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Subject:
From:
Yuan-chia Joyce Koo <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Yuan-chia Joyce Koo <[log in to unmask]>
Date:
Thu, 26 May 2016 11:36:50 -0400
Content-Type:
text/plain
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text/plain (75 lines)
good old days:
major change, any material change (including chip encapsulation, SMT  
adhesive  if it is high speed cct or high temp),  form fit function,  
MFG location change (medium - if set of tooling are equivalent and  
better, but just location change - electrical voltage of the tooling  
are different for example), any change of design rules - for example:  
on chip redundancy, vs. system redundancy using comparitor, critical  
components change - micro-processor for example, laser is another,  
etc. (optical always consider critical, or you risk in multiple way,  
wavelength, drifting, scattering, reflection, etc.

Minor change, new tooling with same platform, but more throughput,   
new location, but same tooling (do a x-y plot, one location vs the  
other, it should come out with some  correlation, in terms of yield,  
quality, etc.).  down grade environmental requirement (do not use at  
design extreme),  material from different MFG facility, but same  
vendor (you still need qual a bit - electrolytic cap from some neck  
of the woods use city water...  even under same label...  I was being  
picky to get one of my components from a specific site by paying a  
bit more... just don't want deal with un-certainty.  components bin  
change but still met the requirement (spec tolerance).  etc.  (not  
much, the list much shorter than  Major... the design don't want to  
take risk in legal sense... if design call the shot ).
my 2 cents. (oh, my dear good old days... you finish and sign off on  
the dotted line, say good bye and matching to next project without  
scare for something come back to bit you... until scheduled review -  
usually 5 years for upgrade possible platform... I guess currently  
that kind of schedule are hard to come by).
         jk

On May 26, 2016, at 10:59 AM, Douglas Pauls wrote:

> Good morning all,
>
> One of the IPC groups that I am leading is presently wrestling with  
> the
> issue of minor vs. major change.  Generally along the lines that if  
> you
> have a baselined or qualified manufacturing process, how much can that
> process change before it needs to be re-baselined or re-qualified?
> Sometimes this is referred to as Level 1 vs. Level 2 change.
>
> So far, every quality documentation system that I have looked at, like
> AS9100, ISO9000, etc., gets really fuzzy and uses vague terms when you
> approach this issue.  Most of these documentation systems have change
> better defined for products, but get extremely fuzzy and extremely  
> vague
> about manufacturing processes.
>
> This forum has a lot of very smart, very experienced people. How  
> would you
> differentiate a minor change, which would not impact form fit or  
> function,
> from a major change, which "could/would" impact form fit or function?
>
> And I want all you lurkers to come out of the woodwork on this one.
>
> Doug Pauls
> Principal Materials and Process Engineer
> Rockwell Collins
>
>
> ______________________________________________________________________
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