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Problem soldering to brass pin with Tin plating on Nickel flash

2003

We have SMT product with pins that are Brass with 100% Tin Plating over Nickel flash (Tin plating is a matte finish). Recently we are having problems with solderability to these pins and we are trying to figure out possible causes? We have a similar product that has pins with 90/10 plating over copper flash and we are not having these problems.

One more question, is there any place that we can send these pins to be analyzed to determine the actual plating thicknesses? We need some evaluation assistance, preferably in the MN area.

Thanks!

Brian Stuedemann
Quality Assurance - Marshall, Minnesota, USA

All kinds of questions go with this. Did you change suppliers of the plate? How long has it set on the shelf? What kind of packaging (absolutely identical or just close)?Does you plate use any brightener at all in the process? Did the plater use stearic acid [on eBay or Amazon] protection in the past and recently quit? Looking very closely, what change has come to pass anywhere in the system since a few weeks before the problem started. What is the solderability problem-exactly. What type of soldering is this. Possibly a new drum of flux?

James Watts
- Navarre, Florida
2003

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2003

The plating process is as follows: 1. check diameter 2.solvent clean oil(30-70g/l, temperature 50-70C, 5-30 minutes 3.water wash 4.a neutralizer(50-100g/l, 1-3 minutes 5.water wash 6.acid(400-600 cc/l, 1-3 minutes) 7.water wash 8.chemical nickel Ni + -2 30-40g/l, PH 4.6-5.0, Temperature 85-92 degree C) 9.water wash 10.Chromium acid(3-10g/l, 30-40 degree C, time:10-30 seconds) 11.water wash (pure water) two times 12. Drying 13.test 14.go to tin plating(Sn) 15.drying

Does anyone see any problems with this?

Brian Stuedemann
- Marshall, Minnesota, USA