DIY UV Curing Chamber Pt. 5
Alright! This thing is finally starting to look like something.
Last time I had finished printing the main components for the turntable. From that point I installed the bearings and assembled the components. I installed the motor with a couple of small M3 machine screws, then soldered wires onto the motor’s lead. Finally I covered the joints with shrink wrap and fed the wires down through the hole in the main body. At this point I realized that I could have cleaned up the wire routing by placing the hole to the rear of the motor. Mildly unfortunate perhaps, but I’m not concerned with it. Sometimes it’s important to get on with a project, rather than fuss over minute details.
The next step was to get this puppy turning. At first I plugged leads directly into a 6v DC power supply, but as it turns out, the motor spun too fast. Can’t be slingin’ parts about inside the curing chamber now, can we? As luck would have it, I have a small DC motor speed controller from a previous project of mine, so I plugged that into the circuit. While I’m not particularly clear on how the speed controller does its job, the practical effect is that the output voltage is lowered. It seems that the motor I’m using has a start voltage of about 1V, so I tuned the speed controller to 1.2V to ensure the motor will start every time.
At this point in my testing I was using a rubber band as the drive belt. This worked OK for testing, but the high elasticity of the band caused it to go taught on one side of the pulley and slack on the other side. This imbalance ultimately caused the band to walk off of the pulleys. To fix that issue I printed a drive belt with NinjaFlex filament (which is much less elastic than a rubber band). So far that’s working great!
Next came the matter of integrating the turntable into the rest of the system. I originally set out to create a curing chamber that would run automatically. From a UX perspective, my ideal device would allow me to place my freshly printed parts on the turntable, close the box, and hit a button. The chamber would then run through a cycle of say, 20 minutes, then shut itself off. This way I don’t run the risk of forgetting to turn off the lamp and over-curing parts.
I happened to find a 2-outlet digital wall timer that has a countdown feature. And while it’s not quite one-button operation, it’s good enough for an out-of-the-box product. I plugged the UV lamp into one side, the turntable into the other and set the countdown for 20 minutes. Great success! So for all intents and purposes, the electronics are done! All I need to do is build the chamber itself and set up the controls up in a useful manner and I think I’ll be able to call this project complete!