CNC machines are great at milling flat surfaces, even if the mill is the DIY kind, but only if the table is perfectly flat, or as close to it as possible. However, what happens if the piece you are milling isn’t perfectly flat or curved for that matter? This is where autoleveling comes into play, which has become commonplace on most new CNC machines and 3D printers and helps keep the piece as flat as possible while being machined.
While some may prefer to buy their machines with autoleveling capabilities built-in, while others prefer to go the DIY route. This often means they will have to create their own leveler, which is what German tinkerer Tobias has done by designing an interface that uses a Z touch and BLTouch probe for his GRBL-based CNC machine.
Tobias explains, “This Z touch probe is actually meant to be used for autoleveling the print bed on a 3D printer. But because the machine table of my DIY CNC is not perfectly even, I wanted to use it for autoleveling on non-conductive surfaces, like acrylic.” For conductive surfaces, the BLTouch is not needed, as using a crocodile clip attached to both the milling bit and the conductive material will complete the circuit.
Tobias designed a custom PCB that uses an ATtiny10 MCU to control the BLTouch probe, which is connected via color-coded pinouts soldered to the board, by sending pulses of different widths. He also installed a button for putting the machine into different modes- ½-second press deploys the probe, one-second press stows it, and a two-second press stows it and activates an alarm release. Tobias has uploaded a detailed walkthrough on his project page for those interested in building their own autoleveler.
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Author: Cabe Atwell