Simultaneous 4th Axis Machining with Fusion 360!

What is Simultaneous 4th Axis?

4th Axis CAM  and 4th Axis machining can be handled in one of two ways: positional or simultaneous. Positional 4th Axis, or 3+1 machining, involves moving the 4th axis of the machine in between cutting material. This comes in handy when for example you need to machine a piece of roundbar to have a square on the end – each side of the square is its own distinct plane, so the 4th axis only needs to move in between cuts. Simultaneous 4th Axis (sometimes called true 4th axis) machining involves the 4th axis moving at the same time (simultaneously) as the X, Y, and Z axes of a traditional mill. Paired with some AWESOME toolpaths in Fusion 360 this allows us to machine features that would normally require surfacing or otherwise be impossible to machine without simultaneous 4th axis machining.

Fusion 360 4th Axis Toolpaths

Can Fusion 360 handle simultaneous 4th axis machining? Yes! There are quite a few simultaneous 4th axis Fusion 360 toolpaths, with some being only for cylindrical features and more being gradually introduced for more complex geometry:

  • 2D Contour – Fusion 360 can create a simultaneous 4th axis contour toolpath so long as the feature is cylindrical using Wrap Toolpath.
  • 2D Adaptive – Also using Wrap Toolpath, Fusion can generate adaptive toolpaths around a cylinder, allowing you to machine pockets or slots that wrap around the part.
  • 2D Pocket – Much like 2D Adaptive, Pocket can be wrapped around a cylindrical feature. This is because Fusion takes the feature and ‘unwraps’ it, generating the toolpath for a flat surface, and rewrapping the toolpath to the feature so you end up with a simultaneous 4th axis toolpath.
  • Rotary – The Rotary toolpath is the first simultaneous 4th axis toolpath in Fusion 360 that doesn’t require a cylindrical feature! Take a look at the video below for tips on how to enable this toolpath.
  • Flow – The Flow toolpath in Fusion 360 is a great solution for doing 3D surfacing when the part or geometry is not cylindrical. (Note that this toolpath is currently in beta)

Machining on the Tormach microARC

Tormach’s new microARC 4th axis is proof that good things do come in small packages! The microARC is a small/medium form factor 4th axis rotary with some great features: small footprint, through-bore spindle, and driven by a harmonic drive. This means you get an incredibly rigid and versatile machine accessory in a form factor perfect for any size Tormach mill.

Machining a Toothpick using Simultaneous 4th Axis Machining in Fusion 360

More 4th and 5th Axis Machining:

Autodesk University 2019: Growing into a 5-Axis
Fusion 360 4th Axis CAM Tutorial!
May the 4th Be With You! CNC Milling with a 4th Axis
4th Axis CNC Machining on Tormach with Fusion 360!