Actobotics CNC Mill

After several months, I picked this project up again. So yeah, I'm building a CNC mini mill. The sort of thing you could engrave a circuit board or something like that. I'm building it out of the very excellent Actobotics building system.

However, this February I got a very cool but brain-exhausting job that sort of derailed the project. I was able to scrounge enough brain cycles to take this up again--thanks in part to Actobotics for sending me some more parts!

So, my original concept called for a much higher gantry, on par with the 3D printer that I own. It's built out of Makeblock beams, which are very cool in their own right. For instance, did you know that Makeblock parts have a hole spacing identical to Technic LEGO?

Despite the coolness of the beams, however, their 3D printer was not a successful product. It was a wobbly sumbitch, I gotta say. It's possible that 3D printers made from building sets simply have too many connection point to be solid. So for me to model my mill, which surely will have MORE stress put on the toolhead, on same uber-high gantry, sounds like a fool's errand. I may need to get beams with more mass if I want to do any kind of precision milling--the Actobotics channels may simply lack the mass to asborb vibrations.

Then there is the infrastructure of a mill, much of which I lack and would have to buy. I need to get the actual rotary tool; I was going to start with a simple 12V drill motor with a chuck add-on. I still need limit switches, though I bet I could scrape some up in the basement. Still need  CNC controller hardware and servo motor controllers. All of this makes me think that I'd like to simply take the Makeblock printer's old extruder and the electronics, and move them over to Actobotics chassis and forget the mill. 

But would the Actobotics 3D printer be any more successful than the Makeblock one was? The #1 thing I felt I could do to reduce wobble was lower the Z-height to something fairly modest. What was the point of having a 6"-high build envelope if the damned thing is crooked? I can still do perfectly fine things with a shorter Z.

Another advantage to switching over to a 3D printer is that I work for a company that makes all sorts of flexible heaters, so building the perfect heated bed is totally a possibility.

The photo shows the new shorter gantry. The project continues!

Worked a little on the Y axis and gantry. I like it! It feels very solid. However, I do need to get the two Y-axis 8mm rods further away from the side channels. Another change is that the Y will be controlled by a stepper outside the main frame, with a 1/4" rod running through the whole width.

This is a partial list of Actobotics parts used in this project: 

Y-AXIS

1x 12” aluminum channel, P/N 585454
2x 3.75” aluminum channel, P/N 585443
4x 90-deg angle brackets, P/N 585532
4x 90-deg pattern mounts, P/N 585494
1x 12” d-shafting, P/N 634094
1x 1/4” to 4mm clamping shaft coupler, P/N 625049
1x aluminum set screw collar, P/N 9946K11
1x 1/4” ID x 1/2” OD flanged ball bearing 2-pack, P/N 535198
1x 6.25” x 7.25” ABS sheet, 1/4”, P/N ABS250-625-725
4x large square screw plates, P/N 585430
6x small square screw plates, P/N 585478
2x channel connector plate 2-packs, P/N 545532
3x 6-32 zinc-plated socket head screw 25-packs P/N 632114
20x 6-32 black-oxide socket head screws, P/N 91251A148Y-

X-AXIS

2x 8mmx250mm shafting P/N 634312
4x 8mm set screw hubs, P/N 545636
1x 2” d-shaft, P/N 634068
1x 3” d-shaft, P/N 634078
2x 8mmx45mm linear ball bearings (two 2-packs) P/N 535226
4x 21mm bore bottom tapped clamping mount P/N 585660
2x XL belt mount A, P/N 585502
1x 10-tooth pinion pully, 1/4” ID, P/N 615376
1x 3/8”x24” timing belt, P/N B375-460XL
2x XL belt mount A, P/N 585502
1x 1/4” to 4mm clamping shaft coupler, P/N 625049
1x NEMA 23 stepper motor mount, P/N 555160
1x 1/4” x 1/2” OD flanged ball bearing 2-pack, P/N 535198
2x 4.5” aluminum channel, P/N 585444

Z-AXIS
3x 6” aluminum channels, P/N 585446
1x 12” lead screw P/N 634050
1x 8mm lead screw nut, P/N 545315
1x 8mm lead screw barrel nut, P/N 545314
1x 4mm to 8mm clamping shaft coupler, P/N 625082
2x 8mmx300mm shafting, P/N 634314
3x 8mmx45mm linear ball bearings (two 2-packs) P/N 535226
1x NEMA 23 stepper motor mount, P/N 555160
4x 8mm bore bottom tapped clamping mount, P/N 585634