In order for the ABS plastic to stick well enough to the polyimide film build base it needs to be heated to at least 100°C [212°F]. I purchased an Omega CN7500 temperature controller to provide power to the flexible heaters. One of the really nice things about this controller is that it features auto-tuning PID control so you will get the best temperature control without having to manually set all of your PID constants.
Wiring to the PID Temperature Controller
The blue wires connect to the flexible heaters, four per connector. Then the orange-ish wire is a J type thermocouple connector. I used connectors instead of hard wiring everything to make it easy to remove the build plate if needed.
Testing the Heated Build Base
First tests were successful after the controller ran through a few heating cycles in order to calibrate the PID settings. For the tests I was concerned about the EMI that would be generated from the relays turning on and off in the controller, so I placed it behind a steel block. This EMI could potentially crash the machine micro controller while running code. I had run into this problem on my Fab@Home by placing the temperature controller too close to the micro controller. This time, I made sure to mount the temperature controller out of the way, and I have not had any problems.
Hi Jim. I’m thinking of using the same PID temp controller. Not sure how to hook it up though. It seems you hooked the heating elements directly to the PID? or did you use a relay?
The temperature controller has a relays in it. Basically, the flexible heaters are connected to one side of the heating relay in the controller. The other side of this relay is connected to a regular U.S. power outlet (115 VAC).