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Subject:
From:
Inge Hernefjord <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Inge Hernefjord <[log in to unmask]>
Date:
Thu, 7 Jul 2016 17:08:31 +0200
Content-Type:
text/plain
Parts/Attachments:
text/plain (128 lines)
Correction line 5  shall be :  aquisition, they can NOT accept such ...
sorry


On 7 July 2016 at 17:05, Inge Hernefjord <[log in to unmask]> wrote:

> Well, I'm not much of the adviser I once was, so the question is if you
> should read this.
>
> -  You've already answered yourself when you ask for the level of a minor
> deviation,which doesn't have a dentrimental effect on the process, and
> ditto about a major deviation. Practical experience will give the level
> individually for each process.
>
> - In fact, the two parameters 'minor' and 'major' are not of interest in
> programming point of  view, because the machines that sample and do the
> data aquisition, they can accept such arguments as 'minor' and 'major' ,
> because they want mathematic useful levels, e.g. so and so many
> milliamperes or nn % or other expressions..So, I would skip the whole
> question and give the processing computer values that counts.
>
> - There is a area that has the most advanced processing of all, namely the
> semiconductor processing. The sharpest brains arfe involved and there you
> have the answers on practically everything you want to know..One reference
> that I used to read is Dimitri Kececioglu and Feng-Bin Sun's wwork '
> QUANTIFICATION and OPTIMIZATION OF BURN-iN TESTING. isbn 0-43-324211-0.
> Editid and printed by Prentice Hall, Upper Saddle River, NJ 07458.
> Examples on content
>
> Chaper 4: Obsevations and the physical insight of the failure process
> Chapter 5: Math  Models Describing the Failure Process during Burn-In and
> the Parametres Estimation.
>
> -  What more to say is that your question is more or less difficult to
> quantify, because of the complexity of  the actual process.  If yoy ask for
> a simple process, let's say the manufacturing of a general purpose, cheap
> resistor with the tolerance of +/-  10 %, you have only one proceessto keep
> an eye upon, the laser trimming. If the you use modern trimmers, the
> outgoiing tolerance is probably much better for Sigma 1-3, while Sigma 6
> represents only a few + 10% or  .10 % per each one million batch. That
> means that a deviation from normal +/. 2 %  to new value l.et's say +/- 5
> % is not causing any problems.
>
> Making a car, for instance, is so complex and holds so many parameters
> (thousands) that you need aqusite data for hundreds of cars before you get
> experience of what deviations are acceptable or not. So, take into
> consideration the complexity of the process you are asking for.
>
> My 2 p +/- 0.05 p
>
>  /Inge
>
> PS. Think your younger and  fresher (?) mate Dave got a lot to say.
>
>
>
> On 30 May 2016 at 01:54, Yuan-chia Joyce Koo <[log in to unmask]> wrote:
>
>> hopefully, it is not voting system.  otherwise, you get vote out to the
>> lowest std.  (one system designer, with many part vendor, supplier,
>> marketing guys, bean  counters, etc. the program mgr will get over powered
>> sometimes... horrible).
>>         jk
>>
>> On May 29, 2016, at 2:19 PM, Richard Kraszewski wrote:
>>
>> I would suggest  the use of a pFMEA or dFMEA  to assist in making that
>>> decision.
>>> Need to have all stakeholders involved in that exercise.
>>> (yes I know this can be pain)
>>>
>>> Rich  Kraszewski
>>> (920) 969-6075
>>>
>>>
>>> -----Original Message-----
>>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
>>> Sent: Thursday, May 26, 2016 10:00 AM
>>> To: [log in to unmask]
>>> Subject: [TN] How much change is change?
>>>
>>> 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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>>
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