Electronics Forum | Wed Jan 14 06:42:38 EST 2004 | tommy
We see spattered(spitting of flux or solder to nearby area) solder/flux on gold fingers.We view the gold fingers area under 30x before reflow and it is cleaned but after reflow we see flux droplets or solder on gold fingers. We tried to changed a new
Electronics Forum | Wed Jan 14 08:28:46 EST 2004 | davef
Search the fine SMTnet Archives for background on solder on gold fingers. As we recall: * Paste selection * Proper reflow recipe tuning ... are important.
Electronics Forum | Tue Jun 05 22:18:47 EDT 2001 | Dreamsniper
I don't understand why you wanna do this. The vendor has done this part for you and actually they have a recommended glue / solder paste life on the stencil or pcb (e.g. 6 hrs, 8 hrs.). If you will stick with their recommendations you won't be lost p
Electronics Forum | Fri May 25 17:25:25 EDT 2001 | morefun
Is anyone out there is the contract or the OEM sections using viscometers to check solder paste or glue for acurate process definitions. By this I mean check the materials viscosity over a period of time and measure the degradation of performance, t
Electronics Forum | Tue Jan 31 09:41:06 EST 2017 | emeto
If there is no specific quality reason, stay with paste. More processes you add, more points of failure. They don't need a lot of paste to get attached to the board. The ones I used were 8mil round apertures, so I did cut 1:1 on a 3 mil coated stenci
Electronics Forum | Mon Feb 13 01:47:28 EST 2017 | soldertraining
Solder flux and solder paste deposition is a standard step during the chip attach and sphere attach portions of BGA and CSP assembly. A technique called ultra-violet fluorescence intensity mapping (UV FIM) has been introduced that allows flux measure
Electronics Forum | Wed Feb 01 11:33:37 EST 2017 | emeto
Joshua, 100um is 4mil aperture. You should ask several stencil houses about the possibility to print that small amount of paste(type 6 paste is available now with very small solder spheres 5-15um diameter). Even applying small amount(thin layer of f
Electronics Forum | Wed Feb 01 03:17:10 EST 2017 | rob
Ok, that's small - I think you may need a special semi-conductor printer for this - positional accuracy on a "normal" SMT printer is no more than 20 micrometres from memory. In my semiconductror fab days we were printing with a positional accuracy
Electronics Forum | Wed Nov 01 18:20:21 EST 2006 | russ
Flux is fine, make sure you have one that will withstand the extended and hotter reflow for the Lead free, your paste MFGR will most likely have the flux formula in their paste available as a tacky or paste flux Russ
Electronics Forum | Tue Oct 31 21:26:40 EST 2006 | davef
We've always used flux in reworking BGA, except with some dodgy designs, when we use paste. We see no reason to switch to paste. We do not understand your coworker's concerns, nor do we understand the impact of using paste because of the higher mel
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