Electronics Forum | Wed May 07 01:50:03 EDT 2008 | andrzej
We have received in one lot PCBs with defect of not wetting properly. Pads were finished with HASL but they were matte rather then shiny (attachment). For me looks like they are oxidized. Interesting is there was just top side with such defect. We h
Electronics Forum | Fri Jul 30 14:50:26 EDT 1999 | Kevin Hussey
| I received a request from customer to assemble ceramic substrate (alumina oxide)that printed with a low temperature Copper thick film conductor (the overglaze layer is polymer). The Copper pads are exposed without any coating. | This ceramic substr
Electronics Forum | Tue Mar 28 08:29:04 EST 2006 | davef
Pad design - Standard IPC 20 pitch QFP Thermal pad design - Layout the thermal pad 0mm to 0.15mm larger per side (0mm to 0.30mm larger overall) than the exposed die pad on the package. �Larger than�, as opposed to the same size, is preferred. Obvio
Electronics Forum | Mon May 14 14:51:36 EDT 2001 | Brian W.
Personally, I prefer the OSP. I get a flat surface to deposit paste on, resulting in more consistent solder paste volumes. With HASL, the amount of plating and the mounding affect the paste deposition. I have even had it affect the placement. The
Electronics Forum | Thu Feb 27 02:55:53 EST 2020 | hexton
I want to avoid peoples preferences as they will differ and will not be a deciding factor. A heat gun will introduce risk to surrounding PTH components and having to add protection for those, will limit any gain in productivity. There is no question
Electronics Forum | Mon May 14 17:12:20 EDT 2001 | davef
Continuing along the path that Brian took ... IPC-7525 gives design guideline for stepped stencils. It goes something like: * Stepped area SB GT 25 thou from pads located on the greatest thickness of the stencil * Pads in stepped area SB GT 35 tho
Electronics Forum | Tue Sep 01 19:31:36 EDT 1998 | Kallol Chakraborty
| We are experiencing shorting on a BGA. The part has a 1mm pitch with a 196 I/O count. The problem seems to pop up without warning & disappear in the same manner. | Our pad design is .020" diameter pads with .025" solder resist diameter. The ce
Electronics Forum | Fri Sep 22 09:45:26 EDT 2006 | bradlanger
Greg, All the above. It looked like it was going to be a drop for SNPB HASL at first but after a few thousand boards we started running into all the problems you are describing. We first started seeing non wetting on SMT pads. The solder would wet t
Electronics Forum | Thu Feb 17 10:14:40 EST 2000 | Jim N
We bulid many boards with fine pitch on solder side and then wave. We use a wave fixture that is custom for each board. The fixture covers the SMT components and only exposes the PTH lead during the wave process. It requires about .070 to .100" clear
Electronics Forum | Thu Mar 15 06:26:26 EST 2001 | Sal
Sorry for the lack of information provided, I'll try again : Test Points are the one's that are not soldering. The test points are round in geometry, 0.5MM(metric) in diameter with a HASL finish.The test point are no different to the ed through hole
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