Hi Bev,
ah..don't you recall arguing about how many random variables to lump while writing 2.6.3.7? It was so painful that we gave up. Ditto for the stabilization requirement, which I see treated in Inge's link.
Bellcore sets up an isolation of one material or process (i.e. flux/prep, or inner layer cleaning prior to lamination) and leaves the rest pretty vague.
If memory serves, issue 1 requires the geometric mean > 8.0, with a minimum of 30 readings (you can dump 2 of the 32 for assignable causes).
In the Bellcore world this is 8 combs (regardless of how they are palletized), 4 measurements/comb- 1-2,2-3,3-4,4-5.
I would highly recommend using 32 the B-52 combs instead. Forget the ohms/square adjustment protocol; it is useless for today's materials at Bellcore's measurement voltage.
Can't RIM afford the $1250 to buy issue 2? :)
As you are probably aware, most of the underfill marketing material is B-24 IPC SIR only.
I believe the J-STD-004B a1 ballot result was a 36 hour grace period. There will likely be some false conformances caused by using such a simply rule, but hopefully if the graphs are expected, we'll be ok.
Chris
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Thursday, October 14, 2010 2:30 PM
To: [log in to unmask]
Subject: [TN] Interpretation of SIR Requirements
TechNetters,
In GR-78-CORE, Issue 1, 1997, SIR Test Procedure 13.1.3.2 R13-6 [808], it states (capitalization mine) "The average insulation resistance (megohms), for EACH SAMPLE GROUP, taken at 24 hours and again at 4 days, shall be greater than the minimum specified in table 13-4.
In IPC J-STD-004B, 3.4.1.4.1 Reporting SIR Test Results, the first criteria for passing the SIR test is: "All SIR measurements on all test patterns shall exceed the 100 Mohm requirements."
My questions are as follows:
1) In the Telecordia document, what constitutes a "sample group"? One comb pattern? All the comb patterns on one coupon? All the coupons being used to test one material?
2) For the IPC method does the criteria apply to the readings at the end of the test? First and last? At every measurement? The document seems vague to me.
Bev
RIM
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