From Digimaken wiki
The MicroMill is a 2017 Kickstarter project to promote a small desktop cnc milling machine.
- Kickstarter page: https://www.kickstarter.com/projects/rp3d/the-micromill-a-desktop-cnc-milling-machine/
- MicroMill homepage: http://rp3d.co.uk/
The MicroMill is driven by an Arduino UNO (clone) with a Protoneer CNC shield from Protoneer (Ebay). The board is equipped with 3 Stepstick stepper drivers. Only the Z-axis driver has a cooler installed.
CNC Shield wiring
- Power supply on Blue screw terminal
- Green button to Resume
- Red button to Abort
- Door to E-Stop
- Yellow wire to SpnEn (single wire on white pin)
- Red/Black wire to 5V/GND (between Blue screw terminal and reset)
- 3 stepper motors (X, Y, Z) to 4-pin connectors next to stepper drivers
The relay board contains two relays, seperately switching Neutral and Live 220V wires to the Proxxon Spindle. Connections:
- Red wire to JD-VCC on conn1
- Yellow wire to VCC on conn1
- GND on conn1 is not connected
- GND to GND on conn2
- IN1, IN2, VCC on conn2 are not connected
The power supply is Mean Well IRM-30-12ST (12V / 2.5A)
Connecting a Probe
According to the GRBL documentation, a probe should be connected to Arduino pin A5:
The G38.2 straight probe and G43.1/49 tool offset g-code commands are now supported. A simple probe switch must be connected to the Uno analog pin 5 (normally-open to ground). Grbl will report the probe position back to the user when the probing cycle detects a pin state change. (https://github.com/grbl/grbl/blob/edge/README.md). Whatever probe you design should be able to handle some over travel, the Z movement likely won't stop immediately. Some sort of spring arrangement would do.
So the probe is anything that will take pin A5 to ground when it touches your object. The probe position is relative to machine 0. A typical porbe command might be G38.2 X20 Y15 Z-100 (in mm mode). You should set a slow feed rate , e.g. F20 (20mm/min). The G38 will move to X and Y, then Z axis will lower to -100 until the probe makes contact with your object, at which time movement stops. Grbl will report the machine position of the probe touch. https://github.com/grbl/grbl/issues/464
Arduino pin A5 is available as "SCL" on the 8-pin breakout, two pins further is GND, so I attached a 3-pin connector here.
To connect a probe, I most likely need to change the GRBL image on the Arduino (probing not enabled?). First I need to find out about the current setttings, using https://github.com/gnea/grbl/wiki/Grbl-v1.1-Commands