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Batch oven

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#53419

Batch oven | 29 January, 2008

Looking for recommendations on a small bench-top batch oven for reflowing simple one sided boards. Does anyone have any experience or recommendations? I'd consider used over the Asian imports to save money,... as long as it's the right oven .

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#53430

Batch oven | 29 January, 2008

Well, I don't know if you want to muck around this much, but I bought a GE (Chinese made, of course) toaster oven with convection fan. Nice big glass door in front, you can use it in bake, broil, toast or convection oven mode. The only thing missing is a precise thermostat. So, I got a thermocouple ramp and soak controller on eBay, but you can get these for a few hundred $ from Omega. I added a solid state relay and patched it in in place of the oven't thermostat.

After running a few boards with it, I found I got the best results by actually poking the thermocouple junction into a through-hole in the board. Thus, the controller is actually controlling the temperature of the board itself, not the air in the oven. This has worked remarkably well for me. I do some larger boards as well as 4 or 6 smaller ones at a time.

Jon

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#53527

Batch oven | 1 February, 2008

Thanks John, You built smart batch I/R oven from a consumer toaster oven and that sounds pretty cool and cheap too. I'm hoping that we don't have to resort to all of that to get what we need... although I have been toying around with the idea of building a batch vapor phase reflow system myself. Talk about over priced reflow systems!

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#53528

Batch oven | 1 February, 2008

I looked at a number of small bench-top batch ovens and saw two things. First, they got VERY expensive when you got above the very smallest units. Mine will fit an 8 x 12" board. I still have to do one that size and see how uniform the temperature is. But, I have done several smaller boards that filled the entire space, and they came out pretty good. I have one corner by the vent that runs a little cooler, and I'm thinking I have to seal up the vent to improve uniformity.

The other thing I notices was very long cycle times. Since I am actually running this contraption in production, I wanted to avoid that. I can open the front of the oven when it cools to about 100 C and swap the next batch in. Even with all my fooling around, I can do a batch about every 10 minutes.

Jon

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