The Frog: CNC Router

Inspired by the OX (really cool!) the "Frog" is a CNC Router, using many parts from OpenBuilds.

Presently in conceptual form, there are a number of adaptations I want to flesh out -- time will tell how successful:

1. The slaved motors for X (Y?) are under the chassis, much like the original "Routy", with belts out of the way of landing dust.
2. The two halves of the gantry carriage are spaced/held by independent bolts, not the roller bolts. Should be easier to get aligned.
3. The Z-Axis is rack and pinion. They're not cheap, but they do take up a bit less real estate and fit well with the symmetric two-motor mount. BTW the two gantry carriage plates are identical.
4. I used NEMA 23's all around.
5. All assemblies are designed to permit easy squaring and locking, with liberal use of eccentric mounts for rollers.
6. All custom plates are designed to be rough-cut on cnc plasma, then post machined for precision hole diameters and placement. At some point in the future I'll likely produce 2D drawings with datums to help machining on a DRO miller.

I have included the most up-to-date version of the SolidWorks files, in Pack and Go 2010 format. This should be everything that's currently part of this build.

I welcome any/all feedback, and will post as appropriate as I get closer to building this puppy.

Neil

1/4/2014 Update: I have modified the rail mount a bit to allow for a simple vacuum box. Not fully detailed yet, but here's the concept (SolidWorks models have been updated in the Files area). I have added a third 2x3 wood strut in the middle.

1/25/2014 Update: The build is going well, have created a few helper features, such as belt tensioners for x-drives, a z-axis limiter (it falls when the power is off), and hose-clamp mounts for the router motor.

1/27/2014 Update: The Frog LIVES! Today I made the (obligatory) name plate for the Mrs. The machine worked without a hiccup, definitely need to install some kind of chip vacuum system. My next endeavor is checking out software that can do contouring -- ArtCAM Express looks like a good deal.

2/14/2014 Update: After a couple weeks of usage, here's my take on how the Frog is performing:

1. The reliability has been excellent, particularly the (admittedly cheap) electronics, in conjunction with Mach3. I made the right choice for this one.
2. The rigidity of the overall system is OK but not super. I have noticed a small bit of chatter on some cuts, mostly due to slight flexing of the various frame components. Depending on the speed and depth of cut, sharpness of the bit, hardness of the material, climb-milling or not, I can occasionally get slight "corduroying" of the cut surface. Only happens on rough cuts.
3. I've had to tighten the long x-axis belts due to a bit of detectable backlash in the pulleys. I am getting ready to change to 3mm GT2 parts, interested to see if this helps.
4. I built a vacuum motor box with speed control for the vacuum table, see photo. Much more reliable than using a shop-vac. Notice the muffler, home brew and quite effective. The vacuum table itself has worked very well, particularly with the new vacuum motor.
5. I made my first 3-d shaping cuts, a sample from ArtCam Express (which I have ordered). 1/4" roughing, then 1/8" ball nosed bit for detail. See photo, took almost 2hrs to make, but the result is good.