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From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Disk drive handling in assembly
References: <3D9CF7A9.BF4BB1C0@webaccess.net> <email@example.com> <3D9D8B86.C935D6CB@webaccess.net> <firstname.lastname@example.org>
Date: Fri, 04 Oct 2002 14:16:25 GMT
NNTP-Posting-Date: Fri, 04 Oct 2002 07:16:25 PDT
Nico Coesel wrote:
> Chuck Simmons wrote:
> >Nico Coesel wrote:
> >> Chuck Simmons wrote:
> >> >I have a few questions about how hard drives are handled in assembly
> >> >situations when hundreds or thousands of drives might be handled in a
> >> >day. The motive for this question derives from a question about high
> >> >failure rate experienced by a particular company. I have already given
> >> >my views on the problem to the engineering VP of the company and I am
> >> >arraging a consultant to check my conjectures and look for other
> >> >problems. But my questions concern how other companies handle hard
> >> >drives. My questions are the following.
> >> I've had a discussion with several other people about similar
> >> problems. It seems that some batches are transported more carefully
> >> than others. This causes some companies to receive a batch with a high
> >> failure rate while other companies have near no zero problems with a
> >> particular type of disk.
> >Handling damage in small drives makes transportation damage a sort of
> >background noise. In the 3.5 inch drives, I know of no documented case
> >of systematic shipping damage while installation handling damage has
> >been documented many times. I was asked to look at this from the drive
> >maker's point of view since that is where I come from. Transportation
> >damage is very low probability from that point of view. Handling damage
> >is definitely the front runner.
> From what I've seen in several computershops they don't have soft
> benches, ESD precautions, etc. I have no idea how Dell, HP, etc
> assemble their PC's. If a hard drive is so sensitive to mechanical
> shocks, why isn't there a big-fat-warning on the drives?
I don't know. When I was in the industry, I was alarmed that
distribution channel drives had only mild handling warnings. Some of us
occasionally brought up the question in meetings with marketing. They
seemed to be willing to take risks in the distribution channel.
> Just a question from curiosity: how can you be sure that most damage
> is handling damage during assembly? I mean, I'm wondering how you
> could see wether a drive is damaged during transport or during
This all came from in house testing and on site troubleshooting of OEM
process in installing drives. Shipping packages are designed to take a
drop from a moderate height. Once out of the factory shipping package, a
drive is completely vulnerable. Measurements show that gently setting a
drive down on a hard surface can exceed non-operating shock
specification. Setting a drive down gently on a wooden desk produces an
acceleration of 100G or more. If such a shock causes a head slap, the
drive has a higher likelyhood of failure. All drive makers have some
direct measure of this. Moreover, the drive design community is small.
There aren't really that many engineers in the area so there are few
secrets. I know designers at all the US makers and there is hardly any
other game in town (I probably know some guys at Fujitsu but I can't
keep track very well).
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons email@example.com
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