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Wave solder joint on PTH part

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#46636

Wave solder joint on PTH part | 12 January, 2007

Hello all, We have resently run across a solder joint from a through hole part that looks to have a wrinkle effect (star look) from the wave? No pattern it just happens here and there, and some of the joints on the same row look smooth and good. Any guess?

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John S.

#46638

Wave solder joint on PTH part | 12 January, 2007

I've not seen it on a solder joint, but I've seen it on an SMT pad that had been skipped in a wave solder operation. The boards were under inspection for poor solderability. We never really pinpointed the cause. It would make a perfect 6 pointed star shape of little bumps in the solder at a microscopic level. Can you give any specifics on your process? Flux, preheat type and temp, wave type(s) and temp, debridging knife etc.. John S.

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#46663

Wave solder joint on PTH part | 15 January, 2007

The wave process, Flux (NR 330) 3 zones preheat top and bottom side convection, with solder pot at 260 C. PCB is ran in a selective wave pallet.

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John S.

#46675

Wave solder joint on PTH part | 15 January, 2007

Since it is in a pallet, I would be sure the preheat temperature is correct across the entire assembly. We've seen large temperatue delta's across assemblies that are soldered in pallets. Could be overheated even or contact time too long.

Interestingly enough, the assembly I was working with also used NR 330. Some odd phenomenon of the flux?

John S.

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greg york

#46684

Wave solder joint on PTH part | 15 January, 2007

probably volatiles in the joint outgassing as it comes over the wave, is the joint a yellowy colour as well, or any pictures we can view cheers greg

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#46713

Wave solder joint on PTH part | 16 January, 2007

I think John is right. I've seen the same thing (I think, without a picture who knows)on heavy heatsink parts. But I've also seen this happen on larger parts that move right after being wave soldered. I'm talking within a second or two of being soldered.

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