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June 2007

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Subject:
From:
Bev Christian <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Bev Christian <[log in to unmask]>
Date:
Mon, 18 Jun 2007 17:29:43 -0400
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:0  HIM

There are many fishbones like that, but Joe wants stats. There are the
usual pie charts that show that printing is the biggie for SMT
manufacturing, but I think, Joe, you want the bigger picture, right? I
don't think people are going to tell you that.  I won't.
Bev (father of 3 and no sex change operation - before or after!)
Christian
RIM

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Tremmel
Sent: Monday, June 18, 2007 5:24 PM
To: [log in to unmask]
Subject: Re: [TN] Failure statistics breakdown data?

Hello,

I remember about 2 years ago someone had a fishbone chart of what you
are
looking for and I think Bev Christain posted a link to it.  Have you
tried
contacting her off-line?

David

-----Mensaje original-----
De: TechNet [mailto:[log in to unmask]] En nombre de Joe Fjelstad
Enviado el: Monday, June 18, 2007 4:07 PM
Para: [log in to unmask]
Asunto: Re: [TN] Failure statistics breakdown data?

 
Thanks for your comments, Guy 
 
I received a few responses off line and it sounds like there exists no  
commonly collected and shared data base and that it is every company for
itself on 
this matter. 
 
As one colleague responded, "the question is an 800 pound gorilla in
the 
room" that is being ignored (perhaps in the hopes that it is a mirage?)
I  
suspect that no one wants to admit that their products are anything
short of

perfect. Who would? 
 
Your opening clarification question was a good one but I was thinking
only  
of initial turn on as I figured that was the easiest to collect and
store. 
 
BTW, I think that the IPod may have been a bit of planned  obsolesce. I
have

a major brand name electric shaver with simple rechargeable  AA
batteries
that 
recently found were welded in place. They  obviously (or at least
apparently) 
intended for it to be either  pitched or returned for the repairs at a 
handsome margin. Certainly can't  trust the consumer to change AAs. 
 
Joe      
 
 
In a message dated 6/18/2007 10:28:11 AM Pacific Daylight Time,  
[log in to unmask] writes:

Are you  talking field return or OEM in factory initial turn on. 

If you are  talking in-factory initial turn-on, typical device, solder
Defects number  1. Mostly opens because shorts are easy to detect with
inspection and ICT.  Though in my experience there special events on the
factory floor that can  change all that. 

If you are talking field returns, we have another  story. And must
include,
electronic design problems, mechanical design  problems and customer
abuse
or
misuse. 

I kept this kind of data at  an Organ Company for years. The data set
ran
from 1986 to 2000. We stored  the information on a VAX 8300. I left in
May
of
2000. I doubt they  continued to collect and analyze the data as that
machine
was expensive to  maintain and in a DataTrieve database, not easy to
port
over to  Windows.  

I can tell you this. During that time there were  periods when field
failures
were primarily design related, others when  failures were primarily
board
fab. related, periods when failures were  primarily component related
(sometimes semi-conductor other times passives)  and other periods where
failures were primarily related to manufacturing  problems. All of these
would be embarrassing for some interested party  because they were
attributable to some special cause of failure and we were  able to
identify
that special cause. 

There were very few periods in  which the population of defects would
not
have been influenced by one of  these assignable causes. So, even this
huge
data set would not tell you  want the most common "common cause" defect
would
be. My gut tells me it  would be customer misuse followed by, in the
case of
Allen Organ,  electrical or mechanical design problem. 

Other companies might have  more design problems than misuse problems.
BTW
these merge. You can have a  design problem that customers attempt to
fix,
which turns into a misuse  problem . . . . Ever tried to change a
battery in
an iPod? Is an  unsuccessful attempt a design problem or customer
misuse?  



-----Original Message-----
From: TechNet  [mailto:[log in to unmask]] On Behalf Of Joe Fjelstad
Sent: Monday, June 18,  2007 10:59 AM
To: [log in to unmask]
Subject: [TN] Failure statistics  breakdown data?

Good (time of day here) colleagues,

Does anyone  know of a statistical base that identifies assembly
failures
and traces  them to causes with some sort of breakdown? 

That is failures traced to  assembly only (e.g., opens, shorts,
insufficient
cleaning, etc.),  failures related to PCB manufacturing only (e.g.,  PTH
failure, opens,  shorts, CAF, etc.) and failures traced to the
components
themselves  of any cause (ESD, overheating, thermal cycling failure,
etc.).


I realize that this may be a sensitive topic for some folks and  am
thus
open to taking any such data off line. 

However any  perspective based on experience and "guessimates" from the
general audience  is encouraged and most welcomed to see if there is any
kind
of consensus of  experience and how close it matches with the the
industry's
general   perceptions. 

Rough (in the same city at the ball park) estimates are  OK.

Thanks in advance for any form of light that can be shed  while  I
fumble
around in the dark feeling for the "main  lightswitch".  ;-) 

Best to all,
Joe  









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