Mastercam Slot Mill

Let’s take a look at how to use Mastercam Slot Mill to program undercuts using settings in the depth cuts utility. For this example, we will use the Circle Mill toolpath. Open the Circle Mill toolpath and select the geometry.

Mastercam Slot Mill

The depth cuts are going to be set as step ups from the bottom to top, using the top of the slot mill to create the undercut. You can select either the upper or lower geometry. The depth of the undercut geometry is 0.400 thousands so we will use a tool that evenly divides into that value.

Mastercam Slot Mill

In this example, the thickness of the slot mill is 0.100 thousands. Set the finish passes for one pass and make certain the toolpath is set to start and return to center in the Transitions page under Finishing.

Mastercam Slot Mill

Go to the Depth Cuts page and activate the utility. Set the max rough step to 0.100 thousands. Set the depth cut direction to step up and check the box for undercut to activate the strategy.

Mastercam Slot Mill

Go to the Linking Parameters page. The top of stock is set to the upper edge of the undercut, the depth is set to the bottom of the cut. These settings should result in 4 step-ups to cut this geometry.

Mastercam Slot Mill

What if we want to use intermediate step-ups instead of the full thickness of the tool, say 0.050 thousands. Change the depth max steps to 0.050 thousands then go to the Linking Parameters settings. We will need to edit the final depth. The max steps are half the thickness of the tool so add this value to the final depth, in this example 0.050 thousands. These settings should result in 7 step-ups to cut this geometry.

Mastercam Slot Mill

What if you want the step-ups to be 1/4 of the tool thickness, in this example 0.025 thousands? Change the depth max steps to 0.025 thousands. We will need to edit the final depth. Add the max step value plus half the thickness of the tool, in this example 0.075 thousands. The math works out the best if you use full thickness, 1/2 or 1/4 the thickness of the slot mill. These settings should result in 13 step-ups to cut this geometry.

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