Electronics Forum | Wed Apr 22 20:55:04 EDT 2020 | SMTA-Samy
The ideal cooling zone curve should be a mirror image of the reflow zone curve. The more closely this curve mimics the reverse of the reflow curve, the tighter the grain structure of the solder joint will be upon reaching its solid state, yielding a
Electronics Forum | Tue Feb 11 13:22:22 EST 2020 | rgduval
Sebas, I suspect that your finding of needing the fillet for the card to work is a false finding. One that I dealt with for many years in assembly. As a bottom terminated device, a fillet to the side terminals of the device is not required. Adequ
Electronics Forum | Tue Mar 03 07:47:48 EST 2020 | dontfeedphils
Thanks for the info. In a past life I ran everything WS and washed in a batch wash using saponifier. I'm surprised I never saw anything then as we would regularly wash boards assembled on only one side. Unless it's specifically washing in DI only.
Electronics Forum | Fri Mar 20 13:00:14 EDT 2020 | dwl
I've done over printing for Pin in Past applications and you'd be surprised how much you can over print and still end up with an acceptable solder joint and no solder balls. As others pointed out, there are a lot of variables involved, so trial and
Electronics Forum | Tue Jun 23 05:52:15 EDT 2020 | ameenullakhan
Hi dave, Thanks for the input. your valuable feedback always help. which method is better Spindle or T-bar. IPC TM 650 have are considered as standard methods. 1. T bar 2. Spindle. since we have never used it. we are bit confused. Which would be
Electronics Forum | Wed Jun 17 14:29:06 EDT 2020 | emeto
These are great pictures. I have never seen this kind of solder repelling from the pad. My number one suspect now is the PCB. Your focus should be on board plating and contamination. The easiest test is to have meaningful batches from another board h
Electronics Forum | Wed Jul 08 16:28:25 EDT 2020 | duchoang
OSP board finish is the issue. With OSP microBGA board, we need to have enough paste (enough flux) on pads (small pads on BGA), also we need to have strong, more activate flux to get rid of Preservative layer on top of pads. In this case, the OSP did
Electronics Forum | Fri Jun 26 14:27:51 EDT 2020 | victorzubashev
Hi Indhu, It could be multiple reasons but probably one root cause. metal nut might require reflow profile change- you need to check it with SMT reflow profiler. the part might be oxidized - you can check solderability or try to solder part using a
Electronics Forum | Mon Aug 10 12:58:04 EDT 2020 | SMTA-64386637
We have found Acrylic CC under QFNs is a failure mechanism in thermal cycling. The coating acts as a wedge and causes solder joint cracks. We do not coat QFNs. To enhance reliability we have the vias plugged with solder mask. This eliminates some
Electronics Forum | Thu Aug 20 07:11:25 EDT 2020 | sssamw
What your said looks like a acrylic coating thermal expansion causes small solder joint crack. Do you cure coating with heating, or heating after curing? Solder joint crack while you see resistor and QFN trouble? Clear and detail description of your
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