

Message-ID: <380F4F3B.4BFFBA44@buffnet.net>
Date: Thu, 21 Oct 1999 13:36:59 -0400
From: Roger Morella <rjm@buffnet.net>
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To: 68HC11@oakhill-csic.sps.mot.com
Subject: Re: [OT] Survey... What is an acceptable failure rate?
References: <199910211628.LAA09586@ftpbox.mot.com>
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Sean,

I'm not really looking for sympathy... just opinions.  I realize now that I shou
ld
have stated my questions more definitively.

Here's whats going on. We have a customer who equates a component failure with n
eglect
on our part.  His reasoning is that if it failed it must be because we designed
inferior components into the product.  From my understanding, everything has a r
eal
Mean Time Between(Before?) Failure rating.  The key word being "Mean".  It may h
ave a
MTBF of 10 years, but it doesn't indicate where in that 10 year span it's going
to
fail.  Some units will fail right out of the box.  While you can strive to reduc
e that
probabilty, you can not absolutely guarentee that a unit will not fail or when i
t will
fail.  You can only offer a warrenty that covers the cost of the repair for a
reasonable period of time. I guess the question is, what is reasonable? What I w
as
looking for was some sort of consensus as to what reasonable is.  Our customer c
laims
that 1% failure rate over 3 years is the industry standard. (from what I have se
en and
heard so far there is no industry standard) If I use his assumption, that means
that
the MTBF is 300 years.  Is this reasonable? If it's not, how do I convince my
customer?  If it is, how do I convince my boss?


Sean Cleary wrote:

>  Message sent by Sean Cleary <SeanC@irvingrp.com>
>  to the 68hc11 Mailing List.
>
> Roger,
>         Some of the reason why you are not getting much sympathy is that stand
ards
> have tightened. Quality is very important, and international competition has
> made this clear. One part of Quality is how long the piece goes without
> annoying the purchaser, and this leads into your topic. Quality rates that
> were acceptable a decade ago are not tolerated now. This is true in all
> fields, with only a possible exception of the cheapest junk on the market. I
> suspect that even that has had to change in order to sell. Example: American
> cars. But other examples are all around us.
>         Sean
>
> IMHO,
> Sean Cleary
>
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