Inspired by luisr320's using his CNC router to make a PCB (see
https://lowpowerlab.com/forum/index.php/topic,943.msg6076.html#msg6076), I decided to give it a try with my home build CNC router that I made primarily for woodworking. Since making my router, I've found more and more interesting applications, including V-grooving panelized PCBs so that I could break them apart easily.
I thought it would be useful for 'quickturn' prototype projects and was not expecting to do any high density PCBs with this device. Still, the resolution of my router is 1mil and the accuracy isn't too far off so I thought it was possible to use it for this application.
Armed with the pcb-gcode.ulp program added to my Eagle setup, I created two simple designs. The first is an LCD breakout board I needed for an LCD display with 1.8mm pitch pins so that I could fan out those pins to a standard 0.100" header. The Eagle design looks like this:
As you can see it's pretty simple, but also very useful.
The next design is a PCB for a Moteino based Electric Power Monitor. This monitors 4 channels of clip-on AC Current probes and reports RMS AmpSeconds every 10 minutes. I only need two or three of them and was originally just going to go the perf-board route, but, again, Luis reminded me that I should give the CNC 'route' a try. Here is the PCB for the Power Monitor:
It is also a simple, one layer design, but I did find that I needed to modify the component library to get this to work on the router.
I was pretty sure from the outset that I would need heavier traces than I would normally use and in this case had selected 50mil traces to start. What I hadn't planned on was that I'd also need bigger pads for all of the components. Part of this was due the fact that I can't drill holes as small as most PCB houses - I might be able to do a couple, but not a boardful without breaking drill bits. So, with the idea that I would have 40 mil holes, I learned that the normal sized pads quickly disappeared after routing.
I also had to make a couple of passes to tweak the parameters for the pcb-gcode.ulp program to get a reliable and good PCB on my router. Fortunately the program is easily modified and, in the end, only took two full passes to get a useful set of boards.
Here are the resulting PCBs:
Being Routed (held down with my vacuum chuck):
Breakout Board:
Power Monitor PCB:
I'll be posting this project with schematics and code separately.
I can provide details on the parameters I used if anyone is interested.
Tom