Electronics Forum | Fri Dec 22 16:04:26 EST 2006 | mika
Hi, This Not so easy as one wuold think. Has the thermal pad of yours vias? How many? What's the via's dia? What is the pcb thickness? If the the pcb has a "ground layer" connected (vias) to the pcb thermal pad, it could sometimes be a little bit tri
Electronics Forum | Tue May 02 15:09:40 EDT 2006 | PWH
Just a few problems you might have to deal with: 1) Your bare boards must be clean and kept clean though-out the process. You could notice handling contamination that might otherwise have been removed in your wash. 2) You will see solder balls a
Electronics Forum | Wed Oct 30 10:55:53 EST 2002 | ahobby
I hope you'll take an answer from the sunny UK. I don't usually read these forums but contribute to similar over here, hence the late response. We have an Invicta Sabre 757 machine in our Demo room, running with Zestron SD 300. We give the PumpPrint
Electronics Forum | Mon Oct 14 17:59:45 EDT 2002 | russ
When I used the micro-stencils, We purchased the holder from the stencil manufacturer. As far as design we used 5mil stencils for uBGAs,6-7 mil for larger 63/37 balls, and 8 mil for CBGAs. Aperture openings used were slightly smaller than what we wo
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 Apr 11 15:37:29 EDT 2005 | GS
For 1,27 mm Column Pitch, we set our process like this: - Stencil 0,20 mm If allowed also for other SMDs otherways some time 0,150 with step up stencil used only for CCGA area. - paste height min 0,175 mm - aperture 0,75 to 0,8 mm - paste volum
Electronics Forum | Tue Dec 22 14:29:08 EST 1998 | Earl Moon
| | I have a mixed technology board ranging from 50 mil pitch devices to 20mil Qfp's to PBGA-352 at 1.27mm, and 6 Intel uBGA-48 at 30 mil pitch. With all these different package types i'm torn between using a 4 or 5mil thick stencil. The ball dia. is
Electronics Forum | Fri Aug 03 14:55:26 EDT 2012 | davef
Not the best situation in the world, but you know that. Check with printer equipment suppliers [eg, DEK, MPM, etc] for a product called "Stencil Clean Wipes." Back in the old days, we'd: * Wipe the stencil with a solvent soaked wipe * Put the sten
Electronics Forum | Fri Nov 19 22:18:03 EST 1999 | mark
Laser cut offers the following two major advantages... the aperture tolerance is much better and the trapezoidal apertures are more consistant. For the small difference in price, you get the assurance of
Electronics Forum | Wed Mar 20 19:58:59 EST 2002 | davef
You based the aperture size on LxBxH. Where did you get the LxBxH? Obviously the thickness of the stencil is kinda fixed. Who gave you the other numbers? Consider searching the fine SMTnet archives for background on aperture design.
