Sn63Pb37 does oxidize over time, and as such can pose a problem for ICT and flying probe contact pressures.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Thursday, May 10, 2012 11:50 AM
To: [log in to unmask]
Subject: Re: [TN] IPC-5703 Question 1
Doug,
The idea that HASL was/is associated with residues on test probes makes no sense to me. Flux and board cleaning, now that is an issue.
I have a Z-1820 ICT machine and I use only HASL PCBs. The only residue I have ever heard of being a problem on test points is flux residue. And, without a doubt flux can be an issue.
Flux is not a problem on most test points as the shape of the probe is often one with sharp points and steep sides. They go through flux fine. When you probe gold fingers you might have rounded end probes and any residues there are a problem. But you should not have residues on gold fingers in the first place.
I tend to be in a minority as I prefer HASL to other finishes. Reflow is fantastic, flatness is not an issue as stencil printed paste goes over the raw pads. Nickel is just not as easy to solder to as solder coated copper.
No one ever got "Black Pad" on HASL.
Thanks,
Bob Kondner
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jerry Dengler
Sent: Thursday, May 10, 2012 12:30 PM
To: [log in to unmask]
Subject: Re: [TN] IPC-5703 Question 1
Hi Doug,
I work for an EMS company so I do not have any experience with this but offer the following thought.
HASL is still used so if it was a cause before it is still a potential cause in my opinion.
Regards,
Jerry Dengler
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: Thursday, May 10, 2012 12:18 PM
To: [log in to unmask]
Subject: [TN] IPC-5703 Question 1
Good morning all,
I am working on a draft of IPC-5703, titled " Cleanliness for Fabricators", a kind of Cleanliness 101 for board fab houses. It should be ready for wider review in a month or so, but you can see drafts of it here.
http://www.ipc.org/CommitteeDetail.aspx?Committee=5-32C
So you will see several questions from me.
Question 1: In the board fabrication process (not the OEM/EMS assembly process), have any of you ever seen residue accumulation on in-circuit test pins or flying probe test pins which interfere with in-circuit test continuity? Our board shop says it does not happen today. It was a more common occurrence 10 years ago when HASL was more prevalent, but I don't believe it happens today.
Agree or not, and why.
Thanks.
Doug Pauls
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