Tangential Control (T3)
22.4 Limit angle for reversal of path direction
Turning, Milling, Nibbling
388
Function Manual, 11/2012, 6FC5397-1CP10-5BA0
22.4
Limit angle for reversal of path direction
Problem
When the axis moves backwards and forwards along the path, the tangent direction turns
abruptly through 180 degrees at the path reversal point. This response is not generally
desirable for machining operations (e.g. grinding of a contour). It is far better for the reverse
motion to be executed using the same absolute offset angle as the forward motion.
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Figure 22-3 Path movement with direction reversal and alignment of follow-on axis
Solution and programming
A minimum and a maximum value for the position of the following axis ("C" in example), in
relation to the base coordinate system, are transferred to the control with G25 and G26
(working area limit). These working area limitations are activated with WALIMON and
deactivated again with WALIMOF. The working area limitation must be active at the instant
of path reversal.
Reference:
/BPN/ Operation and Programming, Nibbling
Effect
If the current offset angle is outside the active working area limit for the following axis, an
attempt is made to return to within the permissible working area by means of the negative
offset angle.
Programming example for direction reversal, principle
N10 TANG (C, X, Y)
; Definition of the tangential control
N20 TLIFT (C)
; Activate Insert intermediate block at corners
N30 G1 X10 Y0 F1000
N40 G25 C50
; Value of the lower working area limit
N50 G26 C70
; Value of the upper working area limit
N60 TANGON (C, 60)
; Switch on tangential control, offset angle 60 degrees