Software for Rotary Indexing

There are essentially four different ways to machine something on a rotary indexer. They are:

  1. Turning (lathe style)
  2. Wrapping
  3. Multi-sided machining
  4. Simultaneous 4-axis machining

Before discussing specific software packages, it is helpful to understand the differences between these techniques.

1. Turning

This method is the most familiar to those who have used a lathe before. Essentially, the indexer rotates at a set speed, and the cutting bit traces the profile of the desired object. This method is rarely used with indexers because they cannot rotate at the same high speeds as lathes. However, there are some situations for which this method is the best choice.

2. Wrapping

Wrapping is the easiest method for software to generate a fully 3D toolpath for an indexer. The concept is simple: take a 2D toolpath, and “wrap” it around a cylinder. Take a look at the picture below left. You can see the shape of what looks like a newel post or stair spindle in blue – it was generated by simply wrapping the 2D pattern (visible in wood color to the right of the blue shape) around a thin cylinder.

Wrapping can be used to design complex spindles, posts, wrap lettering, etc. Bill Schober at Humble Sticks has made some phenomenal carvings using wrapping.

Wrapping can also be used in reverse, to “unwrap” a 3D design that already exists. This allows a complex design – such as a statue – to be toolpathed and prepared for cutting by software that normally only processes 3-axis machining.

The reason software programs wrap/unwrap a design is that it allows them to machine the 3D object while only dealing with 3 axes: the rotary b-axis, the z-axis, and either the x- or y-axis (whichever is parallel to the indexer). Essentially, the bit moves along a profile like it would when turning (lathe style), but the path changes each pass, and the indexer rotates. The video to the left shows the process in action.

There are some things, however, that cannot be accomplished with wrapping/unwrapping. In particular, anything that generates an undercut when unwrapped cannot be machined, as well as anything that requires cutting past the center axis of the blank.

3. Multi-sided Machining

This technique Is exactly what it sounds like: machining an object from multiple sides. The more sides you machine from, the more detail you can achieve. Multisided machining is generally the best technique for complex 3D objects such as sculptures or figurines.

4. Simultaneous 4-axis machining

Some software packages allow you to control all 4 axes simultaneously and specify the exact path of your tool. This is needed only in the rarest of cases.

Specific software packages

Below are the programs we recommend, however, there are many programs not mentioned that can be used to create toolpaths for an indexer.

VCarve

  • Free with the purchase of new ShopBot tools.
  • Turn (lathe style)
  • Wrap 2D and 3D designs, limited modeling ability
  • Import and unwrap a 3D model for machining

Aspire

  • An upgrade for VCarve. Adds the ability to model and manipulate 3D designs

Fusion 360

  • Free to use
  • Professional level modeling tools; extremely powerful but not as easy to pick up as VCarve or Aspire.
  • Model complex 3D objects and shapes
  • Turn (lathe style)

Cut 3D (formerly Partworks 3D)

  • An affordable option that allows basic 4-sided machining of .stl files. Generates 4 separate files for each side; indexer must be rotated in between
  • Does not have CAD capabilities – models must be created in another software (such as Fusion 360 or Rhino)

DeskProto MultiAxis

  • A capable CAM program allowing customizable multisided machining
  • Does not have CAD capabilities – models must be created in another software (such as Fusion 360 or Rhino
  • Does not provide cut simulation

RhinoCAM Mill Exp

  • Professional 4-axis machining plug-in for Rhino. Main advantage over DeskProto is the ability to simulate cuts

 

Each new ShopBot tool comes bundled with two powerful software programs to create CNC projects.

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