Agreed. This is particularly true, I think, in analogue circuitry. For
example, (based on occurrences here) a mistaken capacitor value could
dramatically alter the loop gain of an oscillator, possibly leading to
intermittent startup problems with the circuit that might not always be
detected in test and yet still decrease the reliability of the product.
However, it is likely that passives in certain portions of a circuit are
more critical than in others. Perhaps Quality could work with the designers
to determine different criteria for different products or portions of
products. Perhaps I should coin a term: continuous concurrent engineering
:-)
yves
Yves Dupuis
Process Engineering
Leitch Technology
> -----Original Message-----
> From: Dave Girard [SMTP:[log in to unmask]]
> Sent: Monday, May 14, 2001 1:03 PM
> To: [log in to unmask]
> Subject: Re: [TN] Inspection
>
> Kevin, I agree with you and your 1st inspector. Test is by far no
> guarantee that wrong components will be found. Even a full blown
> operational test at temperature extremes will not weed-out "all" wrong
> components. I remember an experiment I did about 20 years ago where I
> tested a group of PWAs before they were inspected. Of the ones that
> passed test, about 20% of them had wrong or reversed components that I
> later found.
>
> Dave Girard, CQE, CQA, NCE
> Group Leader, Quality Engineering
> CAE USA
>
> "TechNet E-Mail Forum." <[log in to unmask]>,
> "PERALTA, Kevin (BREA)" <[log in to unmask]> wrote:
> >
> > We have a situation at our facility in which I feel two inspectors are
> > correct from two perspectives. I would like to ask members to submit
> > situations and, or fixes to the following:
> >
> > IPC-A-610 does not mention acceptance criteria for component location &
> > identification for components that are too small to identify (e.g.;
> SMT).
> > One inspector does not want to accept something by faith, and there's no
> > callout for the ID of a component on an electronic assembly that is too
> > small to identify on our blueprint. He would like to reject them, and
> let
> > MRB disposition the rejection, which I feel is correct.
> >
> > Our other inspector will still accept the assembly on the basis that
> testing
> > will confirm if the component is the correct or incorrect one.
> >
> > From a production supervisor's perspective, the latter is preferred.
> But,
> > from a Quality perspective, the former process should be followed. There
> is
> > no mapped out process for this situation. I actually had an engineer
> tell
> > one of our inspectors, "that if it was the wrong component, it would not
> fit
> > in it's place on the assembly" (I think we shipped him off to Alaska)!
> >
> > I'd appreciate any response sent to me, and would invite any questions
> > concerning such situations. Thank you!
> >
> >
> > Kevin L. Peralta
> > Class "A" Instructor
> > Senior Quality Systems Analyst
> > TRW Aeronautical/Lucas Aerospace
> >
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