Electronics Forum | Mon Jul 30 16:34:45 EDT 2007 | John S.
We're seeing shorting from the lead of an electrolytic cap to the can. It appears to be solder wicking up the lead, through the boot, and then shorting to the can. Has anyone else experienced this? It is a very cheap cap from China of course, but
Electronics Forum | Mon Apr 22 18:45:07 EDT 2002 | Steve Townsend
Chances are your profile is fine. There is probably too much paste on the descrete pads. Consider reducing the aperture size of the stencil. Good luck.
Electronics Forum | Tue Sep 01 22:41:13 EDT 1998 | Kelly
| Hi Kelly, | A couple of questions first. what type of BGA are these components? CBGA, PBGA, TBGA, etc. What is your aperture diameter on your stencil and what stencil thickness are you using? I think I can be of more help once I know the answer
Electronics Forum | Fri Sep 21 10:56:38 EDT 2001 | davef
Not as such. Look at IPC-7525 �Stencil Design Guidelines� The issues are: area and aspect ratios. They relate the size of the aperture opening to the thickness of the stencil. Check the fine SMTnet Archives for guidelines.
Electronics Forum | Mon Jun 06 16:32:51 EDT 2005 | nealh
I worked with our stencil vendor for a about a year tweaking our aperture guidlines for our printer. Of course we upgraded to a better printer and all of that went out the door. Work with your vendor and they should be able to make suggestion as to w
Electronics Forum | Mon Jan 09 08:25:30 EST 2006 | grantp
Hi, If the stencil was not cleaned well from the previous run, dried paste residue can cause the paste to grab in the stencil. If you have a microscope, check the small apertures for contamination. Regards, Grant
Electronics Forum | Fri Dec 09 15:10:55 EST 2011 | davef
Can you use the equipment manual as the basis for learning how to use the machine? Each model of printer has different alignment techniques. We don't have a clue of your model type. So, we'll approach the question from its most basic point. Registe
Electronics Forum | Tue Dec 17 20:25:13 EST 2002 | iman
Check : 1) design aspect ratio / are ratio required to fabricate the stencil you r using. 2) check if the stencil maker is using your checked aspect ratio / area ratio? if not the same, what are they using? any QA report confirming actual dimension
Electronics Forum | Fri Oct 14 17:08:36 EDT 2005 | Mika
What? That is easily done. With a 127 micron stencil thickness and apertures made for a QFP 0.5mm pitch... Remember from school of how You squeeze a media under a certain presure (like air), from a bigger diameter towards a smaller nozzle, You will i
Electronics Forum | Thu Apr 06 00:27:42 EDT 2000 | Dean
I would check their data sheet for the particular product. Thats the range I have for Some Kester products I use... Are you seeing any slumping prior to pick-and-place? Is the bridge in the same place every time? How is your pick-and-place mounting
