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Old 04-29-2013, 06:54 AM   #1
a_double

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Default heat contoller

Hi guys i want to buld a curing oven and i need a contoller to contol the temp, any idea where i can get a contoller @ reasonable price . please share pictures of your oven and controller.

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Old 05-03-2013, 03:48 AM   #2
herman

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I think Susho already has done a lot of work on oven controller design. Perhaps he can share his ideas.
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Old 05-03-2013, 01:26 PM   #3
em02057

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Quote:
Originally Posted by a_double View Post
Hi guys i want to buld a curing oven and i need a contoller to contol the temp, any idea where i can get a contoller @ reasonable price . please share pictures of your oven and controller.

Thanks.
A while back I was thinking of building an oven as well ( Still am but waiting for funds so any info on oven building would be greatly appreciated)

For temp controllers I searched ebay and found a lot of digital controllers at reasonable price. Try searching for "PID digital temperature controller"

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Old 05-03-2013, 03:35 PM   #4
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I suppose you need a bunch of temperature controller in a large oven to control that the heated air warms uniformly. maybe placing feelers in the corners where no continuing airstream flows.
I still havent found cheap air fans/ oven fans that resist slighlt over 120c.
Havent decided on the insulating box building material. maybe homebuilding plaster walls but very heavy dusty and heavy and they break easily when disasembelded.
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Old 05-03-2013, 11:05 PM   #5
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Use these sandwich panels:

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Old 05-04-2013, 01:34 AM   #6
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good idea, thanks
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Old 05-06-2013, 07:56 AM   #7
datas_br

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I've just put my oven into service. Basically I took an over-sized kitchen oven and extended the oven cavity. It already had a convection fan built in. I added a PID controller from ebay, which works great. It keeps the temp within 1C - verified with a temp-logger. The only down side to these is that you have very little control over ramp-up and none for cool-down rate.

To extend the cavity I used sheet metal (because I had it laying around) and Rockwool. I have the original door but I still need to make hinges for it. For now I just close the front with rockwool.

The good thing about this set-up is that I have a double failsafe to prevent overcooking the part. The original thermostat is still in service and is set just above the desired temp so if the PID should short I won't burn the part. The oven has a time so I can preset dwell time.
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Old 05-06-2013, 08:08 AM   #8
herman

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I would really love to see a decent ramp up and down computer on it.
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Old 05-06-2013, 10:35 AM   #9
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PID controller with ramp/soak functions. But you would have match the heating unit to your oven, so it can keep up with the controller, and not overshoot too much. Airflow inside the oven off-course is important, not crating heat and cold pockets. Temperature sensors on your mould surface/part provide better information than air temperature.

The cool down part is a lot harder in air heated ovens. I did work with one which had openings at the top opened by the controller. Mostly just fully opened, hardly cooling hard enough. I suspect it to be much more usable with directly heated moulds with liquids.
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Old 05-07-2013, 08:36 AM   #10
datas_br

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Quote:
Originally Posted by herman View Post
I would really love to see a decent ramp up and down computer on it.
I would love to be able to find one that doesn't cost more than the entire oven.
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