Guy,



A couple of points about coupon selection:



1. The standard coupons are useful for collecting data that you can compare to industry accepted values. You are essentially demonstrating the capability of your cleaning process. But you also want the coupon to be representative of your hardware, and that's where newer coupons containing those parts that Doug mentioned can be a good choice. (Keeping in mind that some old parts are still challenging as well!)



2. When you look for a coupon that is representative of your hardware, the obvious thing to look at are the components included. But you'll want to keep some finer details in mind, such as solder mask configuration. Does the coupon have the same solder mask thickness or pattern as your hardware? On low standoff parts, this can have a large impact.



Ben 



-----Original Message-----

From: TechNet <[log in to unmask]> On Behalf Of Douglas Pauls

Sent: Friday, December 20, 2019 9:36 AM

To: [log in to unmask]

Subject: EXTERNAL: Re: [TN] [External] [TN] SIR test coupons, Magnalytix



Good morning Guy,

Joe Russeau gave a pretty good summary on the IPC-B-52 test assembly and

9202 protocols.  The 9202 is wrapping up some of the Rev A work (I hope) but is still focused on the B-52 assembly.  It is a good test vehicle and continues to provide valuable insights into manufacturing processes. The primary criticism is that it was designed in the early 2000s with components common to that time frame.  It does not contain some of the more challenging components like QFNs or mammoth BGAs.  While the B52 does have areas where those components can be designed in, and some people have, but I see a whole new vista of SIR tools coming to the market.



I have worked with Mark McMeen and Mike Bixenman of Magnalytics for about the last 2 years on developing their SIR test system.  I am excited about the system and plan on getting one myself once the development phase is done (which is pretty much now).  We are presenting a paper at Apex on some of  our work to correlate their test card with the B-52.  The Magnalytix card has QFNs, BGA and the B52 QFP80 patterns.  Mark has also developed a series of test cards to look at other aspects of residues and manufacturing processes.  I haven't had this much fun in years.





*Douglas Pauls *| Principal Materials and Process Engr | Advanced Operations Engineering



*COLLINS AEROSPACE*



400 Collins Road NE, MS 108-101, Cedar Rapids, IA  52498  USA



*Tel:* +1 319 295 2109 | *Mobile: *+1 319 431 3773



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On Thu, Dec 19, 2019 at 2:18 PM Guy Ramsey <[log in to unmask]> wrote:



> We have been exploring the J-STD-001G amendment.

> We think we have a "qualified" process because:

> 1. We have monitored our process for several years and established an 

> action threshold at a level that is much lower than the old IPC limit.

> Because with know the "normal" ROSE test result from or Ionograph.

> 2. We have never seen evidence of corrosion on assemblies returned 

> from the field. And have no reports of corrosion from customers.

>

> But, we have not done any SIR testing in years. The mix of parts and 

> part densities have changed dramatically. We have no reason to trust 

> the old SIR test results.

> We would like to gather objective evidence that our cleaning process 

> is compliant.

>

> Any experience out there with the Magnalytix system?

> Any advice about test coupon selection?

> Anyone?

>