Electronics Forum | Tue Jul 11 12:59:26 EDT 2006 | mattkehoe@sipad.com
We are trying to apply solder to boards with 80 microinches of electro plated hard gold. No components involved, just print 63/37 paste and reflow. The results are very poor on some boards, not so bad on others? Pictures at http://www.sipad.net/thick
Electronics Forum | Wed Jul 12 11:26:12 EDT 2006 | flipit
Hi, I believe you have classic gold imbrittlement here. With 80 microinches of gold you are way over the limit. You can try to reflow longer time and at a higher temperature. The gold does not melt into the solder joint. The gold dissolves into
Electronics Forum | Wed Jul 12 11:46:00 EDT 2006 | flipit
Hi, One other note. You don't want gold to be more than 1% to 2% of the the solder joint. Above this percentage you will have embrittlemant issues. Lots of information on gold embrittlement on this site and on the Internet. I estimate your produ
Electronics Forum | Tue Jul 11 14:09:54 EDT 2006 | Chunks
Not reflowing completely. Slower = hotter. Try a slower conveyor speed.
Electronics Forum | Tue Jul 11 20:13:05 EDT 2006 | davef
We agree with Chunks. You need to turn-up the heat [slow the conveyor] because you have significantly changed the melting point of the solder alloy by adding so much gold. Relative to ENIG you should expect: * Similarly smooth surface, possibly a l
Electronics Forum | Tue Jun 28 10:51:32 EDT 2005 | mattkehoe
Thanks for the replies, - solder paste used ? NC ? other ? Water soluble 63/37 paste - reflow in Air or N2 ? Infrared - temp ramp up before soack (�C/second) ? Will have to check. This profile has been used on numerous gold plated boards in our
Electronics Forum | Sun Jul 29 08:36:39 EDT 2001 | davef
You have provided very little information. Two similar possibilites come to mind: poor pad solderability protection and old boards. POOR SOLDERABILITY PROTECTION: Maybe the nickel plating under the gold is oxidized, contaminated, or otherwise very
Electronics Forum | Sun Jul 29 23:58:08 EDT 2001 | Frank
Hi Dave Thanks for your information. The problem that I found is paste not stick well on pads ( solder paste printing process). When the table move down (PCB saperate from stencil) some of paste stick on aperture instead pads. Solder paste : Delta
Electronics Forum | Mon Jul 30 21:12:32 EDT 2001 | davef
"Poor release" (paste hanging-up in the stencil holes) could have three main (or combination of) causes: 1 Equipment: Stencil is too thick. Specifically, a 6 thou stencil should be OK, providing you don�t violate the area and aspect ratios in the fi
Electronics Forum | Tue Jul 31 00:48:55 EDT 2001 | Frank
Sorry I forgot to provide enough information. Stencil thickness is 6 mil Aperture width is 10 mil Aspect ratio (aperture area / wall area) = 0.72 Solder paste mesh size, type 3 (-325 +500) With this aspect ratio we can printing without any probl
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