Intro: Desktop CNC Machine
This is a CNC machine made out of left over parts from my schools robot build. The only thing we paid for was the circuit board to run it. Grand total of about $70. This was made with no directions, all of it was trial and error. This should get you started if you want to build one.
1. I started with an aluminum base (19.25 wide, 13.5 deep and .25 thick)
2. On to that is mounted the two uprights (10.25").
3. And in between is the cross brace (16.25")
4. Also mounted to the base is two pieces of 1.5" aluminum angle which two 24" full extension drawer slide are mounted to for the Y Axis.
5. We used Accuglide rails and slides for the X and Z Axis.
6. For the X the slide rails are mounted to a piece of aluminum (3 x 19.25 x .5)
7. The X axis gets mounted to the two uprights. It is adjustable the way we did it, so we can adjust for our dremel travel.
8. Next I made the Z axis slide. Its another piece of Aluminum with the slide rails mounted to it.
9. We made some 1" x 1" x .5" aluminum blocks for spacers for the Z axis.
10. Those are put on and it gets mounted to the slides on the X axis.
1. Next I made some mounting brackets for the motors. Its kind of hit and miss with these. You may have to make a few before you get all the clearances you need. I made these out of 1/8" aluminum. X is just a flat piece, the Y and Z are 1/8" aluminum with a 90 degree bend.
12. The X gets mounted to the same piece of aluminum that the X slide rails are mounted to. That way the motor moves up and down with it if it needs to be adjusted.
13. The Y axis is centered between the two drawer slide and screwed to the base.
14. The Z is mounted to the Z axis. you may need spacers to get the right distance for clearances.
15. Next i cut some 1/4" threaded rod close to the lengths I needed. On to one end I put a bearing on the rod. We got the bearings from some old VCR's. There are two bearings in the video heads of the VCR that fit the rod perfect.
16. You need to put one bearing on the end of each axis rod.
17. Next I made some steel brackets that the coupler nut is welded to, it makes the different axis move when the motor turns.
Again this is hit and miss, you need to measure you machine for sizes.
18. After those are made you can start to mount them. I started with the X axis. I threaded the bracket onto the X rod and attached it to the motor with some plastic tubing we had. The tubing actually works really good. It threads onto the rod and fits tight on the motor shaft.
9. The other end of the X axis is held in place by a bracket mounted to the upright, and the bearing is held to that by some self tapping screws.
20. You need to screw the X axis coupler bracket to the Z axis so it can move back and forth. You need to drill and maybe counter bore your holes so you have clearance and check to make sure the screws are not in the way of the X axis rod.
21. The Z threaded rod is held onto the motor with the same tubing as the X. Thread the Z coupler bracket onto the Z threaded rod and mount that to the motor. The bearing is held in place with a few screws again. The bracket will be screwed to the slides along with your tool holder.
22. The same goes for the Y axis under the table top. Bearing is held with some self tapping screws.
23. The table is just a 3/4" piece of MDF plywood. There are two pieces of aluminum angle screwed to the edges of the MDF.
Then the two drawer slides are screwed to those.
After you get the table ready, slide it in and make sure it slide back and forth OK. Next you screw the Y coupler bracket to the back edge of the table. And screw the bearings in place.
24. You should have the motors and all the brackets mounted. Next is hooking up the wires.
25. We used a 3 Axis TB6560 CNC Driver Stepper Board Controller 2.5A. We bought it off ebay.
26. The instructions tell what color wire goes where and also what your pin numbers are for the parallel port.
27. We used AutoCAD and AutoCAD inventor to draw things up. Then we used Visual Mill, and Lazy Cam to generate the G-CODE. Visual Mill is FREE and works great.
28. Mach 3 is used to load the G-Code into and run the machine. Mach 3 is free, but you can only run so many lines of code.
29. You need to calibrate to machine. Each one will be different, depending on your motors degree per step, and size and number of threads on the rod. I put screen shots of all the settings I used in Mach 3.
30. You can add limit switches and home switches if you want them. I would recommend an E-STOP button on the machine just in case.
31. After it is calibrated, you draw something up, save it to the right file format, and load it into your g-code and tool path generator. That was Visual Mill or Lazy Cam for me.
32. Those programs will generate the G-Code. It will be a .tap or .nc file.
33. Load the G-Code into Mach 3 and do a dry run first. After you are sure it is ready try a test piece.
34. WEAR SAFETY GLASSES!!! The bits do break.
35. After a little trial and error, you will get it.
There is a picture of a scorpion the CNC routed out with red LED's to light it up!!!