DIY CNC machine (GhettoCNC)

A cheap CNC router you can build yourself. If you have a 3D printer, that is …

Having salvaged 6 NEMA23 stepper motors from some old HP printer/copiers, I had an itch that needed scratching – they simply had to be used for something. As they were a bit big for a 3D printer (another project), I thought that I would have good use for a CNC router in my workshop.

The goal was to get a cheap CNC router up and running, using my previous experiences with my Kossel Clear delta 3D printer, and also designing and building a larger delta 3D printer.

The goal was a sub $300,- CNC router, not counting the parts I had already.

Stuff I had

  • 6 x NEMA23 motors
  • Arduino MEGA + RAMPS1.4 board with DRV8825 stepper drivers
  • 24V 5A powersupply (or 2 x 12V 35A in series after making them floating on the 12V side)
  • White enclosure for the electronics
  • Connectors and CAT5 cable
  • Microswitches for endstops

Stuff I needed

  • 3 x 4040 Aluminum extrusions 110cm (€15 each)
  • 1 x 4080 Aluminum extrusions 30cm (€7)
  • 30-40 x 8mm t-slot fasteners and 4mm bolts (€15 total)
  • 12 x 12x6mm bolts with flat head (for X to Y adapter fastening and for Z-carriage to 4080 extrusions)
  • 3 x 1M M10 threaded rod + 1 x 30cm M10 threaded rod (€12 total)
  • 22 x M10 nuts (€5)
  • Solid State Relay (€5,- eBay)
  • 20 x 26x10x8 (6200ZZ) bearings from ebay (€10-20,- cant remember, they were cheap, also eBay)
  • Base plate to mount everything on – MDF 1220x2440x22mm (€60,- local shop)
  • Router (€60,- eBay)
  • Lots of custom 3D printed parts (€40,- approx 2kg including prototypes and fumbles)
  • My wifes patience and forgiveness (can´t be bought, but was granted)

Everything above is UNVERIFIED and from memory. Please plan accordingly if you try to duplicate this.

Here is what I ended up with ….

IMG_20140924_195117

This is the one of the motors that started the project. An unspecified NEMA23 motor, 1.8degree steps and probably beefy enough for my purpose.

IMG_20140917_082736This is the router I bought off ebay, it’s 850W 11-33KRPM, with a nice 44mm mount. It came as a complete router kit, with mount etc. for hand use, but I only needed the motor. Also it included a 6mm and 8mm chuck. I’ve ordered a 6 to 3mm converter on ebay, so I can use Dremel bits.

In the background you can see the Z-carriage being printed on my 3D printer.

IMG_20140918_211630This is the base plate for the CNC router, turned upside down. It’s 1220x1220mm.

I cut some 9cm wide MDF parts and glued/screwed them onto the sides to make the base more rigid. Also I screwed on some 20x20mm square aluminum extrusions on, for even better stiffness.

IMG_20140918_212230

This is a basic layout of the 110cm extrusions mounted with motors, threaded rods, bearings and carriages. I have two Y-carriages and one X-carriage. In the background you can see the Z-carriage mounted, but the motor isn’t mounted there yet.

IMG_20140920_094527

Both Y-axis mounted on printed bases, with threaded rod through base and into aluminum extrusions with T-slot connectors. I used M6 rod for this. Excuse the mess, but that’s how I work.

IMG_20140920_175745This i my bunch-o-wires setup. I’ve terminated everything in CAT5 connectors, as a friend gave me a bunch of used ones to play with. CAT5 cable is rated for 0.5A per wire, so I should be able to safely run 1.0A through 2×2 wires. Obviously I’m running 2.2A on them, and that seems to work. Assume nothing I guess. In the box, the red wires are for the motors, and the CAT5 are for logic (endstops).

IMG_20140928_151605

First run! Everything worked as expected …. except the Z-axis. The Z-carriage is sticking too much to the extrusions, and the stepper has problems pulling the Z-carriage up in a reliable fashion.

IMG_20140929_165913After some minor adjustments, I tried cutting some numbers out. That went well, except for the 3 and 8 not getting cut apart, because I placed them too close together. Ah, a learning experience this is 🙂

IMG_20141001_085905Dust shoe. Highly needed, as my threaded rods were getting gummed up with sawdust quickly.

STL files are HERE. Everything was printed in PLA with 0.25mm layer height, 40% infill. The Z-axis part took almost 12 hours, but came out perfectly first time (it weighs 250 grams).

Feel free to comment below.

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One Response to DIY CNC machine (GhettoCNC)

  1. Marcelo says:

    Hello ! Please you would like to send me the motor wiring diagram KH56JM2U047 Thank you!

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