Electronics Forum | Mon Aug 01 06:59:02 EDT 2005 | Joseph
Dear all, We observed visible micro crack at top side of solder fillet during lead free wave solder process. We did not see any visible micro crack at bottom side, and it always located at joints of transformer. Any input be much appreciated. Best
Electronics Forum | Mon Aug 01 08:38:57 EDT 2005 | kamrant
Joseph, What is the topside temp reading of your board before reaching the pot? Do you have top-heater in your wave machine? It sounds like; you got an insufficient per-heating issue.
Electronics Forum | Mon Aug 01 20:02:20 EDT 2005 | Joseph
We use SAC305 and top side particular joint temp. is 110 deg C, and the terminal finish for that particular lead is pure tin. It look like hot tearing at the primary side of PTH.
Electronics Forum | Mon Aug 01 09:06:33 EDT 2005 | davef
Based on your description, it sounds like the solder connection is defective. Further description of board and solder materials and assembly processes would be helpful in moving forward.
Electronics Forum | Wed Aug 03 21:29:59 EDT 2005 | Ken
Yes, lead can promote fillet lift. In order to understand this defect you must begin looking at your lead frame mateials. some lead frames are more susceptable to this disorder. This is most likely a cte mismatch disorder. Lead contamination in
Electronics Forum | Tue Aug 02 22:49:55 EDT 2005 | davef
IPC-A-610D Section 5, shows a variety of photographs of: * Good lead-free solder connections * Lead-free soldering anomalies Hot Tear / Shrink Hole is one such anomaly. This shrinkage effect appears primarily on wave-soldered joints, but can also
Electronics Forum | Wed Aug 10 13:31:05 EDT 2005 | patrickbruneel
Joseph, In addition to my previous post The reason why the cracks are most visible at the transformer location is due to the weight of the transformer. The stress on the boards is the highest because the weight of the transformer will warp the board
Electronics Forum | Wed Aug 10 10:41:23 EDT 2005 | patrickbruneel
Bob, Great theory if you're selling SN100C, but I have to disagree that an alloy being 4�C off eutectic will cause cracks. When a solder joint exits the solder wave, there is an immediate drop in temperature of 100�C. so being off 4�C is irrelevant.
Electronics Forum | Wed Aug 10 09:01:15 EDT 2005 | fctassembly
Hello Joseph, Sorry for the bad news but microcracking is a well known potential condition occuring with the SAC305 alloy. Microcracking is a condition being seen with many joints soldered with the SAC305 alloy. It is technically a shrinkage cavity
Electronics Forum | Thu May 11 18:59:40 EDT 2000 | lboone
Have anyone perform wave soldering on FR-2 and FR-1 printed circuit board with lead free soldering? Can you share the parameters(wave temperature,preheat temperature, contact time, wave height,etc,) used and did you do any changes to the wave solderi
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