The following operations are never auto-assigned, but are useful in many cases for which the auto-assigned operations are infeasible:

Undercut walls can be made by T-slot cutters with the Undercut Milling operation.

You can assign Undercut Milling to two types of GCDs:

When you assign undercut milling to a GCD, adjacent GCDs might be handled by the same operation; be sure to assign the operation No Cost Feature to such adjacent GCDs.

The following illustration shows a planar face (in yellow) to which it is appropriate to assign Undercut Milling:

Given the assignment of Undercut Milling to the planar face as shown above, the following illustrations show the surfaces (in yellow) to which it is appropriate to assign No Cost Feature, since these surfaces will also be created by the Undercut Milling operation:

The following illustration shows a curved wall (in yellow) to which it is appropriate to assign Undercut Milling:

Given the assignment of Undercut Milling to the curved wall as shown above, the following illustrations show the surfaces (in yellow) to which it is appropriate to assign No Cost Feature, since these surfaces will also be created by the Undercut Milling operation:

Sometimes use of Undercut Milling renders feasible other operations on adjacent, partially obstructed surfaces, because the obstructed section is indirectly machined by the Undercut Milling tool. Consider, for example, the following illustration, which shows planar faces and curved walls (in yellow) to which it is appropriate to assign Undercut Milling:

The lip around the part’s interior partially obscures the interior floor of the part (which makes auto-assigned facing infeasible). But the obstructed section of the floor is indirectly machined by Undercut Milling, and the remaining portion of the floor is accessible to facing. So in this case, the interior floor of the part should be manually assigned Face Milling, with feasibility checks disabled. No Cost Feature operations should be manually assigned to the underside of the lip.

When you use Undercut Milling, you must supply a value for the process setup option Maximum Undercut Depth (right-click Undercut Milling node in the Operation Sequence Selection editor, and select Process Setup Options…). Enter a value in millimeters with up to 2 decimal places. This value is the largest distance from a point on the selected surface, along the normal to the surface at that point, to the end of the undercut. The arrows in the figures below show the undercut depth:

Tool diameter is set to two and half times the maximum undercut depth, by default. You can override this default with the operation-level setup option Requested Tool Diameter.

Cycle time for this operation depends in part on the following:

You can override the calculated cycle time with the operation-level setup option Requested Cycle Time.

This operation is available for the following processes:

Chamfer milling: narrow, angled planes can be made with a chamfering end mill. Use this operation for GCDs that are not recognized by aPriori as chamfered edges.

You can assign Chamfer Milling to two types of GCDs:

The following illustration shows planar faces (in yellow) for which Chamfer Milling is appropriate:

The following illustration shows ruled, curved surfaces (in yellow) for which Chamfer Milling is appropriate:

Cycle time for Chamfer Milling depends in part on the following:

You can override the calculated cycle time with the operation-level setup option Requested Cycle Time.

This operation is available for the following processes:

Mill grooving: O-ring grooves can be made with a keyseat mill. Use this operation for combinations of curved walls, curved surfaces, and planar faces that are not recognized by aPriori as a ring.

Assign Mill Grooving to a planar face, and consider assigning No Cost Feature to some or all of the surrounding surfaces.

The following illustration shows a planar face (in yellow) to which it is appropriate to assign Mill Grooving:

The tool is assumed to be a custom fit for the slot. Tool height is determined by the width of the slot. Tool diameter is determined by the depth of the slot, by default; you can override the default tool diameter with the operation-level setup option Requested Tool Diameter.

Cycle time depends in part on the following:

You can override the calculated cycle time with the operation-level setup option Requested Cycle Time.

This operation is available for the following processes:

No Cost Feature: if an operation indirectly machines adjacent GCDs along with the GCD that the operation is assigned to, assign No Cost Feature to those adjacent GCDs, to prevent double-costing. See, for example, Undercut Milling, above.