PID Controlled Ovens 

I undertook the complete overhaul of two donated, inoperable ovens with scrapped hardware and stripped electronics. Restoring these units was critical to our manufacturing capabilities, as we needed to drastically reduce propellant curing times and achieve the required glass transition temperatures for our high performance, high temperature epoxies.

The process began with a complete teardown, removing all controllers, heating elements, and wiring, as the original systems were outdated and lacked essential safety features. The new design prioritized safety, preheating efficiency, and ease of operation. I implemented new PID controllers in conjunction with a solid state relay to precisely regulate the fans and heating elements. I completely rewired both units, installed new switches, and created detailed wiring schematics that were taped to the side for future iterations and troubleshooting.

The smaller yet more complex unit, our propellant oven, was considered unsatisfactory because the heating element was located on the floor with vent holes, which caused the base to reach extreme temperatures. As a result, the retrofit was more extensive. The heating element was removed from the bottom and relocated to the top with a metal guard installed for protection. To increase circulation throughout the oven, a cylindrical fan originally designed for gas fireplaces was integrated with a ducting system.

For safety, since propellant was being cured, thermal fuses were installed in case the PID controller failed and the heating elements remained on. A cork lining was also installed along all interior surfaces in the event that the underlying metal reached unsafe temperatures.

This redesign allowed six 4 inch propellant grains to cure in the oven simultaneously, drastically reducing curing time and increasing manufacturability within our lab.