We recently got our hands on Tormach’s new small form factor 4th Axis the microARC. Paired with some Fusion 360 beta 4th axis, this 100mm 4th axis rotary is a fantastic accessory for machinists at all levels. With a small footprint, the microARC is incredibly versatile – and its harmonic drive gearbox makes it incredibly rigid and nearly backlash-free.
The beauty of the microARC paired with Fusion 360 is the accessibility this brings to hobby users. The 4th axis is designed to fit on any of Tormach’s mills – from the hobbyist PCNC 440 to the prosumer-level MX line – offering new capabilities that machines at this level may not have had before. Leverage these capabilities with Fusion 360’s positional and simultaneous multi-axis toolpaths, and this opens the door for functionality that was previously unheard of at the hobby and even prosumer level.
We set the microARC up on our Tormach 1100MX using the SMW subplate, which allows for easy removal, setup, and repeatability of the 4th axis. Putting the microARC through its paces, we designed a part that would test both 3+1 axis machining AND simultaneous “true 4th axis” machining. When 3+1 machining, the 4th indexes between cutting operations. During simultaneous work, the A-axis is rotating while at least one (but often two) additional axis of the machine is moving, allowing the machining of geometry wrapped around the part or would otherwise require 3D surfacing.
Fusion already supports simultaneous machining: 2D pocket, 2D Adaptive, and 2D Contour allow the toolpath to be wrapped around cylindrical features. But what about more complex features? Fusion has two additional toolpaths that support complex simultaneous 4th axis machining: Flow and Rotary. Both toolpaths are both in beta (at least as they related to 4th axis CAM), but still worth testing. The video below walks through tips and tricks on how to program them, including how to access the beta mode!