Electronics Forum | Thu Jun 04 02:16:43 EDT 2020 | SMTA-Robert
Looking for CTE and young's modulus values for aluminum backed PCB for solder joint predictions. The data sheets are a bit sparse, and the weighted average method somehow doesn't feel appropriate. Any advice is welcome. Thanks!
Electronics Forum | Mon Jun 22 15:53:35 EDT 2020 | cyber_wolf
This would be a highly unusual "requirement." In house checks on paste viscosity went the way of the buffalo years ago. The question to your customer should be: why ? All of the mainstream paste suppliers should be able to supply you with a COC th
Electronics Forum | Mon Jun 15 20:37:29 EDT 2020 | travishemen
Try sending your boards to rework before SMT and have them remove the excess solder from the fiducials. It usually works great until someone accidentally removes the entire fiducial.
Electronics Forum | Tue Jun 16 14:35:13 EDT 2020 | dwl
for the fiducials, try a donut shape instead of a disc. The HASL solder seems to settle more evenly on a donut than it does on a dic.
Electronics Forum | Tue Jun 16 17:51:49 EDT 2020 | emeto
Your statement is interesting, but not necessarily correct. Are shorts in the same location? Is it one short or multiple? Are there any vias in the BGA pads on the PCB? Is part MSD and handled as ESD?
Electronics Forum | Wed Jun 17 15:20:18 EDT 2020 | rsatmech
Thank you for your valuable inputs. Current two SMT line is running and I have initiated to use two different pcb suppliers in each line. Do I need to check the plating details in issue pcba or random pcb. Kindly suggest.
Electronics Forum | Thu Jun 18 12:43:45 EDT 2020 | emeto
I would say you check FAB drawing and see if there is any strange value on the stackup. Usually board house should inform you of these.
Electronics Forum | Fri Jun 19 03:17:45 EDT 2020 | rsatmech
We also don't inspect any things in incoming PCBs. We have CMM but will be used when we see any abnormality. Kindly advise me on this.
Electronics Forum | Tue Jun 30 09:59:44 EDT 2020 | cph4w
Hi SRINI, Are you able to show X-ray of these 2 locations from other board w/o bridging? Void looks almost perfect circle which I never encountered before.
Electronics Forum | Tue Jun 30 10:25:37 EDT 2020 | rsatmech
Hi CPH, Thanks for your response. Sure I will share. But give me some time since we stopped SMT as of now. I will share you on 7/07/2020
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