More information on the (ongoing) saga of my recent purchase…

Using a multimeter it was easy to work out the wires coming from each motor. They are bipolar and so two pairs of the four wires will register a resistance, these are the A and B coils. They require 24V and 0.5 Amps. They stay cool during a run and I haven’t had any issues yet. Within Mach3 Motor Tuning I set them to 1016 steps per inch, 120 i.p.m. and an acceleration of 4. This seems to work OK.

After getting the gantry under control, all that remained was turning the laser on and off. Luckily Andy Slater had already solved this problem, by identifying an external control line on the laser power board.

I hooked up the two extra wires describe in Andy’s article, and connected them to Gnd and Pin 8 on my parallel breakout board. Inside Mach3 I was able to configure output #1 to use pin 8 and therefore get the spindle commands M11P1 (On) and M5 (Off) to control the beam. Important note – by default the pin is High when the computer starts, only being pulled low when Mach3 starts up, therefore it’s important to disable the laser until you are ready to start cutting, either by opening the lid of the machine, or using the “Laser Enable” switch.

So now on to create some laser-ready G-Code. All my existing work had been milling with a spindle – here the spindle was just turned on and off by hand and the Z depth denoted how much cutting was applied to the billet. I decided to create the G-Code for a standard milling operation and then replace the Z plunge/retract movements with the laser on/off commands.

I set the tool to be 1mm wide, with a max depth of 2mm. The safe Z was set at +10mm. I then set the plunge depth at 1mm (ensuring only a single pass would be generated) and create the G-Code file. In a text editor it was simple matter to replace all the calls to set the Z depth to -1mm with M11P1, and all calls of Z 10mm to M5. This strategy worked rather well.

BTW : Here is a neat online G-Code commenter – plug in some G-Code on the left, and get an explanation on the right.

This video shows one of my first few cuts – I forgot to remove the initial M6 from the file, hence the laser starting up even before moving into position.

Acrylic cuts really well, however I think it would benefit from an “air assist” upgrade – I think I’ll try adding that next. It’s my goal to be able to cut quarter inch acrylic cleanly – then I can make *stuff*.

I seriously doubt that I would be able to make the above figure using my CNC mill.

The vendor has offered a free replacement controller board (or a refund on just the board) – I was tempted to go for the refund, but I’m thinking now that I should give him a chance to replace it, and see how I get on with the “NewlyDraw” package that came with the cutter.