Electronics Forum | Wed Jan 30 17:23:07 EST 2013 | dyoungquist
In response to hegemon... This is not a recommended practice but..... We have added a few drops of water soluble flux to our water soluble solder paste when the paste is on the stencil. This was after the paste had "dried" out a bit. We have had
Electronics Forum | Fri Dec 01 12:02:15 EST 2000 | blnorman
I have over 10 years experience in aerospace materials, part of which was involved with vacuum casting inert propellant formulations. These propellants are in the range of 80 - 90% solids loaded with viscosities of 15 kP. I'm not sure where I could
Electronics Forum | Wed Apr 14 05:44:36 EDT 2004 | hun
Hi All, Just have a share with you guy. We are using T4 solder paste and also E-Stencil. We ahd try out Alpha, Kester, AIM and Qualitek. The result show Alpha had a very very heavy stack flux and can't get it clean off even by chemical
Electronics Forum | Thu Apr 29 11:07:03 EDT 2004 | arcandspark
You are right about the very poor support for smaller customers. I had told them we were looking for another paste and now they have sent the reginal manager and the US sales manager has come by to see what they can do for us. All they keep saying is
Electronics Forum | Wed Mar 30 15:15:03 EST 2005 | chunks
This is a pet peeve of mine. The paste height requirement is generally asked because the customer has no clue about screen printing, but knows to ask this question. If he did know even a little about printing, he�d ask you to assure the �volume� of
Electronics Forum | Fri Apr 27 11:24:53 EDT 2007 | realchunks
Hi Steve-O, Good question(s). This process was set-up by an engineer that had a PhD in statistics, took him a year to develop and then thru it over the wall at us. The biggest problem we saw was SPC to measure solder volume. SPC is good for measu
Electronics Forum | Mon Mar 27 20:34:22 EST 2006 | ms
Thanks for the suggestion. The large ground pad appears as a single large pad on the component and PCB but we print a matrix of 28 small dots of paste to provide the solder for the joint. The inconsistent volume transfer can occur on any of the fo
Electronics Forum | Fri Apr 22 15:59:42 EDT 2005 | Valerie
Besides poor printing using cold solder paste will also cause solder beading.
Electronics Forum | Fri Dec 20 11:32:51 EST 2002 | D. Adams
Check your stencil apertures making sure they are trapazoidal and smooth. I have hadjobs where the laser stencil was improperly cut (poor laser settings leaving a rough hole even after electropolish. Be sure to specify a .0005 trapazoid in your ste
Electronics Forum | Tue Sep 18 19:32:49 EDT 2007 | davef
Welcome Jimmy Let's mince words to help focus on the issues. When you say "QFP area solder paste shifted," do you mean: * Paste printed on land pattern perfectly, but moves after printing. * Paste printed off the land pattern, even though the stenci
