Doug, 4.2 in IPC-6012 implicitly calls for IPC coupons by its reference to Table 4-3.  The fabricator would want to locate coupons to optimize yield from the panels, so you are correct in not providing coupons. IPC-2221 defines permitted locations.

Here at Compunetics, we keep all microsections for a minimum of 3 years, except in rare cases when a customer requires that they be sent with boards.  For those case, we note in our files and storage areas that the customer has the microsections.  If a customer wants only one microsection, we just make an extra mount in addition to the 6012 complement.  I have told people that these microsections are the documents, among others, containing evidence that the boards - the ones we ship, at least - met requirements.

Louis Hart

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Doug DeVries
Sent: Wednesday, April 30, 2014 12:14 PM
To: [log in to unmask]
Subject: [TN] IPC 6012 test coupon question

Hi all - This is my first TechNet post.  Hope I'm doing it correctly...

We commonly design and order rigid PCBs which contain in the fabrication notes the wording "Must meet or exceed the requirements of IPC-6012 - Class 2".  We do not normally add test coupons, such as the IPC A/B coupons used for microsections, into the files that we deliver to the PCB fabricator.  I've always assumed that it was their job to add the necessary coupons to comply with IPC-6012 quality requirements when fabricating the boards.

Recently I found myself in a small debate with a large, reputable PCB fabricator when my customer asked me to "show me the IPC quality data" on a recent job.  I had ASSUMED the PCB supplier was gathering said data from the IPC test coupons that I ASSUMED the PCB supplier was adding to the production panels.   I thought it was REQURED by IPC 6012 that the coupons be used on the panels.  I was taken aback when the fabricator replied to my request for the data saying that they "don't use the IPC coupons" but rather use their own "special coupons" that are much more sophisticated that the IPC coupons, allow for better process control and blah, blah, blah.   They also said they couldn't supply me with microsections from any of those coupons because they were all used / destroyed / discarded during or soon after processing...  I had some egg on my face when I went back to the customer.   Turned out there wasn't any actual problem the boards, but I feel like I got a wake-up call of sorts.

My question is:  What can I do to avoid getting into this situation in the future.  Do I need to put some or all of the various test coupons into my data that I supply to the fabricator?  Would adding a requirement such as "Micro-section and First Article Inspection (FAI) report shall accompany every lot."

As I mentioned, this PCB supplier is very large and reputable.  I have no real reason to doubt that their methods are according to Hoyle, if not IPC.  There was no actual quality problem, just a scare for me.

Doug


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