In a message dated 01/17/2000 4:08:03 AM US Eastern Standard Time,
[log in to unmask] writes:

> Hi, TechNetters!

Good morning Gaby.

>  How do you correlate SIR tests on coupons with real assemblies?

The short answer is "You Don't".  There is no presently accepted path from
SIR data to acceptable performance on actual hardware.  The approach I
recommend is doing ion chromatography with SIR to establish what residue
levels correlate with good SIR, then see how your hardware cleanliness stacks
up against that established baseline.

>  Do many of you perform these tests on a regular basis?

I know that several labs in the US do SIR testing.  I don't know how many of
them try to do SIR testing on actual PCB samples.  Contact me off line if you
want to discuss this testing further.

>  Thinking about buying a SIR tester.....?????

You have essentially four choices:  the SIRometer from Alpha Metals;  the
AutoSIR from Concoat/Multicore; one from ASR Instruments; and a
build-your-own system from vendors such as Keithley or Hewlett Packard.  I
have a Keithley system and an AutoSIR in house.  I know that Jim Maguire of
Boeing and Dave Hillman of Rockwell have an ASR instrument.  Figure to spend
at least $30,000 for a system.

>  And more: Do you check solder paste height? How often?
>  Thinking about buying a height tester too...???

Out of my experience base.  Sorry.

Doug Pauls
Technical Director
CSL

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