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Reflow problem

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#67363

Reflow problem | 26 September, 2012

We have been having a solder paste reflow issue which results in the solder not wetting to the LED lead. The solder appears to create "puddles" on the pcb pad. I have attached AOI image for review. We have had the pads analyzed for contamination, which showed nothing abnormal. We have reviewed our reflow profile. Solder Paste- AIM NC257-2 ProFlow.

Any ideas of the cause of this would be greatly appreciated.

Thanks in Advance Gary M

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#67369

Reflow problem | 26 September, 2012

Pads look WAY oversize for the LED leads. Perhaps the solder won't go to the LED because it is spreading across the pads on the PCB instead. The board pad vs. component lead size equation I see would make me expect some starvation of the joints at the LED, and this result doesn't necessarily surprise me. I would like to see those PCB pads reduced by about 50-75% in size/area in an effort to help eliminate the problem.

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#67370

Reflow problem | 26 September, 2012

*Like*

I totally concur.

And props on the photoshopped process improvement. I tip my cap to you sir.

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#67371

Reflow problem | 26 September, 2012

Per the pictures you sent it may be a Pad Design issue, you need to go to the Part Number Spec and Look for Suggested Pad Layout

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#67372

Reflow problem | 26 September, 2012

Thanks for the input everyone. We had also suspected pad design, but wanted to get input from other sources. The design engineer has implemented revised pad design in a revision set for production next week.

Thanks again,

Gary M

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reflow oven profiler

Reflow Oven