Electronics Forum | Mon Jul 28 13:16:47 EDT 2008 | realchunks
Be careful of just reducing your aps. Too much can cause tombstoning if your print is slightly off or your placement isn't right on. Also be careful of the "pac-man" type of ap - it can lean to asty cuts if you wipe off your stencils by hand. Do
Electronics Forum | Tue Sep 16 10:51:09 EDT 2008 | rayjr1491
Here is the scenario: We are using Lead Free Type III paste. We are using 5 Mil EFORM stencils The part we are having issues with is a SOT883. Stencil design is the SMALL PADs are 10x16mil Large PAD 14 x 24 mil. We are getting some see-sawing of th
Electronics Forum | Tue Sep 16 16:55:51 EDT 2008 | rayjr1491
I am a doer myself but with the turn around and cost on EFORM stencils I prefer to be right and starting with math is always the best way. We have played with reducing apertures even stencil thickness as low as 4 mil. On the side that this component
Electronics Forum | Tue Sep 16 17:56:36 EDT 2008 | slthomas
"....over 3500 apertures in a circuit that is about 1 x 1.5 inches..." 8O Yeah, Larry would definitely be the go-to on this one. :P I would think reducing stencil thickness would be your best bet to avoid that ratio problem, but how durable is a .
Electronics Forum | Fri Sep 19 02:38:12 EDT 2008 | grantp
Hi, We would like to do low volume large boards, and does anyone know what options there are for stencil printing larger boards. The board we are doing is 412mm x 685mm so it's quite large. Pick and place is ok, just stencil printing. Is there some
Electronics Forum | Thu Nov 13 17:52:13 EST 2008 | dingstinger
My name is James and live in Colorado. Through an interesting turn of events lately I have gotten back into repairing coined PCB metal stencils. I am in a differant industry but have come up with a proven way to fix imperfections in metal stencils. W
Electronics Forum | Thu Mar 05 09:54:59 EST 2009 | davef
When you measure "solder paste heigth of 7 & 8 mils using a 5.0 mils stencil," are you measuring the top of a flat brick? Sometimes if you snap-off the stencil too fast, the paste touching the stencil walls form peaks along the edge of the brick that
Electronics Forum | Tue May 26 15:39:16 EDT 2009 | mikesewell
Amkor's MLF guidelines are very similar to Actels. 1 to 1 on the stencil to part pad on the I/O pads, 75% with a grid windowpane, 0.125 mm/5 mil stencil. For example, the Actel area ratio for a 0.3 mm sq. pad and 0.125 mm stencil is 0.6 which seems
Electronics Forum | Tue Jun 02 22:23:09 EDT 2009 | mikehe
Where do you getyour stencils from, ask them, I buy everything from DEK(Vector Guards) and they help me 100%. Apperture size, we always have cut 1:1 for the BGA's you can try 4mil stencils. But you have to keep in mind what the other parts you have o
Electronics Forum | Thu Jul 23 15:05:16 EDT 2009 | stephan
I look for an international standard for PCB stretch . In case of misplaced solder paste versus stencil we noticed shorts after placement . I found cases where the PCB (image pattern) did not match with the stencil . It was due to PCB or stencil str
