Electronics Forum | Wed Sep 19 21:04:57 EDT 2007 | wailiang81
Hi,davef, thanks for your concern. The condition was the pasted printed off with around 0.8~0.9mm from the land pattern. This will easy observe at QFP area. At fiducial, the stencil seens aligned accurately. Once solder bridge happend, its easy to
Electronics Forum | Fri Nov 02 09:00:09 EDT 2007 | ck_the_flip
Steve, your best solderer in your shop will know that this ain't standard wire solder. I always put the best solderer on T/C attachment duty when I have a scrap PCB to play with. They even have difficulty getting the stuff to wet to pads and leads.
Electronics Forum | Sun Nov 04 01:04:04 EST 2007 | omidjuve
we are manufacturing some rf boards that works on a high frequency margins now our boards doesn't pass in impedance test and we concluded that the problem might cause by the solder paste that we are using . our solder alloy is sn62/pb36/ag2 and we t
Electronics Forum | Sat Nov 10 23:46:36 EST 2007 | mika
BTW, The surrounded QFN fine pitch terminals should have the normal aperture reduction of 7 % in case of RoHS Senju solder paste. This works for our Telecom customer. The vias in the ground pad will be somewhat filled with solder and makes it diffi
Electronics Forum | Wed Nov 14 01:00:20 EST 2007 | reypal
recently, we also have problem with QFN around 3% defect related to soldering. from the cross section it turns out to be solder crack. it could be the paste volume on the center pad is too much causing QFN to float that eventually will cause crack on
Electronics Forum | Tue Dec 11 10:12:36 EST 2007 | George
Hi everybody, Is there any criteria as far as No-clean flux residues surrounding solder joints when using selective solder machines? I have a Novastar SPA 400 and use flux NC kester 959. If I decrease the amount of flux, then I experience problems w
Electronics Forum | Mon Dec 17 02:08:21 EST 2007 | mun4o
Hi, I have a lot of solder bridge in our wave soldering process.We use SACX0307 and Surf 11 flux.the SW mashine is Vitronics delta 6622.Itry to change flux and termoprofile but results is not god.Can you halp me - recommend me some flux or other adv
Electronics Forum | Wed Jan 09 13:03:22 EST 2008 | patrickbruneel
Matte solder mask greatly reduces the potential for solder balls, and since you altered the machine parameters with no improvement it might be flux related. Do you use a VOC free (water based) or alcohol based no-clean flux? Do you use machine settin
Electronics Forum | Wed Jan 09 13:39:48 EST 2008 | ck_the_flip
Mask finish is the #1 variable for micro-balling with wave and selective processes. The #2 variable is the Flux. There are some flux formulations out there who're known to have additives that virtually eliminate micro-balling. However, keep in min
Electronics Forum | Tue Jan 15 13:16:25 EST 2008 | ck_the_flip
Yes, the previous "non-balling" flux was alcohol based, but very weak activity. We found it was worth the switch to water-based, to get prettier solder joints - but...at the expense of having to "brush off" solder balls on a couple of assemblies wit
