Electronics Forum | Thu Jul 17 00:22:37 EDT 2008 | jmann30
Manncorp offers brand new high quality stencil printers that hold 29 x 29 frames and sell from $15,000 for batch machines and under $30,000 with inline conveyor. There is no reason you need to spend more then this as these printers have very high acc
Electronics Forum | Mon Jul 21 09:57:29 EDT 2008 | davef
We use a ministencil with a QFN pattern that is very similar to the orginal stencil. Here's a link to one of the better white papers on QFN rework: http://www.intersil.com/data/tb/TB389.pdf QFN with less than a 2 thou standoff are less reliable tha
Electronics Forum | Tue Aug 12 07:35:23 EDT 2008 | stevezeva
Hi, Is the footprint per the component manufacturers recommendations? The reason I ask is because it kinda looks like the pads are extending beneath the component. Could cause the part to float up on top of the solder and not allow the leads to wet
Electronics Forum | Mon Aug 18 13:37:23 EDT 2008 | realchunks
We do it all the time for air pressure reasons. Use a 6 mil stencil, print right on the via, aperture opening 100% same size as the via, on an 0.063" thick board. Doesn't leave a bulge and plugs the air. You can have your board house do this for y
Electronics Forum | Thu Sep 11 11:47:15 EDT 2008 | jeffcali
Depending on the assembly, I have applied balls on LGA's and reflowed them on using the rework hot air machine. Some places don't have the money to spend on mini micro stencils of all types, and thus spend the money on various sizes of solder balls
Electronics Forum | Fri Sep 12 17:58:30 EDT 2008 | robinj
Can someone let me know what is causing this black coloration around the pads? It is on the edge of all pads all over the board. The surface finish is OSP. I don't have any solderability issue. But the stencil printer is having trouble with picking u
Electronics Forum | Tue Sep 16 13:40:20 EDT 2008 | ck_the_flip
Try reductions in the "Y direction". For the SMALL PAD, go from 16-mils to 14-mils, and on the large pad, you can play around with reductions on the 14x24mil pad...or try mesh pattern. You'll be well with area-ratio guidelines with both approaches,
Electronics Forum | Tue Sep 16 16:47:32 EDT 2008 | wavemasterlarry
All this nonsence talk of ratios drives me nuts.you guys should be do-ers and quit reading all these whitepapers. I fancy myself as be-ing from that school of hard knocks.No math or ratios needed for that. Speaking of hardknocks I'm in the Texas area
Electronics Forum | Tue Sep 23 07:27:31 EDT 2008 | realchunks
Do not wipe the board at first before putting it in your cleaner. It will leave more paste in your tank, but you won't smear it into every corner of your solder resist. We found that only our stencil cleaner would clean a board properly and leave n
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.
