Indexing Overview

The Indexing feature in EZ-MILL is used to rotate the part between part program Work Steps, when the tool is withdrawn to a clear position. The next machining Work Step does not begin until the part has been secured again, and rotation does not occur until the end of the part program Work Step. This allows one or more machining operations to occur on different planes of a part. For instance, contours may be cut on the different sides of a box-shaped part using the Indexing feature.

In each Work Step of a part program, the Machining Coordinate System (MCS) can be changed. In order to rotate the part using the fourth axis, the part program must use the MCS to identify the work planes of the part. It is the difference between one MCS and the next that causes the rotation of the fourth axis. The part is rotated so that the MCS named in a new Work Step matches the Z axis of the machine. Since the cutting tool must match the Z axis of the part program, this is the critical axis which causes rotation. The origin in the XY plane is shifted, once the rotation is completed, to match the new Work Step’s origin.

To set up a part program that will properly make use of the Indexing feature, you should create your User Coordinate Systems so that the Z axis will be parallel to the World Coordinate System axis when the rotation occurs. That is, only rotate the UCS about the axis on which the rotary table is set. If the Z axis of the UCS is not parallel to the machine’s Z axis when the rotation occurs, an error message is returned when verified.

The easiest way to be sure that the UCS matches the World Coordinate System when the rotation occurs is to use the On Geometry command to establish the UCS origin and orientation. As long as you use lines that are parallel to the World Coordinate System axes to establish the UCS, the Z axis will have the correct orientation when the part is rotated.

Note that in each Work Step the Z Surface value is relative to the origin of the User Coordinate System which is identified as the Machining Coordinate System. Also ensure that the correct Indexer option on the Verification tab of the Work Step Data dialog is selected before prior to posting.

Click here for graphic explanation

Interactive Graphic - VERIFICATION Tab

4th Axis Surface Machining