Electronics Forum | Tue Mar 03 03:02:17 EST 2009 | emmanueldavid
25% out of Lands in PCB, Insufficient/Inconsistent Alloy deposition which causes for poor Tackiness between Device Spheres & Paste deposited. Also note that Aperture Opening Designs in Your Stencil draws a huge role for these defects. 4. Placement: P
Electronics Forum | Wed Sep 02 08:52:13 EDT 1998 | Justin Medernach
| | We are experiencing shorting on a BGA. The part has a 1mm pitch with a 196 I/O count. The problem seems to pop up without warning & disappear in the same manner. | | Our pad design is .020" diameter pads with .025" solder resist diameter. Th
Electronics Forum | Fri Aug 13 12:52:17 EDT 1999 | Steve Schrader
| Hello | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | 100 durometer blade. Getting "tails" on deposi
Electronics Forum | Fri Nov 13 12:08:46 EST 1998 | fraser
| | | I keep hearing about polyimide stencils, but what are they like in terms of registration and aperture accuracy? | | | | | Fraser- | | | | We use polyimide stencils with great success for our prototype boards. They are cheaper and the acc
Electronics Forum | Thu Aug 12 20:31:57 EDT 1999 | Kelly Morris
| | Hello | | | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | | 100 durometer blade. Getting "tails" o
Electronics Forum | Thu Aug 12 20:48:05 EDT 1999 | JAX
| | | Hello | | | | | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | | | 100 durometer blade. Getting "
Electronics Forum | Thu Aug 13 14:10:01 EDT 2015 | markhoch
Hi Sam, I have a feeling that what you're trying to communicate is that your DPAK's are skewing off the pad during reflow. This is caused by a thermal "mismatch" where the solder paste on one side of the DPAK becomes molten before the other, then th
Electronics Forum | Thu Apr 01 15:10:33 EST 1999 | Brian
B: Are you electropolishing your apertures? With a finish of this type you can come close to Laser cut's smoothness. | We make an excellent chem-etch stencil. Our customers have had success printing 16 mil pitch without a problem. This is not an ad
Electronics Forum | Fri Aug 17 09:32:36 EDT 2012 | jeremymek
I would advise against using IPA for stencil cleaning It may initially seem to produce good results but the way it works you end up with more problems. IPA is good at removing liquid fluxes but it dries out and cements solid fluxes to the stencils
Electronics Forum | Thu Jul 20 13:28:13 EDT 2000 | Bob Willis
On all the trials I have done I have made no changes to the stencil thickness or apertures than the normal changes we make for our process. I have not changed any thing in terms on volume of solder for more reliable joints. I fact I have not read any
.jpg)