Electronics Forum | Wed Aug 21 20:11:34 EDT 2002 | mitch
We are going to begin using a 64 pin 10mm QFP with 0.5mm lead pitch. I was recently asked if we need to purchase our PCB with E3 coating instead of tinned pads when using the .5 pitch. The concept being suggested is that the E3 coating will give us b
Electronics Forum | Tue Nov 05 18:17:00 EST 2002 | russ
This sounds like a contamination issue with the HASL finish.(solder on lead but not on pad). I have experienced this before and it was related to the HASL process at our supplier. They found some type of contaminate in the bath (unfortunately I can
Electronics Forum | Wed Nov 06 20:18:30 EST 2002 | davef
cvrgrrrl Your first thermal cycle with imm silver should be the easiest to solder. That you see copper indicates you did no soldering, got no wetting, produced no intermetallics, etc. Tell us again which components did not solder? Wuzzis "plug" t
Electronics Forum | Wed Nov 06 16:31:59 EST 2002 | slthomas
I would also consider paste control (don't take it personally...I always have to get after people about this one), time on the stencil, time between print and reflow, solderability of the component leads, paste volume (that one really got us once....
Electronics Forum | Thu Nov 14 10:03:40 EST 2002 | davef
Doug, Ooooooooo. You're correct Vinny has to be talking about Rogers teflon boards. Vinny, There are many different types of PTFE based products. Generally speaking, PTFE has a melting point of 620degF and withstands solder reflow and HASL proce
Electronics Forum | Wed Dec 18 15:38:59 EST 2002 | swagner
I have had a similar problem in the past, since I have never worked with a semiautomatic printer there could be a few things I recommend that will not work for you. 1. Make absolutly sure that you have proper support under all of the BGA's. 2. Print
Electronics Forum | Thu Jan 09 10:47:36 EST 2003 | Hussman
Depends on what you mean by shifting towards each other. Otherwise, 7 mil should be fine for 0603. I've used 6mil, 7mil and 8 mil without problems. Generally, stencil thickness won't have a bearing on "shifting" parts. Check placement. Make su
Electronics Forum | Fri Jan 17 04:07:12 EST 2003 | iman
A) Paste Printer : A1) identify the critical SMDs' pads. (choice should go to the BGA, CSP, MLF types...RES,CAP last in line...) A2) get a Paste measurement machine that measures readings of paste height (or better - volume) you are paste printing
Electronics Forum | Mon Jan 13 06:28:15 EST 2003 | johnw
Hi folk's, I'm looking for some help full suggestions here... I've got a ceramic BGA with tn/lead / bismuth balls on it that is over collapsing due to the weight of the momponnet vs the ablity of theball to suppot them. We've spok eto the component
Electronics Forum | Mon Jan 13 16:24:15 EST 2003 | russ
Youch! I know this is going to sound stupid but.... I have done it in the past in limited quantities. We placed capton (polyimide) tape at each of the four corners for a similar situation. It did work but the operator has to be careful in placing
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