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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Humidity bake bends leads

Gerry G

#11918

Humidity bake bends leads | 16 April, 1999

While trying to sell me a low temperature baking system for SMDs the salesman mentioned that the 125C for 24hr bake had been known to cause co-planarity defects. I thought I'd ask some experts. Any help guys?

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#11919

Re: Humidity bake bends leads | 16 April, 1999

| While trying to sell me a low temperature baking system for SMDs the salesman mentioned that the 125C for 24hr bake had been known to cause co-planarity defects. | I thought I'd ask some experts. Any help guys? | Gerry: I imagine there could be some combination of conditions where a 125C for 24hr bake can cause co-planarity defects in surface mount devices. But I'm gonna need a couple of six packs to just start hypothesizing in earnest. I keep flashing-on images of a ball-peen hammer. Two things:

1 Call that maroon�s bluff � I mean, GIMMME the proof, show me the study. 2 Baking components degrades the solderability of components and is not good practice. Consider a desiccant cabinet or some packaging approach for your hydroscopic parts.

TTYL

Dave F

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ScottM

#11920

Re: Humidity bake bends leads | 16 April, 1999

| While trying to sell me a low temperature baking system for SMDs the salesman mentioned that the 125C for 24hr bake had been known to cause co-planarity defects. | I thought I'd ask some experts. Any help guys? | Let me get this straight...

He's trying to SELL you an oven, THEN he's telling you his oven will damage the components??????

Whoa! He needs another job.

It's easier not to keep the devices exposed, most packages gives you 168hrs exposure, that's a LOT of time when you re-seal after you pull out what you need. Get a sealer and keep them sealed and keep a log. A nitrogen box is nice but that's a bit more $'s. There are other ideas out on the forum, use them.

Cheers, Scott

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P.L. Sorenson - Technical Consultant

#11921

Re: Humidity bake bends leads | 18 April, 1999

| While trying to sell me a low temperature baking system for SMDs the salesman mentioned that the 125C for 24hr bake had been known to cause co-planarity defects. | I thought I'd ask some experts. Any help guys? | To remove moisture from low quantity critical assemblies a vacuum oven does an excellent job. Temperature and exposure time requirements are reduced substantially.

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#11922

Re: Humidity bake bends leads | 19 April, 1999

| | While trying to sell me a low temperature baking system for SMDs the salesman mentioned that the 125C for 24hr bake had been known to cause co-planarity defects. | | I thought I'd ask some experts. Any help guys? | | | Gerry: I imagine there could be some combination of conditions where a 125C for 24hr bake can cause co-planarity defects in surface mount devices. But I'm gonna need a couple of six packs to just start hypothesizing in earnest. I keep flashing-on images of a ball-peen hammer. Two things: | | 1 Call that maroon�s bluff � I mean, GIMMME the proof, show me the study. | 2 Baking components degrades the solderability of components and is not good practice. Consider a desiccant cabinet or some packaging approach for your hydroscopic parts. | | TTYL | | Dave F | | | I'm with these guys. I've had parts baked, but never saw coplanarity problems come out of the oven that weren't there when they went into the oven. Oh, wait, now I rememeber - there was that time when the whole waffle tray took a spill - does handling count?

I'm not a fan of baking, either. Parts come with enough solderability isses - far be it for me to add to them. Dessicant storage (pkg or cabinet) should do it.

And as for this sales guy - I'd let him buy me a big lunch with a couple of beers, then ask him to "show me da study." |

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