Configure Two Axes As A Tandem Axis - Fagor CNC 8060 Installation Manual

11.2
11.
CNC 8060
CNC 8065
(R : 1709)
EF
·552·

Configure two axes as a tandem axis.

A tandem axis consists in two motors mechanically coupled (slaved) and making up a single
transmission system (axis or spindle). Only one axis (master tandem axis) can be displayed
and programmed at the CNC. The other axis (slave tandem axis) is not displayed and is not
programmable; it is controlled by the CNC.
The following aspects may be pointed out in this configuration:
• A tandem axis helps provide the necessary torque to move an axis when a single motor
is not capable of supplying enough torque to do it.
• Applying a pre-load torque between the main motor and the slave motor reduces the
backlash on the rack and pinion.
• The rigidity of the rack-and-pinion system is greater than that of long leadscrews.
One of the many applications for the control of a tandem axis has to do with Gantry machines.
The following example shows a gantry axis with two tandem axes.
Requirements and limitations of tandem axes.
Each tandem pair (master and slave) must meet the following requirements:
• Each master tandem axis (spindle) admits one single slave tandem axis (spindle).
• A preload may be applied between the two motors.
• Each motor may have a different rated torque.
• The turning direction of each motor may be different from the other's.
• The torque distribution between both motors may be different from 1:1 ratio. For example,
on motors whose rated torque is different.
• Both axes and drives must be of the same type (same AXISTYPE and DRIVETYPE
parameters for both axes).
• The channel changing permission (parameter AXISEXCH) must be the same in both
axes.
• Both axes and drives must have the same software limits (same LIMIT+ and LIMIT-
parameters for both axes).
• When the axes are rotary, both axes must be of the same type (same AXISMODE and
SHORTESTWAY parameters for both axes).
• The fast and slow home search speeds (parameters REFFEED1 and REFFEED2) must
be the same for both axes.
I n s ta ll a t io n ma n u a l.
Example of a tandem axis made up of two
pinions and a rack.