Simple DiY CNC

Video:  https://youtu.be/2uwbaxhc__I

Simple DIY CNC  using:

- 2 Printer Steeper ( X, Y Axis )
- 1 Nema 17 ( Z Axis )
- Arduino  Uno + CNC_Shield + 3xA4988.
- Hacked PC suply to 24 V.
- 20 608ZZ ball bearings.
- 8mm Screw Rods. (6mm for Z)
- 2 "V" Steel profile 1m 15x15 mm.
- 2 50cm Drawer linear rails (Y Axis).
- Some MDF.

Working Area: 45x45 cm.

Total Cost: less than $100.



This machine is very simple, mainly builded in MDF and some wood.

X-Z axis Block:
The rails are piezes of MDF with "V" Steel profile 15x15 mm.
I used 2 1m piezes, cutted in 600 mm for X axis and 400 mm for Z axis.

X Rail is 600x130 mm.
Z Rail is 400x105 mm.

Bearings are cheap 608ZZ, 8mm inside, 22mm outside. 2 bearings fit in the V profile.
They are grouped  in 4 groups of 4 bearings holded by 4 8mm screw.


All the X-Z axis bearings are mounted in 2 piezes of MDF 32mm thick, joined by 2 8mm screw, so it's posible adjust the bearings to the rails.

The idea is first adjust bearings to X rail,  then tighten the nuts of bearing screws, then adjust nuts of horizontal screws to adjust bearings to Z rail.



X axis is moved by a printer stepper and 8mm screw.
Z axis has a nema 17 and 6mm screw.



Y axis is mounted over 2 drawer rails.
It is not very stable but works better than i expected.



Y axis is moved by a printer stepper and 8mm screw.



This machine being just an "experiment" works better than i expected, but i learned a few "how not to do":

- Printer steppers do the job, but was very tricky getting them to work properly because they don't have too much power and are a bit high impedance.
They heat up notably, but not in excess.
Nema 17 are not expensive, so if you have the chance, buy them!!

- Drawer rails are easy to use, and not expensive, but not very stable.
In this case for Y axis the forces are aplied in a not too bad way so they do the job, but don't use for X or Z axis!!!... you will end up with an useless machine.
Bearings + V prolile is cheap, must be built carefully to get it perfectly parallel, but is not too difficult.
A bit tricky to get the bearings perfectly adjusted to the rail, but the result is much more strong and stable.

- I did the structure and X rail with 16 mm MDF, so it's not strong enought for many works.
Better go to something like 32 mm.

- Y axis base movable instead of a X axis "tower" and fixed base is good for small sizes. But if the base moves 45 cm you need 100 cm free space...

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