hardness test

Question

Level 1

8 points

hardness test

I have a question. What is the specification for the hardness of the plastic used on the nano?

I have access to testing equipment and would be happy to do a Brinell Hardness test on my nano to determine if it is up to spec.

I work in an industry that uses testing standards to determine if a product is as advertised. ie. astm specs. ect.

I am sure there is a scratch resistance specification available for plastic. Can APPLE please publish their internal spec.s so customers can determine if theirs meets the spec.

Best regards, Mark

Posted on Sep 27, 2005 2:50 PM

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Answer 1

Top-ranking reply

Tark Bunch

Level 4

1,065 points

Sep 28, 2005 7:10 AM in response to MARK KOHLER1

I don't mean to be insulting here, but your Apple-baiting come across as a little childish. The hardness value of the nano may not be a quality control value tracked by Apple as this was never a problem until this product launch, therefore there may be no specification for it to publish.

If you are a real engineer or scientist, you would go ahead and take the initiative to test the sample you have with the most appropriate objective test.

I am scientist, not an engineer, but a quick search on Wikipedia would indicate that the tests you may wish to employ may be the Knoop test (a micro scale test able to test materials as soft as gold foil) or possibly the Shore hardness test for polymers.

I suspect that there may be a sub-lot of polycarbonate plastic on some nanos that was not cast or cured properly that may truly be more scratch-prone. I only have one black nano which I protect in an iPod sock and have no scratches to complain about.

Complaints about chrome scratching when placed in a plastic bag are just foolish. I suspect these were actually scratches in finger oils (which I have seen on my nano and were easily wiped away with a soft cloth).

If you are really interested in knowing the the hardness value, go ahead and do the test and report your results. I'm sure you have tables of hardness values for materials where you work, use these to help select the proper test conditions (we all you know you are testing plastic, not metal and shouldn't be performing the Brinell test).

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Answer 2

Sep 27, 2005 4:59 PM in response to MARK KOHLER1

Brinell Hardness test? Sure hope thats not the same Brinell test I have done in the past. 3000 kg load for 10 seconds with a 10mm hardened steel ball. Leaves a sizable impression in a piece of steel. I'm sure it would crush any of the ipods. I know there is a brinell test at 500 kg but still would do in any ipod.

sure your not thinking of some other hardness test appropriate for plastic, or perhaps there is a brinell test at a much lighter load and smaller indentor.

Rick

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Answer 3

carl wolf

Level 6

14,631 points

Sep 27, 2005 7:07 PM in response to MARK KOHLER1

You should be careful which test you use. The Brinell Hardness test is inappropriate; rather, you should do a Taber Abrasion test. I suggest that you familiarize yourself with the ASTM testing standards and procedures.

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Answer 4

MARK KOHLER1 Author

Level 1

8 points

Sep 28, 2005 7:54 AM in response to Tark Bunch

Tark,

My background is materials engineering. (VIRGINIA TECH)

I have worked for the last 23 years in the Steel industry.

I can however assure you that the plastic industry and the consumer electronics industry has purchasing specifications that are extremely detailed. For example, I was told by Dupont that one of the raw materials that I sell might require 5 or more years of testing and evaluation before they could consider allowing it's use in their product blend.

I am certain that Apple knows exactly the hardness/scratch resistance specification for the plastic used in the nano.

The problem is that I as the consumer do not have access to this information.

When I watched the roll out demonstration, and Steve Jobs pulls his nano out of his watch/change pocket of his jeans, I take him at his word that this product is designed for that purpose.

Now the question has been put, does this product scratch easily? The only objective way to resolve this is testing against the OEM specifications.

I cannot give a pass or fail evaluation without a qualifying standard from apple.

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Answer 5

Tark Bunch

Level 4

1,065 points

Sep 27, 2005 4:49 PM in response to MARK KOHLER1

I don't know if Apple would release the specs to you or broadcast them to the general public (and their competition)

On the otherhand, if you have access to the normal iPod and the nano and could do hardness testing on both devices (without breaking them!) You might be able to test Shiller's response that the nano's plastic is the same as the regular iPod (which I believe is true) but no one can argue with real unbiased data!

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Answer 6

Tark Bunch

Level 4

1,065 points

Sep 28, 2005 8:32 AM in response to MARK KOHLER1

Mark,

thanks for your clarification regarding your background. The nano surface I suspect is cast and not machined.

A machneable material should conform to a specific criteria.

I don't know if the nano face is polymerized when it is cast or if it is cast from a raw thermo-plastic. If I understand correctly, thermo plastics usually come as granular material that may not lend themselves to a hardness test (I could be wrong here).

I do know that in the manufacturing industry, you spec out what should to be a quality indicating attributes, but sometimes later when the product is in the field that there is was a previously unidentified attribute that if impacting the quality of the product and now requires defining.

The hardness of the nano display may fall into this camp.
A rude surprise to both Apple and the consumers who purchased "soft" nanos.

Fortunatly form me, my nano is pretty hard and reasonably scratch-free (but I'm not going to send it to you for hardness testing 😉

PS: Apple engineering tolerances may be part of Apple's IP and Apple may not wish to disclose these unless under a signed confidentiality agreement between Apple and its suppliers.

