Electronics Forum | Wed Aug 28 11:52:24 EDT 2002 | lysik
What kind of print problems are you Having? Off pad, Voids? Or is it slumping, etc? You really should be all set with OSP boards. If I can get some more specific info I could probably help.
Electronics Forum | Fri May 26 08:16:14 EDT 2006 | Chunks
This could be what we call a "non-problem". If your print is off slightly, yet after reflow there is no solder related defects, it should be considered OK. Move your inspector from the printer to right after the oven. This would enable them to ins
Electronics Forum | Wed Jan 08 14:36:44 EST 2003 | davef
It depends on your product requirements. We don't like to print off-pad, because: * Tough to control the amount of paste that squirts onto the board, because the aperture is not gasketed to the pad on the board. * Some paste that squirts between the
Electronics Forum | Thu Jun 24 11:54:36 EDT 2004 | rickw
many solder-ball issues can be resolved by reducing the aperture size, usually 10 to 15% reduction will work. If the aperture size is the same as the pad size paste tends to be squished out under the part, paste off pad under the part will liquify a
Electronics Forum | Mon Jun 28 16:18:44 EDT 1999 | Earl Moon
| Hey there gang, how's it going ? | | Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's ar
Electronics Forum | Fri Jan 15 08:43:43 EST 1999 | Mike McM
Bernie, If the pads are for a chip component and only about a half a pad off without anything else in the misregistered area, go ahead and use the stencil as is. Surface tension of the solder at liquidus should cause it to wick back to the pad, even
Electronics Forum | Fri May 26 05:49:09 EDT 2000 | Richard Wilders
1.67. A lower accuracy will result in many off-pad flipchips; this means a lot of displacements. And there is no chance at all the flipchip will self-center back to the correct placement spot. I think you'll have to evaluate machinery that is capabl
Electronics Forum | Thu May 25 18:41:15 EDT 2006 | russ
How accurate is your placement machine? if it is accurate I would eval up to 25% off pad. the problem I might think you will have is errant paste or balls causing shorts if it doesn't coalesce completely. Bottom line is, if the board is good at th
Electronics Forum | Mon Dec 18 08:52:57 EST 2006 | russ
You need to get yourself a copy of IPC 610. this has all the specs regrding placement and registration. chip aprts are allowed to have 50% side overhang. the fillet requirements are "evidence of wetted fillet" . I would not know if a cap being 51
Electronics Forum | Mon Sep 10 10:21:42 EDT 2007 | mgrimes
Having a problem with a MPM AP/A. Once a board is programmed; all is calibrated and the first board screened - each board thereafter drifts and gets progressively worse. The drift can range from barely off to half off the pad. Any ideas?
