Electronics Forum | Fri Dec 10 02:26:16 EST 1999 | Tracy Guo
Hi, I'm facing smear after printing on DEK288 using reverse squeegee at the edge of panels. I've checked the fixture, printing parameter, stencil, solder paste. What else can I do?
Electronics Forum | Fri Dec 10 12:06:35 EST 1999 | Gary Kemp
Tracy, I would check the squeegee blade for wear at the edges. Also, check the squeegee pressure to ensure it is not to high, forcing the paste between the stencil and the land, causing a smear. Good luck.
Electronics Forum | Wed Dec 15 15:51:42 EST 1999 | cb
Tracy, Gary made some good points, you could also to check to see if you have the printer taking a long enough stroke over the board. I have seen some people not have the squeege come across the board enough and the paste roll is still setting over
Electronics Forum | Tue May 02 05:59:28 EDT 2006 | davef
We agree with Ken's points about off contact / screen versus stencil, but this DHolt is talking stencil [regardless of what is typed about screens]. Comments are: * On "smears under the stencil": smearing happens. It makes us wonder about the frequ
Electronics Forum | Wed Sep 09 09:38:53 EDT 2009 | patrickbruneel
Dave is correct (as usual). Baking the boards might reduce blowholes but will definitely not eliminate the problem. Back in my hay days we had a huge problem with blowholes and we baked boards 24/7 with very little success in reducing blowholes (ev
Electronics Forum | Fri Oct 15 11:32:04 EDT 2010 | patrickbruneel
Inspecting for plating problems shouldn’t be part of incoming inspection. Your board manufacturer should have the appropriate process control. I shouldn’t have said barrel cracks but plating skips. Plating skips are caused by dull drills or a too hi
Electronics Forum | Thu Dec 16 06:06:52 EST 1999 | Stefan
Check the print gap and check the clamp edges, sometimes the clamps is damaged causing a distance between the PCB and the screen. Good luck
Electronics Forum | Tue Jan 28 17:23:11 EST 2003 | C. M. Gabel
I am working with a BGA package. The laminate layer is being modeled as BT-Cu smear. The thermal conductivity of BT is 0.19 W/mK. Does anyone know what the density and specific heat values are for BT?
Electronics Forum | Tue Jan 28 17:28:02 EST 2003 | C. M. Gabel
I am working with a BGA package. The laminate layer is being modeled as BT-Cu smear. The thermal conductivity of BT is 0.19 W/mK. Does anyone know what the density and specific heat values are for BT?
Electronics Forum | Wed Jul 28 00:12:48 EDT 2004 | NTV
It would be uncontrolled reflow process. Solder paste smeared, outdate solder paste, contamination, and many else could lead to this issue. A longer time reflow window would help elimating it (make it max. of 60 seconds liquid time).
