Soldering issue.

[itsmoked]

We have a pick-en-place running and am having a nasty problem with the subsequent reflow soldering.

These pictures are examples of the problem. We get no tombstones at all. The joints that solder are excellent but each board has approximately 7 of these soldering failures. They're a nightmare as one has to look at every part under high magnification to spot them. Then, after one thinks they've found and fixed them all, boards fail test and extensive troubleshooting 90% of the time shows one of these that's been missed.

Frequently we'll find the same side of the same part on multiple boards demonstrating this.

We're using ChipQuick lead solder about one screen number smaller than standard.

When we were using a "standard" temp profile. We had 32 boards out of 32 having this problem.

Running a test we changed the temp profile to exactly what ChipQuick specified. No improvement.
We added 5 seconds to the end of the profile peak. It didn't improve.

We added 5 more seconds (10 total) and it seemed to improve by about 40% less errors.


Suggestions?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[hacksaw]

This issue started for me in the nineties.

It is not the quality of the solder or the flux, the old stuff is still available if you look for it.

It is more an issue of surface metallurgy. Even copper wires (modern) seem to be afflicted with impurities and nearly impossible to achieve good solder joints.

Welcome to the modern age...

 

[IRstuff]

Current copper price is ~5x what it was in 2000 and was as high as 9x. This easily leads to same issue with expensive drugs; they get cut with filler. Additionally, at its peak price, people were stealing copper for recycling; the recycled material likewise contains impurities.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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