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Answer 7

Sep 28, 2005 12:03 PM in response to MARK KOHLER1

Mark,

"So Matt, your conclusion is that the nano should not be carried in a pocket?"

Not if you wish to keep it in "mint" condition.

Matt

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Answer 8

MARK KOHLER1 Author

Level 1

8 points

Sep 27, 2005 5:21 PM in response to MARK KOHLER1

Well, I'm glad someone is doing their homework.

Yes Brinell is a standard hardness test for metals.

However, my point remains: what will , or rather what does Apple maintain: should cause damage to the plastic?

IF you read their newest response, it says you should get a cover if your concerned with scratches.

How do I know that the plastic in the cover will not damage it? Cannot Apple with all other technology and engineering power put a #, a definable hardness, a specification on what should or should not cause this plastic to scratch?

Let's stop talking about opinion and perception and do some ASTM testing.

best regards, Mark

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Answer 9

Sep 27, 2005 5:25 PM in response to MARK KOHLER1

Doesn't Apple saying you should get a cover if you are concerned about scratching an admission that it will scratch under normal use? I would be interested to hear an official Apple answer to the question "Is the Nano expected to scratch so badly it causes screen distortion when carried on its own in a pocket?"

As far as I can tell everything points that the answer to this would be yes. In which case I can't see how the Nano is fit for purpose as a portable device.

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Answer 10

Tark Bunch

Level 4

1,065 points

Sep 27, 2005 6:02 PM in response to MARK KOHLER1

Hardness testing aside,
my nano is doing just fine in an iPod sock. I have owned many iPods, all have scratched. Then nano appears no different from my experience, but it is holding up quite nicely in the sock.
I don't know if there is a sub-lot of nanos out there with a poorly polymerized surface that is more prone to scratching, I am not seeing it with mine, but I only have had experience with one nano.

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Answer 11

MARK KOHLER1 Author

Level 1

8 points

Sep 27, 2005 7:17 PM in response to Tark Bunch

well, you see this is the point for many who bought this product based on the promotion from apple. It has been promoted as a device that can be carried in your pocket.

I do not carry things in my pocket that need to be enshrined in gummy wraps.

I do not have a cover for my cell phone. I do not have a cover for my computer keyboard(I know such things exist, but if the keyboard would not work after getting dusty, I would consider it defective) I do not have a protective film on the windshield of my car.(If it became scratched so that I could not see through it, in several days of normal use:I would consider it defective) If I cannot use this item without a cover, it should not be sold without a cover. Hence it is defective and I would like to return it. All I get when I call APPLE is "APPLE HAS NOT DETERMINED THAT THE PEODUCT IS DEFECTIVE"

THIS IS A DESIGN DEFFECT.

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Answer 12

Sep 27, 2005 7:18 PM in response to Maverick808

Philip Schiller, Apple's senior vice president of world-wide product marketing, said a "vendor quality problem" caused cracking on a small number of iPod-nano screens, affecting "less than one-tenth of 1%" of the devices Apple has shipped. Mr. Schiller said Apple's iPod-nano warranty will cover devices with cracked screens.

Apple's Mr. Schiller said the iPod-nano case and screen aren't more susceptible to scratching than previous versions of the iPod and that the company has received few complaints about the matter. On Mr. Peterson's Web site and others, iPod-nano users complain of abrasions on their screens. Jeremy Horwitz, editor in chief of the iPod enthusiast Web site iLounge, said the company has received many reports of scratched screens from the site's readers.

Mr. Horwitz, in an email message, said iPod users have complained of scratches on prior versions of the iPod, one reason that protective cases have been so popular for the devices.

The Wall Street Journal

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Answer 13

Sep 28, 2005 7:41 AM in response to MARK KOHLER1

Mark,

"I do not carry things in my pocket that need to be enshrined in gummy wraps.

Perhaps not.

But what about a shiny, new, freshly minted quarter? Carry it in your pocket for a while and it's not going to look so shiny and new any more either.

Matt

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Answer 14

Sep 28, 2005 7:46 AM in response to MARK KOHLER1

You carry a cell phone in your pocket? Does it get scratched?

Mine does.

Get a life, whiny people! Look, it's a machine, not a diamond coated piece of unobtanium. It will scratch. Worried about it, buy a case like everyone else.

Sheesh!

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Answer 15

MARK KOHLER1 Author

Level 1

8 points

Sep 28, 2005 9:18 AM in response to Dana Kincaid

Dana

You carry a cell phone in your pocket?

Sure do. Half the time it rolls around the floor of my car or in the center holder on rental cars.(my mini-van does not have a hoder so it goes on the floor beside the bucket seat so I can find it in the dark without taking my eyes off the road.)

Does it get scratched?

No, it is a clamshell design. I think this is the reason that despite being very thin, the motorola razr remains a clamshell design.

This is why I have concluded that the nano is a design defect. The plastic is very soft(how soft I am trying to determine) and yet Apple sold it as a
pocket portable device. Now they say: that's crazy, of course it will sratch, get a case!

I would like my money back.

I am told no. There is nothing defective about the product. We will not refund your money.

As a lifelong engineering salesman, I do not treat my customers this way and will not tolerate being treated this way.

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