-- The Home Page of the Finishing Industry
23+ years of serious education, promoting Aloha,
& the most fun you can have in metal finishing smiley
    no popups, no spam
on this site
current topics
topic 8899

Bright vs. matte for reflow


We have experienced solderability problems with a brass pin with copper flash, 100uin min nickel plate, 200 µinmin 60/40 tin/lead plate (bright). The pin is subjected to a surface mount reflow process prior to wave soldering. It is during wave soldering that the problem occurs. We believe the main contributor is the bright tin/lead plate subjected to reflow. We received freshly plated pins both bright and matte and subjected them to a tyupical surface mount convection reflow profile. The bright pins darkened and appeared rough and showed non-wetting when solder dipped or wave soldered. The matte pins brightened up and showed good wetting when dipped even after five reflows.

I am looking for confimation that matte tin/lead plate is more appropriate than bright for a part that is subjected to convection reflow and then must be wave soldered. Also, for improved shelf life/solderability, would it be better to receive the pins already reflowed rather than sitting on the shelf waiting for reflow in our process? And is the shelf life of 90/10 significantly different than 60/40?

Pat Bailey
- Redwood Falls, MN, USA


Pat -

You should have the parts reflowed before letting them sit on the shelf. A matte finish is typically more subject to contamination than a bright finish. If the bright parts you are using are a bright acid and not a reflow this could be causing problems because of the organic brighteners in the bath/tin lead.

John Bowers
- Everett, Massachusetts

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.