Tutorial: Using Avoidance Geometry

Avoidance geometry ensures that machining operations do not occur in specific portions of the stock for the selected setup/workpiece, such as the space under the part or between the vise jaws.

These blocked out portions (Avoidance geometry) are different from fixture bodies. While fixture bodies MUST be avoided, the Avoidance Geometry is considered part of the stock and may be gouged in specific cases. For example, drilling a through-hole may pierce the avoidance geometry but not the fixture.

Fixture bodies also require clearance from any tool, whereas all roughing tools may touch the surface of the Avoidance geometry.

Avoidance Geometry options

The Avoidance geometry feature is available for each ‘Setup’ within the ‘Target Setups’ section of the Setup tab, as shown in the image to the right.

An important point to note is that using Avoidance geometry is completely optional, you could take either of the following actions:

• Specify avoidance geometry for any of the setups that you have checked (see below)

• Don’t specify Avoidance geometry.

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Using Avoidance geometry

To use Avoidance geometry, take the following steps:

The relevant ‘Setup’ must be checked (see the example to the right).

The 'Avoidance Geometry’ icon, in CAM Assist (shown in the image to the right), is used to indicate that you want to specify the relevant portion of the model/part within Siemens NX.

Within Siemens NX:

Two things happen when you click on the model/part (as shown in the image to the right):

1. In Siemens NX - the selected area is highlighted.

2. In CAM Assist - ‘Avoidance geometry (0)’ changes to ‘Avoidance geometry (1)’.

That’s it, avoidance geometry has been specified for this specific Workpiece/Setup.