5 Spindle Axis Operation
5.3.1 Tapping Position Management
5-16
5.3
Tapping Operation
This section describes how to implement tapping operation from the host controller.
Tapping with a
Σ
-V-SD driver is performed through interpolation control between the spindle and feed axes.
The host controller performs linear acceleration/deceleration interpolation calculations between the spindle
and feed axes each communications cycle. The results of those calculations are sent to the spindle and feed
axes through the MECHATROLINK-III INTERPOLATE or VELCTRL command.
Use the VELCTRL command if forming a position loop with the host controller.
Or, use the INTERPOLATE command if forming a position loop with the servo.
The position of the spindle axis is managed by the feedback value of the spindle axis pulse generator (or motor
pulse generator for direct drive systems), in the same way as for servomotors.
To perform tapping at a high speed and with high accuracy, you must take measures to reduce synchronization
error.
In order to implement an easy-to-use, flexible tapping function, you must include feed hold tap return, return
speedup, deep hole tapping, and inclined tapping functions.
Rigid tapping must balance the tap size, tap length, tap pitch, material, acceleration/deceleration rates, and
maximum number of revolutions based on the characteristics of the motor that is used.
The following system block diagram shows a position loop that is formed with the servo driver for the spindle
axis.
5.3.1
Tapping Position Management
There are two methods of tapping position management, as described below.
• Spindle axis rotation is performed with speed references. When tapping is started, orientation is performed
to determine the home position and manage the current position value.
• When the power supply is first turned ON, a phase-C latch is performed on the first revolution of the spindle
axis. This saves the latch position in the host controller and manages the current position value of the spin-
dle axis by determining the home position from the position offset between the phase C and spindle axis
home position.
Use one of the above methods to determine the home position and perform position management for tapping.
By performing position management for tapping, the position of the spindle axis can be managed whether
speed control or position control is used to rotate the spindle axis.
Spindle
motor
velocity/
position
loop
PG
Converter
SERVOPACK
MECHATROLINK-
III
Spindle
Tapping,orientation
contorol
INTERPOLATE command
velocity control
velocity command
Phases A/B and phase C
PN wiring
CN-3 pulse
pulse generator
channel 1