Electronics Forum | Tue Dec 05 03:39:39 EST 2006 | pavel_murtishev
Good afternoon, Due to problems with power connector soldering I have to overprint paste on pads for this connector. Stencil thickness is 125um and I cannot make it thicker. Area ratio of chip resistor assemblies limits stencil thickness to 125um. R
Electronics Forum | Tue Dec 05 08:23:14 EST 2006 | davef
How about a stepped stencil? Not ideal but ... As far as overprinting goes, try: http://www4.uic.com/wcms/WCMS2.nsf/index/Resources_44.html
Electronics Forum | Wed Dec 06 06:09:02 EST 2006 | Loco
Would say about the same as above, 8mm according to a cookson presentation we had, of course it would depend a bit on the paste you are using.
Electronics Forum | Wed Dec 06 16:17:31 EST 2006 | Mario Scalzo, CSMTPE
Normally, we try to limit the over print of the paste to the width of the pad on both sides. If you are using 500um pad, then I wouldn't try over a 1500um aperture. Mario Scalzo, CSMTPE, Dartmouth 6 Sigma Green Belt Technical Support Engineer - Ind
Electronics Forum | Wed Dec 06 08:29:50 EST 2006 | David
Hi Pavel, We regularly use over printing on a multitude of problem parts including fine pitch QFP's. In an Automotive Environment the only thing you can change without a mountain of paperwork is the stencil. best way to work out how much you can get
Electronics Forum | Wed Dec 06 07:24:22 EST 2006 | davef
Successful solder paste overprint is a function of the solder paste rheology, solder mask and through hole component stand off. * Solder mask with a high surface energy will permit a larger overprint than a solder mask with a lower surface energy. In
Electronics Forum | Thu Feb 21 12:02:03 EST 2013 | pbarton
We agree with all of what Patrick has said. Hopefully your equipment is capable of the ideal setup you describe with no back flow until the product hits the wave and then back flow until the product emerges the other side. One other reason to strive
Electronics Forum | Wed Feb 20 18:21:49 EST 2013 | caurbach
A question for all you wave experts out there: We run our wave with a constant flow over the back plate. I know it's recommended that we set the back plate so that the solder sits just at the top of the back plate with surface tension keeping it fr
Electronics Forum | Fri Feb 22 14:29:55 EST 2013 | patrickbruneel
Caurbach, Higher preheat and longer dwelltime will fix your problem.
Electronics Forum | Thu Feb 21 10:11:36 EST 2013 | patrickbruneel
The backflow in the wave started to become very important with the development of no-clean/no residue fluxes. These fluxes don’t have (or at least shouldn’t have) rosin, resin or other vehicles in the formulation which encapsulate surface oxides from
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