So one of the bigger challenges I have had thus far with my CNC router is accurately setting the z distance from the work surface.  I saw a link on the interweb describing a method of using a "touch-off pad" to make the process easier.  I set out last night to build one, and it was a great success.  You can see the image of the completed pad below, as well as a really bad video of the machine cutting it out.

I purchased an ENC28J60 Ethernet module to interface with the digital sensor system we are building.  I tried to integrate it into the existing system but things did not work.  I stripped the circuit down to the bare minimum and after some modifications to the wiring scheme and changes to the firmware IP stack, the module came up and worked.   It is now responding properly to pings, displaying a web page, and handling basic remote requests properly.   I know it is boring but attached is a video of the port at work (blinking activity light.)

Link light on ENC28J60 finally working with Arduino from Ira Burton on Vimeo.

I decided that one of the first upgrades to my DIY CNC machine would be to add a see through router platform so that I could watch the machine cut a little easier.  I designed up a replacement platform in CAM BAM, set the machining operations and sent the G-Code to the mill.  In about an hour I had a nice platform and some knowledge on milling a new material.  I elected to build the platfrom from a piece of 3/4" clear acrylic that I got from a local vendor's scrap bin.

While working the acrylic I found that I got better results when the router was running at 18-20k RPM with light passes.  If I cut to aggressively or with a high RPM the plastic would melt and make a mess, so I was fairly passive in my approach and the results were great.  I did a light sanding pass on the cut edges with 400 grit paper then flame polished the edges.  I am guessing the big issue with this platform will be the buildup of fine sawdust on the surface which I hope some good dust collection will help with.

Clear DIY CNC Router Platform from Ira Burton on Vimeo.

If you would like to view the support files (CamBam, DXF, G-Code), you can download them [here].

The CNC machine cut it's first complete part last night.  I designed the gear in Cam Bam, exported the g-code, loaded it EMC2, and it just ran, it was very exciting.  The part is a bout 8" in diameter and took 2 hours to cut.  It took much longer than I had expected because I was very conservative in terms of feed and plunge rates, I could easily triple those with no problems.  It came out a little ragged, but with just a minute with a palm sander looked great.

There is a a video of the cut after the break: