Laser Cutter

[ABearden]

Another few hours of testing in. Cut up the old shroud to experiment a little bit. Trimmed it down to just the lens enclosure and tapped a hole for a 1/4" NPT quick-connect fitting. Unfortunately my 1.5 gallon air compressor doesn't do very well keeping up so I re-piped a few things to piggyback a reservoir. It helps buffer the demand a little bit, but long term I'm going to need more reservoir.

Once I finished with the air testing, I started on the last bit I needed: the trigger. First thing required was an update from GRBL 0.8 to 0.9. They swapped some pins around so the spindle enable pin could be utilized as a spindle speed control. I loaded the sketch, edited a few settings, then uploaded it. And nothing. Nothing at all. No response to commands, no stepper pulses for movement, nada. Did a lot of searching and eventually found a forum reply with info not mentioned in the GRBL documentation: the default baud rate changed from 9600 to 115k with version 0.9. Hmm, might be important to know. Unfortunately that takes my favorite software out of the mix for now (it's written specifically for GRBL 0.8, thus 9600 baud only).

With that situated, I moved to the hardware. I read somewhere it's bad to turn the tube on and off quickly with PWM, but I can't find that source now and everything else I read says that PWM is just fine. But because I don't trust the Chinese power supply and the stock setup runs analog, I popped a simple RC circuit made of a 510 ohm resistor and 4.7 uF capacitor onto the pin output to change the signal from a square wave to DC with a little ripple just to be safe. Verified with an oscilloscope (man, haven't used one of those in a while).

Hopefully, I'll get a chance in the next day or two to hook it all together into a seamless system.