Operator`s manual

Advanced Haas Mill Programming Techniques Training Manual Page 66
Above shows the HA5C mounted along the X-axis of a vertical machining center.
Haas indexers are set up two different ways: Semi-Fourth and Full Fourth Axis Operation. In the semi-
fourth mode a separate servo controller with a completely separate program controls the rotation of the
work piece. The host machine sends out a M21 command, the indexer rotates the amount indicated in its
internal program and then sends a finish signal back to the host machine. The host machine then performs
a machining operation and then sends another M21 command to the servo controller. The servo controller
then rotates the head the number of degrees indicated in its 2
nd
line of program and sends back a finish
signal. Then machining is performed by the host machine at that particular angular location. In the “semi-
fourth axis” mode the rotary device cannot do simultaneous interpolations with X, Y or Z axis. Only when
the rotary unit is directly interfaced with the host machine may full fourth axis operation be performed.
See illustration below.
Illustrations taken from Haas 96-0315r rotary pdf - Haas Rotary/Tailstock Operators Manual December
2012