Electronics Forum | Tue Mar 13 18:52:21 EST 2001 | jax
Are the boards in question immersion gold? This could be a process problem at the board shop. If this subcontractor has done good work for you in the past it might be an outside variable causing the problem.
Electronics Forum | Wed Mar 14 10:02:36 EST 2001 | blair
Boards were not immersion gold. They were HASL but I would like to change. What is the prefered surface fininsh for BGA and fine pitch stuff these days? I am starting to ask for Gold/Nickel on FAB Dwgs due to PCB house and assy house discussions.
Electronics Forum | Wed Mar 14 17:26:03 EST 2001 | davef
Most $$-value stuff is dependant on the cost structure of the company. Why not do a small cost study to measure the amount of time your improvements save? Folk in accounting should be able to "rough price" the $$ benefit of your efforts.
Electronics Forum | Thu Mar 15 11:12:45 EST 2001 | slthomas
solder, but flux -> adhesive. Hmmmmm.... Are the chemists working hard to reduce the consequences of these possibilities? And as to Dave's comment about long term reliability issues due to outgassing from the adhesive, double-hmmmmmmm....... Ther
Electronics Forum | Thu Mar 15 11:18:12 EST 2001 | slthomas
That makes us almost even, Dave. I have a hard time believing half of what you say. ;)
Electronics Forum | Thu Mar 15 21:02:20 EST 2001 | davef
Wazis havin' "a hard time believing half of what you say"? I demand a least 90% from peeps!!!
Electronics Forum | Fri Mar 16 13:50:16 EST 2001 | mparker
Shadowing sounds about right to me also. Really dicey experiment to run if you are dropping expensive tantalums just to save a little coin in epoxy and processing time.
Electronics Forum | Fri Mar 16 15:52:22 EST 2001 | blnorman
We screen print epoxy adhesive, place components then run the board through our adhesive oven (2-5 min cure at 150�C). This is in addition to reflow.
Electronics Forum | Fri Mar 16 16:33:45 EST 2001 | davef
That's what we do also. It's the "print, dispense" sequence that's peculiar, but that's what you need to do if you are going to eliminate the glue cure cycle.
Electronics Forum | Wed Mar 14 08:45:41 EST 2001 | stefwitt
In order to track the board flow through your line you will have to hook up all conveyor input sensors as well as the last output sensor to a PLC. You can program the PLC to provide an alarm signal if a accumulative time of xxx hours for any board is
