Machining Hard Materials with Mastercam Art
When machining hard materials with Art, the goal is to cut a smooth surface with a constant scallop and to engage the tool in ways that avoid breakage. Avoiding breakage requires minimizing retracts, directional changes, and tool burial. Most susceptible to breakage are fine tipped tools that are used for high-detail work.
Here are a few Mastercam Art toolpath strategies for cutting hard materials and non-ferrous metals.
Parallel Spiral Contained, Single Boundary (conservative strategy — long run time, fine finish)
Most coin cutters use this strategy. They pick the coin’s outer edge as the containment boundary and let the toolpath flow over the entire coin, even the flat faces, using the outside-in approach. To go inside-out, you must start with a slow plunge to avoid shocking the tool. If you pack your toolpath tightly, the program will run long, 12 to 24 hours, but your tools will not break. The end result is a nicely polished coin.
Parallel Spiral Contained, Multiple Boundaries (shortened run time)
Improve your turnaround time by not cutting the coin surface’s flat top. Select only the outer boundaries of the geometry and letters, and do not nest containment boundaries. On the letter “Q” illustrated here, you would select only the outer boundary, not the inner, and let the toolpath flow over the flat area in the middle. The rule of thumb is to select only the outer boundary of any letter or geometry. This ensures that the cutter remains engaged, cutting only the tool Stepover amount without burying the tool. Cutting from the outside-in is the best practice in this example.
Parallel Contained, Multiple Nested Boundaries (shortened run time)
If you want to use multiple nested containment boundaries, change the toolpath angle from zero to 0.5 degrees (or more). Then, unlike with a toolpath angle of zero, the cutter will not be buried.