Jul 072010
 

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.
http://solsylva.com/cnc/13x13x5.shtml

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.
http://www.kelinginc.net/

Cutting tool is 1/4″ trim router from Harbor Freight and a speed controller.
http://www.harborfreight.com/1-4-quarter-inch-trim-router-44914.html
http://www.harborfreight.com/router-speed-control-43060.html

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.
http://www.machsupport.com/
http://linuxcnc.org/

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.
http://www.cambam.co.uk/
http://www.inkscape.org/
http://www.getpaint.net/

To make sure it was going to run about how I expect it to, I ran it through a free CNC machine simulator.
http://www.cncsimulator.com/

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

Result: