Electronics Forum | Thu Jan 03 08:02:53 EST 2002 | davef
Slump is a function of the particular paste you select and the temperature of the paste. Use a slump test like the one that follows to compare fluxes. Slump Test Step Process activity 1 Print paste on white ceramic substrate or microscope sli
Electronics Forum | Thu Jul 07 18:07:38 EDT 2005 | saragorcos
Ahh. sorry for the foul up - and thanks for stopping the spread of misinformation!! Sarag
Electronics Forum | Tue Nov 04 07:50:14 EST 2008 | davef
Sure. Here's what you should do to apply repeatable amounts of flux on BGA during rework: * Squirt some gel flux on a plate or something like that that has a flat bottom and raised sides to corral the flux. * Cut notches into one edge of an old credi
Electronics Forum | Mon Nov 12 18:08:37 EST 2007 | samir
That's when you give that "Supervisor" a tall glass of SHUT THE F*CK UP. I betcha you regret even mentioning it to him. I'd have just made up some techno-babble and switched it regardless. Told him something like - "pure IPA will act as a catlyst
Electronics Forum | Fri Jan 28 12:29:01 EST 2005 | Bob R.
We use the exact same method Chunks outlined for evaluating just about anything we're going to roll out worldwide, whether it's a material or a machine. List your factors (print speed, solder spread, etc), assign each a weight, evaluate each paste a
Electronics Forum | Fri Jan 28 12:18:32 EST 2005 | Chunks
Your best bet is to do a decision making matrix. Each company has so many different criteria�s it's hard to pick out which one might be important to yours. Simply pick out your top 5 paste manufactures. Next decide what your "Eliminators" are - th
Electronics Forum | Tue Mar 15 22:04:56 EST 2005 | KEN
The hasl joint looks fuller (and is easier to inspect)because it has more solder volume. Think about it. Your pre-plating your board with solder (before you add more solder). I doubt your getting 0.3 mils of hasl.....probably more like 1.3 to 3.0
Electronics Forum | Tue Sep 25 15:48:34 EDT 2001 | mparker
Scavenge all the old solder off the board and the chip. Micro screen paste to the chip. As far as thickness, check your aspect ratio to determine the spec. Eliminate just one variable at a time to get to the root cause. Start by not using the tacky
Electronics Forum | Fri Jul 10 13:55:16 EDT 1998 | Bob Willis
After reflow the paste on a copper pad should spread out from its original print dimensions it should ideally not prior to reflow as that is a hot slump. The better the solderability of the OSP or the higher the activity of the flux will greter flow
Electronics Forum | Fri Jan 24 16:54:24 EST 2014 | davef
Yeh, I worked at Wang Computer factory in a reclaimed fabric mill with wooden floors. One of the causes of grapping is flux loss. In their paper, Briggs and Laskey talk about flux loss due to spreading and suggest: * Graping is much less prevalent i
