Electronics Forum | Thu Oct 02 08:26:41 EDT 2008 | rway
We had similar issues until we went to a 6 mil stencil thickness.
Electronics Forum | Mon Sep 29 11:44:39 EDT 2008 | manishc
We r facing less soder problem with qfp,using 4 mil tencil and lead free paste,tried out different combinations of reflow profile,can anybody suggest?
Electronics Forum | Mon Sep 29 14:47:15 EDT 2008 | davef
Let's narrow this down. Questions are: * Are you putting the proper amount of solder in the board with your stencil print process? * If you are putting the proper amount of solder in the board, where is the solder going? Pick one and then fill-in th
Electronics Forum | Tue Sep 30 14:06:04 EDT 2008 | realchunks
What pitch? You can go 5 mil or even 6 mil stencils depending on your screen printer. Also what do you consider "less solder"? What defect are you having. Remember on a QFP you use the heel filet to determine proper solder joint - not the toe.
Electronics Forum | Sat Jun 18 00:35:15 EDT 2005 | mskler
Thanks to all. I am working on your suggetions will get back as the problem solved
Electronics Forum | Thu Jun 16 00:24:29 EDT 2005 | mskler
Hi everybody, Can some body tell me that what stencil thicknes is required for the 16mil QFP. I am getting bridging as well as dry at QFP pins. What type of solder 1. Viscocity 2. mesh size 3. flux contents Should be used for this type
Electronics Forum | Thu Jun 16 08:31:15 EDT 2005 | jh0n!
The most part I have the most difficulty with is a 16mil QFN. We found that reducing stencil thickness to 4mil, and reducing aperatures for the IC by 20%, and setting local fiducials to the IC helped immensely. We used to get 75% or more bridged ou
Electronics Forum | Thu Jun 16 22:14:51 EDT 2005 | davef
16 thou pitch parts: Use a 5 thou laser cut electropolished stencil with 0.008"x0.045" apertures and type 3 solder paste. Bridges Connecting or Partially Connecting Adjacent Leads or Lands * Excessive solder paste * Excessive component placement pre
Electronics Forum | Thu Jun 16 09:13:46 EDT 2005 | russ
We use a 5 mil for 16mil pitch QFPs, Make sure that the stencil has been polished. Type 3 paste. We have used lead free no-clean, lead no-clean, and water soluble lead pastes for these packages. We set the printer for a slow stroke .7 in/min. wi
Electronics Forum | Mon Sep 25 16:14:16 EDT 2000 | LarryK
What do you all do to fix coplanarity on fine pitch QFPs? I know that the best thing would be to send them back to the vender, but what about the when you gotta use them? Straightening by hand seems to be so time comsuming. Any better ways? Larry
