Electronics Forum: board (Page 476 of 1565)

Double sided BGAs

Electronics Forum | Thu Jun 23 08:58:00 EDT 2005 | Irene Taylor

We are defining a new assembly process for a double sided card that has 26 BGAs on the top side and 14 BGAs on the bottom side. We currently have one double sided BGA board with one BGA per side and have to epoxy one BGA (35mm X 35mm - 352 ball count

Double sided BGAs

Electronics Forum | Thu Jun 23 10:43:40 EDT 2005 | davef

It wouldn't surprise us [too much] if this part wouldn't stay for second sided reflow. * If the lead contact area to weight is less than 44 gm / inch^2 [we know the units are goofy, but convient], it'll stay. * Alternately, just run a scrap board a

How to improve the solder quality of QFN?

Electronics Forum | Fri Jun 24 07:02:35 EDT 2005 | davef

Problem 1: Solder shortage * Stencil aperatures [except the heat slug] should be 1:1 with the board. * Stencil should be 5 thou thick laser cut. * Board should be 1:1 with the component * Print should look good. Problem #2: Bad connection between p

How to remove paint from back of PCB without damaging ?

Electronics Forum | Sat Jul 09 11:31:14 EDT 2005 | techvet99

I have several circuit boards (about 14" by 16" in size) that I recently acquired and am trying to repair. One problem is that the former owner painted (spray paint I think) the word "TEST" in big red letters covering most of the solder side of the

Need help on selecting the SMT equipment for small volume

Electronics Forum | Fri Jul 15 06:50:02 EDT 2005 | Rob

It looks like the 330 Convection & the GF120 ovens would really stuggle to do lead free, with 3 zones (the 330 has 3 top, 1 bottom). Can't comment on the 545 oven, you'll have to get them to run profiles with a selection of your boards & check on

Low volume quality PCBs (how to)

Electronics Forum | Fri Jul 15 16:50:04 EDT 2005 | davef

Few of us here on SMTnet fabricate our bare boards. Most of us are assemblers. So, the solderability of the connections of our boards is a BIG issue with us. Our suppliers protect the solderability of the copper by coating the copper to limit the

Very fishy missing solder paste issue

Electronics Forum | Tue Jul 19 05:16:34 EDT 2005 | aj

Hi, I looked at the pictures and it looks as if it should be a straight forward solution..but obviously not. I would focus on the stencil/print more than placement machine. The placement machine simply places the part on the board!#(just one thing

Dek 249 loosing print speed setting after a few passes

Electronics Forum | Thu Jul 21 22:22:50 EDT 2005 | Ken

Hey, Peter. back in the mid 90's I reversed engineered their drive system because of a dispute over print speed malfunctions. I prooved correct that they had made published claims about their drive topology that were not true. They agreed to redes

Selective soldering

Electronics Forum | Wed Jul 27 03:50:51 EDT 2005 | aj

Crishan, I am not familiar with the machine you mentioned. Do you use selective solder pallets through a wave process or is the machine a selective soldering machine (ie. where the board is moved to the solder fountain) No matter what the process

High Temp Reflow Lubricants

Electronics Forum | Wed Aug 03 11:08:24 EDT 2005 | PWH

We use the following stuff from "Biral USA": BIO30 Synthetic High Temp Oil � Chain Oilers NMG-400G � No melt grease - miter gears/lead screws AS500ML � Anti-size spray - lead screws, drive sprockets, rail support L-brackets It seems to work good


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