My first CNC

Finally, after a lot of false turns, I have both designed and CNC-ed an object.

It is a 18x1mm counter-bored 16mm hole for a flanged bearing, in a pleasantly-shaped piece of 4mm acrylic. After seven minutes of cutting, including the shaped perimeter, it came out just right, with the bearing a firm push fit (until I played with it too much).

Engineer in Wonderland CNC-related blogs are indexed here

The short story is:

Longer story:

This has been a multi-year spare-time long haul, with me buying a very cheap 1810 Pro machine at the start to make pcbs, and almost immediately wanting to re-design it to get the slack out.

Basically, I could not bear to learn on a machine whose bit has nearly 1mm of slack

This re-design got more and more ambitious, and there is a box of parts in the workshop still awaiting assembly.

Side-note 1: Early on, I broke a lot of 0.2mm cutting bits never quite making a pcb – learn basic cutting before attempting a pcb, is my advice.

In the middle of this, I found the spindle (cutting) motor ridiculously noisy, and splashed out on a superior same-dimensions brushless dc type – so much quieter, with an 8mm shaft instead of a flexible 5mm shaft.

Not so long ago I bought (no extravagance spared) an all-metal 1310 cnc router to compare my incomplete re-built 1810 to, and this became its own multi-week improvement project that involved learning a lot about fine adjustment and fettling.

This is now just about complete, with a 3d printed prototype adaptor (right) for the brushless dc spindle which is stiff enough for the slack in the linear bearings to be the main cause of error (a version with cooling fans is in the (over-long) personal pipeline – which will go on Printables if it works out).

Side-note 2: as far as I can see, you only run a desktop router on an open desktop once, before you go looking for a vacuum cleaner, and a cardboard box to catch all the tiny plastic chips next time.

After watching both JD Designs’ introduction to Easel videos, it was relatively quick, and most enjoyable, to design a simple part in Easel and cut it using Universal Gcode Sender (‘UGS’) running on a PC.

Easel is software from a company called Inventables which makes the rather nice X-Carve series of cnc routers – hats off to them for having a useful free version of the software.

UGS is an excellent open-source ‘gcode sender’ for cnc machines that use grbl firmware – hats off to Will Winder and the other people who have given up their time to make, maintain and improve this. (Here is how to get in running with Mint Linux), and also to those who created, maintain and improve grbl, which is also open-source (pre-v1.1 and the various v1.1 versions).

The 1310 is running so well, that the improved 1810 has once again been shelved, at least until it is wet and cold outside.

Side-note 3:, also in the Wonderland pipeline is a isolated pwm-to-voltage converter circuit that will interface a grbl control board (which is basically an Arduino with add-ons) to the particular brushless spindle motor control box that I have here. Design done, parts bought, just need to get a pcb made on the cnc – oh my word, the wheel turns full-circle.