Heat Treatment Oven

Question

Hi All

I wish to build a heat treatment oven/forge. The main use for it would be heat treatment of wood working tools but i would also like to be able to use it to make Mokume-gane so i need it to be fully electrical so i can flood the heating chamber with inert gases such as argon or co2/argon mix. I would like to be able to make the elements and gases flow rate fully programmable. Which would be better for use raspberry pi or aurdino

D_Hersey · Accepted Answer

Except in really special applications, I recommend getting a high-quality temperature controller from (off of?) EBAY. Use one with an external SSR, so you can scale to your load. Thermocouples aren't really a good place for noobs, my opinion, nor is PID. Similarly, I'd buy a furnace and modify it rather than scratch build, probably. The item you need to switch your gas on is called a solenoid-operated valve. These will be relatively small, so they 'desire' a hard-landing. Very large valves sometimes need a soft-landing, a discussion probably outside of our scope here. You need to shunt your solenoids with a reversed diode. The current rating (plus design margin) of the diode is that of your solenoid. The point of this is to deal with the EMF created by the collapsing magnetic field of the solenoid. You want to place this and a capacitor (in shunt w/ load) with about an (decimal) order-of-magnitude of energy storage relative to the solenoid inductance proximately as possible to the device they protect. The diode should be fast. The capacitor should be low-ESR. Over-rate your drive Qs and isolate them from your logic supply.

waelect · Answer

There would not be enough infomration in your question. One factor to consider is the resulution of your sampling, this may require 8, 16 or 32 bit processing. In this case only a limited number of Arduino dedicated Emmbedded processors maybe required. Will you use sensor that operate under Linux or via I2C or Network based, as these are about the only way you can you can use Raspberry Pi.

waelect · Answer

I would have to agree about buying the ready made kiln and then alter it. I think this project is not soley for noobs, You are dealing with not only making high but also designing it. If I was going to make this project I would use something different to a arduino but it would. A Raspberry Pi wouldn't cut it as you require analog sensing which Raspberry Pi does not have. In designing you will need to source what sensing component you are going to use to sense the temperature, the Gas Flow. Forom there consider which development board to use.