Electronics Forum | Thu Dec 13 15:14:07 EST 2001 | cc
Does anybody know what is the nominal thickness for via masking and is there a set max.? I recently have some bridging on some fine pitch components and my suspicion is that the new fab with new via masking is the culprit. Thanks CC
Electronics Forum | Thu Dec 13 20:54:23 EST 2001 | davef
There is neither �nominal thickness� nor �is there a set maximum� for via masking. We use some of our vias as test pads. So, as you�d expect, we get rabid when we get mask bleed onto these pads. IPC-6012 - Qualification & Performance For Rigid Pri
Electronics Forum | Mon Jan 11 14:48:44 EST 2010 | davef
SR1000 is commonly used for tenting. Search the fine SMTnet Archives on : tenting Someone gave us this note. We have lost their name. It seems to be good advice. If Liquid Photo Image (LPI) solder mask is required, do not tent via holes. Tenting
Electronics Forum | Tue Feb 01 21:53:06 EST 2000 | Dave F
Emmanuel: You have choices to prevent the solder paste from flowing to the second side during reflow: 1 Have your board fabricator plug the vias. 2 Put a temporary solder mask on the secondary side vias. 3 Have your designer relay-out the vias unde
Electronics Forum | Wed Jul 23 08:18:29 EDT 2008 | davef
Q1. Is this a standard process for plugging? A1. Not as such. We checked both IPC-6012 and IPC-SM-840. Neither comments on plugging. So, your fabrication notes rule the day. Q2. Is this okay for such thick PCB's or is it mandatory to use a special pl
Electronics Forum | Tue Sep 25 14:08:59 EDT 2001 | davef
Oooo, the solder on the pad and PGA ball is flowing during reflow down the via to the secondary side? Why didn�t you say so?? ;-) Why would you expect that gravity and capillary action wouldn�t force solder to flow down the solder plated via to the
Electronics Forum | Thu Jan 06 16:11:07 EST 2005 | Chunks
It appears your board house is having a problem with the solder resist (mask). From the couple pix it appear that the holes are being plugged by the mask, so your HASL is not able to be blown out during the hot knife process. Time to call your boar
Electronics Forum | Wed Jul 07 13:41:42 EDT 1999 | Dave F
snip | | If you go for plugging be sure you have a protrusion spec that you can live with. This often results in little bumps of epoxy that can interfere with component placement. For us, tenting .015 vias usually gets us about 80% coverage from
Electronics Forum | Wed May 19 11:50:32 EDT 1999 | Chris Nuttall
We care currently running into problems during our plug via process: At the moment we plug prior to soldermask (LPISM) using epoxy resin - plugging takes place from the component side - however we are seeing solderballs after solder level.This is cau
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