CNC Thoughts

My first attempt at designing a CNC router failed miserably. Perhaps a version 2 can be built with what I’ve learned. But for now, I bought a set of plans.

I liked the 3 axis kits available from Keling Technology. 425 in-oz stepper motors, C10 breakout board, KL-4030 microstepping driver, and power supplies. Wired up bipolar parallel, initial runs 1/4 stepping at 1.8A. I was occasionally losing steps on the Z axis, so I increased the power to that stepper a bit.

Cutting tool is 1/4″ trim router from Harbor Freight and a speed controller.

Software for driving the steppers… I used a demo of Mach3 at first because it seems to be extremely well supported all over the internets, but $175 seems a bit steep considering EMC2 has many of the same features, a simpler UI, and is completely free. I will have to compare again after I’ve used the machine more.

So how to tell Mach3 or EMC2 what to draw? My first attempt was with cambam. It wasn’t difficult, but could have been easier. I started with a logo, opened it with Paint.NET, converted to greyscale. Then opened it with inkscape, traced the logo and resized and removed parts I didn’t want to engrave. Saved that as a DXF file and opened with cambam. I suspect Inkscape saves DXF files in mm or pica since I had to resize in cambam as well. I removed extra lines, converted arcs to polyline, and joined them to create many fewer lines. I then created an engraving and exported gcode.

To make sure it was going to run about how I expect it to, I ran it through a free CNC machine simulator.

I wouldn’t have been able to figure out things nearly as quickly as I did without the cnczone forums.


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