Electronics Forum | Fri Sep 24 09:49:53 EDT 1999 | C.K.
Hi Folks: We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. The bridging is happening after coming out of reflow...one last thing t
Electronics Forum | Sun Sep 12 09:40:04 EDT 1999 | Wayne S.
hello having a problem with one customers bare boards not matching my stencil apertures. i design stencils based on gerber data and reduce up to 15% on some pads. do some board houses reduce pads after receiving gerber data???why would they do that
Electronics Forum | Tue Jul 27 06:08:18 EDT 2004 | C Lampron
Good Morning Everyone, Could someone please tell me what the acceptable range is for HASL plating thickness. We have some raw boards with plating thicknesses ranging from 3-4 mils on a fine pitch QFP. We are expeiencing bridging at this location an
Electronics Forum | Wed Aug 17 16:09:08 EDT 2005 | pjc
A skilled hand-soldering operator can easily do the rework. Applying liquid flux and raking the iron tip across the leads removes bridges. Removal and replacement of QFP-64 can be done manually. This is of course for very low volume of this type QFP-
Electronics Forum | Wed Sep 19 21:04:57 EDT 2007 | wailiang81
Hi,davef, thanks for your concern. The condition was the pasted printed off with around 0.8~0.9mm from the land pattern. This will easy observe at QFP area. At fiducial, the stencil seens aligned accurately. Once solder bridge happend, its easy to
Electronics Forum | Sun Oct 08 00:18:05 EDT 2000 | Arturo
We are working with a 16mil TSOP Land width=0.2mm(8mil) and use: 1.Type 4 particle size solder paste. 2.Laser cut electropolished stencil: Aperture width=0.19mm (we tried lower than this but had solder insufficiency). Thickness=0.005"(130 microns)
Electronics Forum | Sat Dec 11 12:15:21 EST 1999 | Steve Thomas
We have a pretty challenging board (2-up panel, 15"x20", 48 20mil pitch QFP 100's and 2 25mil QFP128) that gives us LOTS of lead bridging on the 20 mil parts. There is typically very poor wetting on these parts also, and some joints just flat aren't
Electronics Forum | Fri Jul 16 15:22:27 EDT 1999 | SMTASSY
We are currently looking at purchasing an AOI equipment but would like facts from present users of such equipment. Our envirronment is as followed, - Runs from proto to 5000 boards of the same type. - 20% PTH, 60% Mixed (with some BGA) and the rest
Electronics Forum | Wed Oct 10 13:49:12 EDT 2001 | stepheno
I recently started at a new company. They have a variety of bare PCB's and most have aprox. 20 variations. Maybe about 1/3 of each board on average are non-populated locations. They buy one stencil for each PCB but then use scotch tape to block of
Electronics Forum | Fri Jan 08 22:39:22 EST 2010 | graceytiu07
Thanks for the reply. I'll try your suggestion. I tried the SEM EDX to check for traces that might cause the bridging problem but it looks normal. I haven't tried yet the material level analysis of the QFP. Thanks again.
