Electronics Forum | Fri Jul 15 18:21:55 EDT 2005 | dggjr
We have Kester 256 no-clean spec'd as an alternate paste. I bring some 256 in occasionally to make sure it still works as a backup. The last batch I brought in was bridging like crazy. Scraped it off the stencil, put our regular Alpha back down an
Electronics Forum | Sat Dec 20 23:13:14 EST 2003 | Dean
Hi Tommy. A clean printer has always been a hot button with me as-well. Solder paste is like a can of paint. As soon as you open it up you will get it on all the things you wanted to preserve as clean. The cleanliness and condition of your sten
Electronics Forum | Thu Apr 20 14:33:18 EDT 2006 | dirk29
We had that problem with our printers we just drill and tap the top end of the stop and put a short screw in to allow us to adjust the top height of the stop and catch the board. Be careful not to make it to long or to could restrict the board from l
Electronics Forum | Fri Feb 15 00:39:09 EST 2002 | Jones
I've noticed that after we have switched to Transition Automation blades on our MPM screen printers that the stencils seem to be wearing out faster and I see a wavy rippling effect across the length of the stencil thats impacted by the squeege blade.
Electronics Forum | Wed Jun 22 11:11:09 EDT 2005 | geb
Thanks for your help. I have resorted to using pads as the PCB doesn't have fids particularly close to the stencils fids. All previous jobs have had fids in the same place on the stencil as the PCB. The printer has a wiper paper which I have set to e
Electronics Forum | Sun Mar 26 19:02:05 EST 2006 | ms
Hi We are running automatic stencil printers, open squeegees, stainless stencil, stainless blades, print speed 25-30mm/sec. We have a frustrating consistency issue printing .37x.3mm apertures on a 45pin LGA (11 pads each side, 1 large ground in mid
Electronics Forum | Tue Aug 01 12:38:13 EDT 2006 | razor9114
I would go with a 5 mil stencil as well, we experienced some similar issues with micro BGA's and the area ratio was suspect as well as the MESH size of the paste. We went to Type IV paste and verified our area ratio and everything ran beautifully. Pa
Electronics Forum | Wed Oct 03 12:04:55 EDT 2001 | slthomas
When we found this to be a problem with some QFP 100's (.020" pitch, and our first experience with fine pitch - 48 of them on a 2-up panel), we saw that the solder was running up the leads during reflow and staying there, leaving the fillets thin or
Electronics Forum | Thu Oct 27 20:46:35 EDT 2022 | emeto
Also solder paste type, optimized printer parameters suitable for this paste, correct apertures design on the stencil, stencil thickness, proper AAR, mounting accuracy and placement profile, oven profile, board thickness and a few other.
Electronics Forum | Mon Aug 14 05:45:16 EDT 2023 | dimamalin
First, this is the result of bad printer setup. Adjust knife pressure, PCB gap, separation speed, tooling, and stencil cleaning. Pay attention to the coating of contacts pad and height of solder mask of PCB.
