Electronics Forum | Thu Mar 02 13:19:10 EST 2006 | Wave Master Larry
WELL, I heer that thikness was always wrong where I work, and for what ever reason the engineering department chose 6 milimeters. Personaly i would of gone 8 myself. I look under the magfying glass and always noticed in-suficient solder on the gull
Electronics Forum | Thu Mar 02 20:58:16 EST 2006 | pr
Dis agree?!?!?! We solder plenty of them o6o3s at honda and they l00k 0k! Solder balls will always fall off the b0ard when mounted anyway.
Electronics Forum | Mon Mar 13 04:18:42 EST 2006 | pedestrian
0.2mm gap between parts is small and easy to solder short. I prefer 5mils or 4mils.
Electronics Forum | Mon Sep 28 15:43:55 EDT 2009 | davef
Search the fine SMTnet Archives to find threads like: http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=39954
Electronics Forum | Sun Sep 27 22:39:55 EDT 2009 | rajeshwara
The same issue i faced 2 yrs before , i sugest 1. Use stencil of 4 mils ( Take care of Aspect Ratio and Area Ratio ). 2. Use Solder Paste of Type 4.5 and Viscosity in between 1100 to 1300. ( Try Solder Paste of Cookson or Alpha metals : OM338 T45-L
Electronics Forum | Mon Jan 23 22:53:31 EST 2012 | davef
= 0.66 aperture opening to the stencil wall has been shown to provide the best transfer efficiency and repeatability of the deposited paste. Values from 0.66 to 0.8 insure a good paste release from the stencil. The biggest impact on area ratio is the
Electronics Forum | Thu Mar 02 13:04:22 EST 2006 | Chunks
0603 parts at .2mm spacing is pretty easy. But are there any other parts, like fine pitch QFPs? Is your board HASL or something else? Is there resist/mask between all pads? If it's just 0603's at .2mm, then you can probably go 7 mils and get good
Electronics Forum | Fri Sep 25 16:47:57 EDT 2009 | esoderberg
0.5mm pitch QFP's are typically mixed with large components on all of my boards. I usually use a 6 mil stencil with a minimum aperture width of 10 mils. Normal aperture size is 10 x 50 which causes shorts about 20% of the time. A recent purchase of
Electronics Forum | Thu Jun 16 18:19:05 EDT 2005 | Jason Fullerton
If the uBGA has aperatures that are 0.25mm square, you need to use a laser cut foil no thicker than 3.75 mils to get an area ratio of 0.67, which is the minimum rule of thumb - that's too thin! Electroform would probably work up to 4.5 mils thick.
Electronics Forum | Thu Jun 09 13:30:34 EDT 2005 | PWH
I would suggest 7mm thick "Durostone" as a carrier material. Cut lip/pocket for PCB so it is 0.05" thinner than thickness of PCB. Allow 0.010" gap on all sides of PCB. Machine lip to width between 0.050" and 0.100" to support under perimeter sides
