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On November 5th, 2009, I realized my dream of acquiring a CNC router.  I’ve been craving one of these cool gadgets ever since my friend Don Bailey (a frequent bad influence on me!) started building one several years ago, but it really came to a head when he finished it and I started seeing all the cool things he was doing with it! So, in mid-September, I ordered my own CNC Router and started working frantically to try to finish a workshop area in my basement to give the router a nice new home. I painted the floor with two coats of Epoxy paint, framed the room, ran four new electrical circuits (110 and 220), and almost finished hanging the drywall, but then the router came and I’ve been addicted to it ever since. (Kelly, I’m going to finish the workshop soon!  Honest!)  So, for the time being my router is sitting in the corner of my basement on the concrete floor, but it is happily churning out my new inventions as I come up with them.

I’ve made a lot of cool projects with my router already, and I’ll post them here and in my gallery as time allows.

Here is my current setup:

• A KT-2514S-09 4-axis servo driven router from K2CNC
• A Porter Cable 890 Router with precision ground 1/2″, 1/4″, and 1/8″ collets
• A 4U rack-mount PC running EMC2 for control
• A Shop-Vac hooked up through a Dust Deputy to a dust hood around the spindle for dust collection
• An MPG2 pendant I got this Christmas (Thank you honey!)  Integration info can be found here.

I’m also in the process of building a control box that will sit between my PC and the K2CNC provided motor controllers.  This control box will be the central location for the following:

• Hookup location for my MPG2 pendant
• Safety interlock and relay control for automatic control of power to my motor controllers, spindle, and vacuum.

Here’s the progress so far:

I’m doing this in two steps.  So far, I’ve made a quick and dirty board to just intercept pin 14 off the primary parallel cable and send it off to a relay board which then drives the solid state relay to control my spindle.  I’m also working on a better version that will provide additional safety by disabling power to the spindle, vacuum, and motor controller until a microcontroller receives a valid charge pump signal from EMC2.  You can see the board below, but I wanted to have something to work with until I got around to programming my microcontroller.  (It will be a Freescale MC9S08SH8 in case you’re curious.)

Typically, I design my PCBs in Eagle and have them shipped off for fabrication at either PCBFabExpress or BatchPCB, depending on my level of patience at the time.  This time around, though, I decided to try my hand at making my PCBs myself on my router with the help of the excellent open source Eagle plugin pcb-gcode.  Many moons ago, I used to make my own PCBs using direct etch or photo-resist methods, but I got sick of dealing with the etching chemicals.  But, since I have this fancy router laying around, I decided to give it a go.

In the interface pic above you can see my first primitive attempt at a PCB, replete with my mistakes. Here are some pics of my latest PCB that supports my microcontroller version which I’ll be installing as soon as I write the firmware for my microcontroller:

It took 6 tries to get to this.  (The 2nd and 3rd try are the mess on the bottom of the currently installed board.  The board is oversized to fit on the existing standoffs which is why I decided to just leave it there.)  The good traces on my currently installed board were made with a 10 degree V-Carve bit.  I tried a purpose built 60 degree isolation bit, but the Z level touch off is too critical, and my raw material quality is too poor to get consistent results.  So, I used the sharper carving bit with a deeper cut to get this to work.  I’m still not totally happy with it, but it will do for now.  The next attempt (displayed above) was made using a 25mil flat end mill. It did a very good job but the down-side was that if you don’t cut deep enough it tends to rip up the copper a bit, unlike a V-Carve bit which just makes a light engraving on the surface. This made me want to over-compensate on depth which resulted in through-cutting on a two-layer board with a thin substrate. The board above worked well because of the thick substrate. Also, obviously 25mil is on the large side of the scale for PCBs.

I have finally gotten a pretty good PCB routing process down using 15mil end mills and higher quality PCB material.  Eventually, I’ll redo my interface board with my new techniques.