Electronics Forum | Mon Dec 22 18:20:33 EST 1997 | Graham Naisbitt
Brett and Chis, The method I understand to be the most popular is the use of micro-blasting or abrasion. In other words mechanical rather than chemical removal. However, that is only part of the problem - how do you repair the coating? The technique
Electronics Forum | Fri Aug 13 12:52:17 EDT 1999 | Steve Schrader
| Hello | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | 100 durometer blade. Getting "tails" on deposi
Electronics Forum | Tue Aug 17 10:41:13 EDT 1999 | Steve A
Wayne, Sounds like a gasketing problem. When the horizontal apertures are bleeding but not the vertical apertures. Could be poor underside support, HASL miniscus issues, masking or plugging issues, but what many people do not account for is that t
Electronics Forum | Sat Aug 22 12:18:12 EDT 1998 | Tryin'
| Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. So when in the process is HASL performed?? | With tin/lead plated boards,
Electronics Forum | Thu Mar 28 15:53:49 EDT 2019 | SMTA-Jon
As a CM, we don’t have a lot of input on the PCB layouts we receive. Some engineers/software packages output the paste layer 1 to 1, some do an across the board reduction, and some set each part up individually with different reductions per footprin
Electronics Forum | Fri Jul 07 09:15:23 EDT 2000 | K. Chak
Hi Dave, This particular p/n calls for print&etch for wet process..and the problem occured due to surface contamin. with resist residue resisting copper from etching off. The high pressure nozzle was a problem at developing oper. and it is fixed now
Electronics Forum | Wed May 10 01:00:09 EDT 2000 | gary
0.65mm pitch QFP. I believe that this is the borderline for Fine Pitch. Will I have a good paste release with Chem-etch matched with a rubber squeegee? I'm planning of a 15% reduction on the Width and no reduction on the length. Any feedback whether
Electronics Forum | Thu Apr 25 18:32:25 EDT 2002 | Shawn
What he is talking about when he said "foil" is the top and bottom side of the board has a layer that is like a ground plane with no solder resist covering it. It is etched out around the pads that no not need a connection and have a small bride or t
Electronics Forum | Thu Jun 08 22:54:31 EDT 2006 | hunghung
Dear all, If a PCB board, 2 mils of core with 1oz copper at the top and bottom, is it a good board to be fabricated? will it be caused warpage during etching for inner layer process? if yes, what is the real factor caused to warpage? How to solve t
Electronics Forum | Tue Jun 03 01:03:04 EDT 2008 | daxman
Hi, I think what you are describing is a half-etch QFN, which causes the 3 mil gap. In our process, we don't require solder to bridge this gap as it's internally connected to the bottom lead. I'm not sure if this is the question you're asking, but
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