in effect, it's understandable that starting a some degree, the heat from within heats faster than the aluminum can cool itself.

Oded S.
 
odedia said:
solutions from other companies included high quality plastic (HP), magnesium alloy (Dell) and Carbon Fiber (Acer, Asus). All those materials are not heat conductors.
Click to expand...
Some serious misconceptions here. All materials conduct heat, to a greater or lesser extent. Magnesium alloys are probably very similar to aluminium in this respect. As others have rightly said, a metal will conduct heat away from the internal components, and radiate it effectively to the surrounding air. Plastics would be less effective at doing this, and would result in a greater build-up of heat inside the case.
The aluminium used by Apple is not a pure metal, it is an aluminium alloy of some sort. Pure aluminium would be much too soft. Anodising the surface does not increase strength to any perceptible degree, it merely provides protection from natural oxidation and attack by acid (found in sweat), salt solution (also sweat, and the cause of electrolytic corrosion) and alkalis (found in soap products). So, washing your hands before using your PB might easily be just as damaging as leaving them dirty, if you don't rinse and dry thoroughly!
The anodic coating can vary from 5 to 120 microns in thickeness, 25 to 50 microns being the usual range. It increases the surface hardness (an indication of scratch resistance), but not the tensile strength. It will considerably reduce the fatigue strength (ability to resist continual stress reversals, eg bending back and forth).
All in all, I would say its a good choice for a laptop enclosure, especially from the heat point of view. It will show signs of wear after a while, especially if its abused, and will dent with an impact. Plastics will usually split or crack with a severe impact blow and also suffer from fatigue stress cracks, as many broken-hinged iBook owners can tell you.
 
The fact that when a PowerBook is left to sleep for about 10 minutes, it then becomes ICE COLD, is enough proof that it dissipates heat effectively.

Rich.
 
stevep said:
The anodic coating can vary from 5 to 120 microns in thickeness, 25 to 50 microns being the usual range. It increases the surface hardness (an indication of scratch resistance), but not the tensile strength. It will considerably reduce the fatigue strength (ability to resist continual stress reversals, eg bending back and forth).
Click to expand...

Wow, you're brilliant. :eek:

odedia said:
However, you can't ignore the fact that there are indeed complaints of the case being very very hot (much more than the powerbook, dr_lha, just check out some of those threads).
Click to expand...

The Rev. A aluminum PowerBooks were just as bad. Later on they became much, much cooler, mostly from advances in the chip design and other components. I don't know enough about Core Duo to say much here, other than we can reasonably expect later revisions to be cooler.
 
iGary said:
Go buy a Dell, HP or a Acer, then.

Problem solved.

That will be 10 cents, please.
Click to expand...

If someone say one negative thing (if at that) about Apple, someone almost always reply "buy a Dell then." How old are you?
 
Perhaps the reason that people reply to Apple criticism with "Go to Dell", is that basically, most of the barbs that get lobbed at Apple products seem to be based on non-linear comparison with other brands of computers. A computer is merely a modern day hammer (an extension of the brain, much as the hammer is an extension of the fist). No computer is perfect in every way. It does register within my dense cranial matter that much of the technology that filters down into the Wintel world was birthed and reared as a child with a Cupertino address. The brand loyalty to Apple is not something that happened by mistake. Apple is more than OSX, more than iPod and iTunes. To get back on topic, Heat dissipation is a grand consideration to hardware developers, who are pushing the envelope in more directions than ever. YES, there are complaints about the heat of the MBP, but I have heard of PB's catching fire, iPods blowing up, and iMacs that seem to jump from balconies. So if my denim starts smoking, I will put the notebook on a suitable support device (like a table..), or shut it down for a bit and give it, and myself a much deserved bit of rest. aluminum alloy would seem to be the most cost effective solution. Maybe we could get an actual engineer from Apple development to answer the question, and we'll really know what they were thinking.
 
maverick808 said:
Exactly. I'd rather have the heat dissipated to the case and out rather than just having the chips sit their sweating it out.

Think about it, if you can feel a lot of heat on the case that means there's a lot of heat that IS NOT in the chip. Would you really rather take all that heat and keep it in the CPU?
Click to expand...

Which do you care more? Your hands or CPU?
 
I personally hate the "go buy a Dell" crap that gets lofted around ALL Mac forums. Personally, I love Apple's computers but I have no problem with people expressing an opinion that could make them better (such as a less-condictive material for the casing...a friend's 12" 1.33GHz PowreBook is incredibly hot above the keyboard after extended use, to the point that i imagine it could possibly become a safety issue before it's an issue of component death (since the G4 can withstand 85 degrees C, which is nearly 200 degress F, enough to burn you pretty well if you're unawares)
 
I have one of those asus laptops made out of carbon fiber that you mentioned. It gets really really really hot. I'm not sure what that MBP's cpu temperature get up to, but this thing with a 2 ghz centrino idles at 65 C and peaks at about 85 C. The case still gets pretty hot especially in the few places where metal is exposed, and I'm stuck with the fan running constantly. Carbon fiber is good for somethings, but I still prefer metal for computers.

I've been patiently waiting for that xp challenge to be won so that I can dump the asus on ebay and get the computer I've wanted all along.
 
my take

if magnesim or plastic (nonconductors) are used for the body/frame, there have to be heatsinks to manage the chips heat production etc thus making the computer bigger and bulkyer. There also need to be extra fans to move air around and get it out of the body...
 
nutmac said:
If someone say one negative thing (if at that) about Apple, someone almost always reply "buy a Dell then." How old are you?
Click to expand...

:rolleyes: He said that because the original poster named these 3 brands as having a better choice of enclosure material.

He's old enough to read then, it seems.

AppleMatt
 
Just for the record, I didn't say HP's or Dell's or Asus' solution is better. I just listed what's on the market.

I am glad that this is turning into a technical thread dealing with interesting issues and not another "Go buy a Dell" thread. I don't have a laptop, all I know is from what I read in order to choose my new laptop.Currently, the MBP is the only laptop I encountered while researching to have such a hot casing problem. Doesn't seem like the E1705 from Dell, as an example, is having such an issue (with its power hungry geforce 7800 gpu), at least not from reading their forums, so I was wondering.

panoz7, your reply was very interesting.

stevep, Liquidmetal does sound promising. I can envision the "perfect" laptop that hopefully would be avaliable in a year or two:

* 64-bit Merom dual-core cpu, with lower power consumtion
* 65-nanometer GPU's, with lower power consumption
* OLED displays, reducing power consumtion of the lcd to a third (!)
* NAND chip based hard drives, allowing for 0 moving parts in a laptop and thus excellent power consumtion. Samsung just released such a laptop this week with a 32GB flash drive (Let's start with all the "Go buy a Samsung" replies LOL :) ) Here's a link: http://www.engadget.com/2006/03/10/samsung-shows-off-flash-laptop-drive-at-cebit/
It's still VERY expensive but it'll get cheaper.
* Liquidmetal casings

Oded S.
 
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