8 April 2014 – When we assemble prototype PCB’s in the lab using SMD components and solder paste, we use a normal desktop oven to reflow the boards. In the beginning we used a TV-braai – well, that’s what we call it in South Africa – and just eye balled it till we guessed it was cooked enough! Surprisingly I have built quite complex PCB’s using this method with a great success rate.
After a while we decided to hack an off-the-shelf oven and add some form of temperature control. We did this by ripping out some of the internals and controlling it with a relay and thermocouple. This has been working perfectly for a few years except for the unsightly project box and wires protruding from the oven. I always wanted to make a dedicated PCB to control the oven and finally made the time to do it. The following was on my wish list:
- Minimal hacking of the oven.
- Safety.
- Hacker friendly (Arduino™).
I decided to us a fused opto-isolated triac circuit capable of driving a 3000W oven. Added a MAX31855 thermocouple-to-digital coverter and added a piezzo buzzer, RGB LED, fan output and a connector with inputs for 3 push buttons. The smallest panel mount connector I could readily and cheaply find was a standard DB connector and used a Degson power connector for the AC line. The idea is to place the oven controller inside a project/laser cut box. Fit a panel mount AC socket to the side of the box where the oven can be plugged in using the plug which it came with. The oven can then be controlled using any micro controller of your choice such as an Arduino™ via the DB connector. The thermocouple can be inserted into the oven via the door or you could drill a hole in the side and mount it properly. I should mention a thermocouple in free air usually reads lower temps than the actual PCB because the PCB absorbs the heat better than the air and you should calibrate for this. Another option is to temporarily fix the thermocouple to your PCB with a paper clip but I find I never have space for this.
Here are some photos of the finalized PCB:
We have extra PCB’s available and will sell them as blanks, populated or in a laser cut enclosure. Give us a shout if you are interested.
Hi. I am interested in your oven controller. Can you supply in kit form (unpopulated) with laser cut enclosure?
Hi,
We do have blank PCB’s available. I will need to check if I have all the components necessary. Expect an email later today.
Hi
Do you still have any of the reflow controller kit or boards
Hi,
Sorry for the delayed reply. Been super busy and neglecting the blog lately…
I do have blank PCB’s you can use to control your oven – only the thermocouple and AC triac side etc. as seen in the post. You will need to use your own controller such as an Arduino or similar for the PWM control and display. I do have enough components to assemble 1 unit – first-come-first-serve I suppose… I can either send you the blank PCB and BOM for you to assemble yourself or I can order the components and assemble it for you. Bit of a chicken and egg situation as the PCB has SMT devices…
Please drop me an email or reply here then I will check pricing.
Hi. I’m nterested in getting a controller. can you give me prices please?
regards
george
Hi,
Please see my reply to Anton
Seriously need a working controller to try reflow soldering. Can you supply please?
Thanks!
Hi,
Please see my reply to Anton
Hi guys,
For those that might still be looking for a reflow controller, I have also designed a unit for this purpose. Drop me an email at nicholas@nsb-electronics.co.za if you would like more details.
Regards,
Nicholas