Electronics Forum | Wed Feb 03 11:31:20 EST 2016 | steprog
Hi, New to this forum. I am an engineer assigned to resolve a quality issue on our production line. It seems that we have been getting small droplets of flux on our boards after the reflow process. Occasionally, they land on a board to board conne
Electronics Forum | Thu Jul 26 09:47:30 EDT 2018 | vchauhan
Rob, Thank you so much for your suggestions. Vinod.
Electronics Forum | Fri Jul 27 09:58:33 EDT 2018 | vchauhan
Dave & Rob, You guys are great. Appreciate your help.
Electronics Forum | Tue Aug 14 09:32:46 EDT 2018 | vchauhan
Thank you so much.
Electronics Forum | Fri Jul 20 13:50:22 EDT 2018 | vchauhan
This question is regarding stencil design: I am having voids under QFN TI P/N LMZ20502SILT. I have attached component pic. Signal pin is 18X16 mils. Center pads are 31 mil sq. Initially I had stencil done with one mil per side reduction on signal pad
Electronics Forum | Thu Jul 26 04:26:59 EDT 2018 | Robl
Hi VChauhan, I'll preface this by saying I am no DaveF. Voiding can occur when the flux in the paste boils and vapourises, the expanding vapour needing somewhere to go displaces the paste. So... what we have done in the past: 1) Step the stencil d
Electronics Forum | Wed Aug 22 16:41:09 EDT 2018 | emeto
To all good suggestions I will add a few other thoughts: 1. Check PCB design(attached). THis mask clearance there is designed so you have some gas escape plan- verify if your PCB design follows that. 2. You can have a long soak reflow profile to re
Electronics Forum | Fri Jul 27 09:47:20 EDT 2018 | davef
Adding to Rob's suggestions ... One of the theories about voiding in thermal / ground pads of BTC is: Solder starts melting at the edge of the pad and moves inward towards the center of the solder mass. This traps flux volatilizes. So, there needs t
Electronics Forum | Tue Aug 14 08:19:45 EDT 2018 | buckcho
Hello, other colleagues gave you valid ideas. I found it helpful if i reduce the size of the cooling openings. I would suggest making the four big square into very small many diamonds. This would maybe decrease your voiding with 2-4 percent. Btw how
Electronics Forum | Mon Jul 18 12:24:53 EDT 2016 | oleksz
Some people involved in PCB assembly process claim that SMD components reflow soldering problems are often caused by traces running under a component. According to this claim, trace (or any copper) covered by solder mask and placed under SMD componen
