(speaking as an OEM) caveat emptor applies.
In my experience, talking about getting "full value added" refunded by a
fab usually means you're negotiating the divorce settlement.
The OEM is free to do many things to verify quality of product prior adding
value to it. At the point the OEM moves forward to assembly they accept a
large share of the responsibility for value added.
OEM's have both opportunity and responsibility to do due diligence in
matters of supplier quality and product acceptance prior to use. In the
case you describe, it sounds like the OEM further complicated the detection
of plating defects by designing a conductive via fill (yuck) so there's a
bit of a blindspot by design at the traditional end_of_process pwb ET
(another reason not to use conductive fill).
What can the OEM do?
1. Supplier qual:
The pwb customer should properly qualify a supplier including a review of
their plating processes/verifications, ET procedures and ET MRB rules.
As part of a proper survey/qual effort, I hope your supplier quality did a
thorough review of their ET procedures and records? If so, I hope your
supplier wasn't qualified until they showed evidence that opens at ET were
always analyzed classified as either trace or via opens (voids). Hopefully
you didn't have supplier get through your qual that just reported all opens
in one "bucket" without discriminating between voids and trace opens? In
truth most shops don't do this -- so most shops don't get qual'd by us. ;-)
Hopefully your supplier was qualified based on evidence that they track
overall void rates and have some idea about rate of voids on a given day
(not to mention by techology)?
Most fabs are fixated on internal yields at AOI and ET without much thought
to FMEA risks to the end user. Your job as a customer is to insist they do
otherwise or find a supplier who does see the world through a FMEA mindset
not just a "what's my biggest fab scrap today" mindset.
Most OEM's don't insist on any of this. As a result most fabs and OEMs are
flying blind vis a vis voids until the problem gets huge.
Bottom line, OEM's have an opportunity and responsibility in qual'ing
suppliers and accepting product.
If an OEM choses to place an order with a fab that doesn't have a well
documented void identification and containment plan then caveat emptor.
2. Product Acceptance/Supplier Certification:
OEM has the opportunity to test and inspect and sacrifice to science pwbs
prior to assembly.
OEM also has opportunity to certify the supplier by establishing specify
tests and inspections for the supplier to perform prior to shipment (e.g.
adequate ET and void failure analysis/containment), following up with in
process audits and source inspection
On the other hand it the supplier has been malicious, dishonest or
seriously dropped the ball on a previously implemented corrective action or
test plan -- game on.
sorry, stream of consciousness, typing fast w/out much proofreading but my
quick $.02,
dw
At 11:55 AM 11/29/2006, stephengregory5849 wrote:
>Hi Chuck!
>
>I understand that fab houses shouldn't cover costs when an assembler trashes
>a board through their assembly processes, but what about when a fab house
>gives you crap to begin with? I've posted (with pictures) many times about
>fabs that we got that were expected to be good, but as we started assemble
>the boards or after we had them assembled, we found that the fab was trash.
>
>The one instance that sticks out in my mind was when we were building boards
>for a major defense company that were assemblies that went into an AWACS
>aircraft. We had built about 400 assemblies and shipped them when we
>discovered that there were vias in the fab that had little or no copper
>plated inside the barrels! It was only a fluke that we discovered this as I
>had a crosssection done on a bare fab for no particular reason. The fabs
>passed bare board testing and post assembly testing because the vias were
>filled with silver conductive epoxy. The boards were supposed to be built
>according to -6012. When we informed the fab vendor of what we discovered,
>we asked to see the cross-sections that they had performed on the previous
>lots of fabs that they built for us...they couldn't produce any
>cross-sections for us.
>
>To make a long story short, we recalled everything that we had built and
>started over from scratch with a different fab vendor...and ate the costs
>for everything that we had built. The fab vendor wasn't willing to cover any
>of our manufacturing costs, but was willing to give us new boards...yeah
>right. Like we would really want anymore fabs from them. It was decided that
>after you figured in lawyers fees and everything that it would take to prove
>our case in court, it would be a wash. So we decided to cut our losses and
>start over again.
>
>Our customer wasn't too happy but they were grateful that we found the
>problem when we did before any of the assemblies made their way into an
>aircraft...
>
>This is just one of many cases that I have experienced like this from
>various fab houses...
>
>All I can say is buyer beware.
>
>-Steve Gregory-
>
>----- Original Message -----
>From: "Chuck Brummer" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Wednesday, November 29, 2006 12:29 PM
>Subject: Re: [TN] FW: Delamination pics (IS410)
>
>
>>Steve,
>>
>>The reason the fabs can't cover the cost of your parts and labor is
>>because everyone wants multilayer boards at pennies per square inch. No
>>possibility of covering warrantee costs as you add 10x the board cost when
>>you blister the boards assembling them. If one bad job eats the profit
>>from 100 the fabs will be out of business in a week. Maybe the designers
>>should spec materials that can handle the heat instead of FR-4 with the
>>cheapest oxide.
>>
>>just my opinion.
>>
>>Chuck Brummer
>>3M Manufacturing Engineer
>>8357 Canoga Ave.
>>Canoga Park, CA 91304-2605
>>(818) 734-4930
>>
>>
>>
>>
>>stephen gregory <[log in to unmask]>
>>Sent by: TechNet <[log in to unmask]>
>>11/29/2006 09:11 AM
>>Please respond to
>>TechNet E-Mail Forum <[log in to unmask]>; Please respond to
>>stephen gregory <[log in to unmask]>
>>
>>
>>To
>>[log in to unmask]
>>cc
>>
>>Subject
>>Re: [TN] FW: Delamination pics (IS410)
>>
>>
>>
>>
>>
>>
>>Good Morning to you Gloria!
>>
>> I've got your Word doc. file with the pictures posted at:
>>
>> http://www.stevezeva.homestead.com/files/dELAM.doc
>>
>> Looking at the pictures, I'm assuming that each page shows images from a
>>different area. It's worth noting that the delamination appears to be at
>>the same layer, or am I wrong about that?
>>
>> What is your fab vendor saying about this problem?
>>
>> What I'm about to say isn't trying to slam all board houses, but in all
>>the years that I've been working in this business, I've found that almost
>>never will a board house fairly compensate a company after they've found a
>>problem with a fab after it's been built. Most of the time they've said
>>they will give us new boards, but won't compensate us for the labor and
>>materials in the assembly, and I think that sucks.
>>
>> Looking at all the pictures you've sent us, I definitely think it's a
>>fab problem, not any of your assembly processes, and I would be leery of
>>shipping any product that is using these fabs.
>>
>> But that's just my opinion...
>>
>> -Steve Gregory-
>>
>>Gloria Brown <[log in to unmask]> wrote:
>> Good Morning Steve,
>>
>> We had a micro section completed on the delaminating area of the boards
>>here that we are finding that same issue with. Thought I would share them
>>as well. I know that I cannot send them to the forum so if you can post
>>them like you did the others and share them also please do.
>>
>> Thanks
>>
>> Gloria Brown
>> phone 906-932-5970 ext. 26
>> fax 906-932-9822
>> [log in to unmask]
>>
>>
>>
>>
>>
>>
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