Electronics Forum | Fri Jun 12 21:36:04 EDT 2020 | SMTA-Josh
Has anyone had an issue with changing from a HASL surface finish to a LF HASL finish if it is still being used in a leaded process? Also we are having issues with the planarity on the fiducials with the HASL finish. Are there any suggestions or ch
Electronics Forum | Tue Jun 16 14:35:13 EDT 2020 | dwl
for the fiducials, try a donut shape instead of a disc. The HASL solder seems to settle more evenly on a donut than it does on a dic.
Electronics Forum | Mon Jun 15 20:37:29 EDT 2020 | travishemen
Try sending your boards to rework before SMT and have them remove the excess solder from the fiducials. It usually works great until someone accidentally removes the entire fiducial.
Electronics Forum | Sun Jun 14 03:02:14 EDT 2020 | kylehunter
We did a batch of boards with lead free HASL that we thought was leaded. Using standard leaded paste worked, but we did have some wetting issues. The issues were resolved when switching back to leaded HASL. Can't speak to your specific fiducial issu
Electronics Forum | Mon Jun 15 16:51:05 EDT 2020 | emeto
Tin/Lead has 183C melting point and probably around 220 peak temperature at reflow. Tin has 232C melting point. I would assume that based on this information you would understand why intermetallic joint is questionable. Go to any flat finish. HASL wi
Electronics Forum | Mon Jun 15 16:31:25 EDT 2020 | rgduval
You may find some wetting issues running LF HASL with 63/37, as your reflow temperatures will be significantly below the LF reflow. On fiducials...if you don't have a quote for your boards with ENIG, I would recommend at least checking it out. It's
Electronics Forum | Wed Jun 24 16:51:25 EDT 2020 | kumarb
Hi. Taking this from a total different angle - why not use ENIG to avoid this issue but find more competitive suppliers? We source from offshore all the time and finding that due to this dreaded virus - the market pricing is soft. Many are willing to
Electronics Forum | Wed Nov 28 02:43:00 EST 2007 | philip_yam
Hi all, For leadfree HASL finish, is there any specification or guidelines for contamination level, esp Cu% to refer? How can we ensure the HASL finish composition is reliable for assembly? Thanks..
Electronics Forum | Thu Sep 11 16:50:18 EDT 2003 | davef
Sure it's conceivable that thin HASL can cause tombstoning. Harkening back to the ample discussion in the fine SMTnet Archives, tombstoning is caused by an imbalance in solder surface tension between the two pads of SMT component. The source of thi
Electronics Forum | Fri Sep 12 09:10:23 EDT 2003 | Norm Morikawa
Around 1989 I had this probelmm with a SMT CCA that would not solder in one area consistently. I had it cross sectioned by the bare board supplier and found that under their metallurgical microscope the thickness of this HASL bare board could not be
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