2021. szeptember 25., szombat

CNC Router Reborn 1.

Back in 2014 I bought a CNC Router on the Aliexpress. I learned how to use it. It had several issues, what I wanted to, and started to fix.

Exchanged the undersized linear power supply to two switching ones, designed (and put substantial amount of work) into a new spindle controller. Made several mistakes (like broke one of the power supplies, later killing it completely during a repair effort). Even designed (and started to build) a dust collector for it.

At the end of the day I realized, that the unit will never fulfill my requirements. So I gave it up. Once collected some controller parts, to make it work just on "as is" bases, but left the thing lying around in my workshop.

The substantial problems I had:

  • Realized, the the 3040 form factor just a bit small for me. I rather go with 6040 or even 6090
  • The 300W (later changed to 400W) spindle motor is too small for me. The used brushed DC motors have very low torque at low speed. For milling aluminum it would need low rpm, high torque. I can't put bigger motor (or even low power BLDC) into the 52mm holder. To put a bigger holder I would need to replace the complete Z-Axis, as the holder made from a single piece of metal with the bearings and ball screw nut integrated.

Finally I decided, it would cost to much, to make it perfect, while the size kept still too small.

I'm here around 5 years after I last touched it.

I constantly pushing my son, to do something other than computer games, in his free time. A few weeks earlier he come up with some idea. We realized that he will need a CNC Router for his project.

I felt, that this is a good opportunity to rebuild my CNC router and also put me back on track.

The plan:

Build a new controller box for the CNC router, put together a new toolchain for it. I want to do this with mainly the parts I already have. The goal is to sell the CNC3040 at the end of the day to be able to build a bigger one.

The control box:

An old PC midi tower. This kind of thing always lying around as I live from computers in the last almost 30 years.

  • A mini-ITX motherboard: Gigabyte GA-E6010N - this one I bought newly
  • 8GB DDR-3 RAM - had it already
  • 60GB SSD - had it already
  • 600W 48V PSU for the spindle motor - from the last CNC repair effort
  • 100W 24V PSU for the stepper drivers - from the last CNC repair effort
  • 350W Chieftec PC PSU for the motherboard and the GRBL controller - had it already
  • Solid State Relay - had it already
  • GRBL controller board - bought for the CNC years ago
  • TB6600 stepper drivers - bought for the CNC years ago
  • Spindle speed controller - bought for the CNC years ago
  • Connectors - scavenged from the old CNC controller box

1. I put together just the PC on my desk to install the control software

Installed an Ubuntu Desktop 20.04 LTS onto it. Switched to LXQt to decrease the resource requirements. Installed Docker on it (from my work I became a Docker junkie in the last years), and added a CNCjs container. It still need some tuning, but it can only be done, when the controller is connected and I see what needed.

First mission accomplished. The CNC.js started to work.

2. Start to put together the control box

Drilled out some pop rivets from the PC box back. Removed the extension card holder/ATX cutout assembly. Cut it into two piece at the first extension card (the first card can be used even on a mini-ITX board). When it was done, put it back with new pop rivets.

Cut a few HDD holder ears in the 3.5" bay. It was needed to be able to assemble the 100W PSU in. Fortunately there was a few holes on the bottom for mounting the PSU without drilling.

Cut two L shaped aluminum extrusion for the 600W PSU to fit it into the 5.25" bay. After some drilling, threading, sanding, it went into it's place.

From the old PC PSU connector male (I have it unassembled) created a cable for the SSR and assembled the SSR in (It fit into the holes of the case top fan).

The idea with the SSR to be able to start the two additional PSUs when the PC soft start button pushed.

I altered the PC PSU a bit.

  • Added a bigger hard switch to be able to handle the two additional PSU
  • Added a screw terminal block switched mains output - I don't want to see more than one mains outlet at the back of the box.
  • Replaced the noisy (faulty) fan

Assembled the things above plus the PC motherboard, SSD drive into the cabinet.

I know, that this thing doesn't look more like a standard PC (nothing interesting in it, we built like this hundreds of times), but more to come.

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