Electronics Forum | Thu Jun 02 10:54:12 EDT 2011 | davef
Al: We agree with AVFOM. You have a different problem than solder paste mesh selection. Most often, tombstoning occurs when the wetting forces on the two pads are unequal. Examples of things that can cause this are: * Pads are different * Board pad
Electronics Forum | Tue Jun 01 10:15:29 EDT 2004 | davef
We agree with John about his comments on the controlable factors relating to your printer, but we'd add that paste formulation and mesh are also contributors to nice looking bricks.
Electronics Forum | Wed Aug 29 03:16:20 EDT 2018 | cannizzaro
It is recommended that the thickness of the stencil of 0.1mm, the steel mesh should be partially nano-coated. It is best not to dry easily, and the particles are not easy to be too large. I have tried ALLPCB for this kind of BGA in the past and they
Electronics Forum | Thu Mar 04 07:35:38 EST 2010 | rajeshwara
Plz tell me Stencil Thickness ? Solder Paste ? Mesh Size ? Partcle size/type? Viscosity?
Electronics Forum | Wed Dec 19 16:53:41 EST 2007 | flipit
Double pass printing for solder paste is not needed and will cause defects. Redesign your stencil thickness or aperture sizes, change your paste mesh size or type, go to 45 degree blades.
Electronics Forum | Thu Dec 09 15:35:32 EST 2021 | saberbouras
Thanks, I wish all SMT quality people have the same thinking.
Electronics Forum | Mon Dec 20 17:23:48 EST 2021 | emeto
For tool accuracy, you use calibration labs.
Electronics Forum | Thu Dec 09 21:46:22 EST 2021 | dwl
Totally agree with Evtimov. Let the SPI be the judge, as long as your getting good prints, your stencil is fine. I had a colleague cut the mesh on one side of a stencil and it still printed fine. This was proof to management that measuring tension w
Electronics Forum | Thu Jul 20 12:16:26 EDT 2000 | Dave F
Bob: On "paste push-out" (when inserting a component lead into a through hole pushes the paste out of the hole) in pin & paste assembly: * What factors affect paste push-out? * What techniques reduce this effect, given a board design and component
Electronics Forum | Thu Aug 29 13:03:13 EDT 2002 | lysik
You have may have already checked this but verify stencil design (aspect ratio) and make sure you are using the correct paste (mesh size) Also look at perint pressure. up to 2 lbs per inch of blade used. You may also want to use a slow break away whe
