How do you re-bake your SMD components?

[Nick C.]

As a hobbyist, I'm wondering what my options are for re-baking SMD parts (to drive out moisture) prior to reflow soldering.

I'm tempted to just get a cheap toaster oven and bake the parts for 24 hours at 125 degrees celcius, per IPC/JEDEC J-STD-033.

Is there a better way, keeping in mind that I'm a hobbyist and can't justify spending $5000+ for a proper 'dry box'.

Thanks!

 

[enjunear]

I've never looked into the option for home-rigs, but it seems like it'd have merit.

The first concern I'd have about using a toaster oven is that some areas of your board may get hotter than 125C, due to non-uniform distribution of the heating elements. If you do go the toaster route, I'd run at something less than 125C to ensure adequate margin for hot spots, and not overheating some components to the point of causing degradation/failure. Maybe run 100C, and extend the time?

 

[keith1200rs]

Dan Strother's site has some information about building you own reflow oven which may be useful danstrother.com | robots, fpgas, tesla coils, photography, etcetera

Keith

 

[Nick C.]

Thanks for the replies, guys. I don't think I was as clear as I could have been.
The actual soldering I have under control, but I'm looking for a way to 'bake' the
parts _before_ soldering them, to drive out the moisture that's absorbed by the
components as they sit in storage (sometimes for years).

Using a toaster oven will work, but it seems so very wasteful to run something like
that for a whole day just to dry a part or two.

This is a long-shot, but I wonder if anyone has experimented with a homemade
version of a "dry gas blanket" - displacing the moisture-filled air in a container of
baked parts with an inert gas. This works very well for keeping moisture-sensitive
glues from going bad. I've been re-vacuum sealing bags every time I take a part
out, adding fresh dessicant packets each time, but this gets old fast.

Then again, maybe this isn't as much of a problem as I think it is. Lots of people are
soldering SMD parts at home, and I rarely read about people 'pre-baking' their parts.

Still, I wouldn't think that component manufacturers would require such handling if it
wasn't necessary.

:-?:-?:-?

 

[enjunear]

To get the maximum longevity and performance out of your parts, you want to control their environment (this is generally done by conformal coating the assembled PCB). If you look into the vendors' specs, you can find information about the environmental ranges, but it's typically pretty arduous.

I don't go to any great lengths with SMD parts that are used in my home projects, or the parts in my stash of extra piece-parts in the lab at work. They generally live in little paper envelopes (R's, C's and L's)... semiconductors go in anti-static bags; none get special treatment for humidity. I have yet to run into an issue.

Your mileage may vary. :wink: