Electronics Forum | Mon Feb 26 12:26:43 EST 2001 | CAM
I'm working a problem and looking for your input. Here the deal: Two sided mix technology board. Test is using unmasked via points on bottom for test points. Our fab drawing states tent via points on top side. First set of board came in with no tenti
Electronics Forum | Mon Feb 19 13:04:17 EST 2001 | billschreiber
The ultrasonic frequency used in today�s stencil cleaners is usually a 40 kHz �sweep� frequency (also used on semiconductors and other sensitive cleaning applications). This frequency is not low enough to cause stencil damage (the lower the frequen
Electronics Forum | Mon Sep 17 15:27:51 EDT 2001 | jschake
Challenges: The basic defects that impact assembly yield are bridging, satellite solder balls, and opens (i.e. tombstones / draw bridges). There are many variables with the stencil printing process that can impact these; several of them are listed
Electronics Forum | Sun Aug 15 14:56:03 EDT 1999 | Dean
| One of the DFM suggestions I've seen is to remove the solder mask web, i.e. the mask between pads on 20-mil QFP devices. The rational is that if the mask is thicker than the pad the mask can prevent the stencil from making intimate contact with th
Electronics Forum | Thu Nov 16 22:01:16 EST 2000 | Early Moon
I promised never to do this - BUT only for you needy folks when I have nothing else to do. And Dave's basically a good person though not as needy as most really needing this stuff. 1) Ensure internal Gerber data really matches board and stencil (Ger
Electronics Forum | Wed Aug 22 19:54:54 EDT 2001 | mkallen
Can anyone point me to a relevant IPC spec that specifies an allowable board stretch, measured between metal features on outer layers (e.g., between fiducials and component pads on the topside of a board)? I've got a non-linear stretch problem that'
Electronics Forum | Fri Jul 09 11:28:24 EDT 1999 | Earl Moon
| Has anybody successfully used an automated dispensing system to put solder paste dots on .5 mm pitch pads?? I need to replace some Meritec tsop sockets and I don't want to use the single site stencils for .5 mm parts. | Carol, Don't blame you f
Electronics Forum | Wed Aug 29 20:20:19 EDT 2001 | Rob Fischer
What a great question! I know of just a couple: http://www.scancad.com http://www.lpkfusa.com/products/product/smtstencil/index.htm They've been around for awhile and must have a proven track record. I don't know if there is any governmental agency
Electronics Forum | Thu Oct 06 18:58:29 EDT 2005 | PWH
Holders and blades can be spendy. "JNJ" is good place to get aftermarket stuff (I have no affiliation with them). I've also found laser cut metal blades work fairly good and are cheap. Your stencil supplier might be able to cut them for you if you
Electronics Forum | Tue May 22 10:33:36 EDT 2012 | swag
In my opinion, the best solution is h-towers or similar dedicated tooling designed for each build. However, a quick cheap fix is to make templates to lay in the bottom of the centernest. If you have access to CAD software, you can print out the ger
