HEIDENHAIN TNC 407 (280 580) ISO Programming - Manual (Page 169)

TNC 426/TNC 425/TNC 415 B/TNC 407 5 - 3 6
5 Programming Tool Movements
5.6 M Functions for Contouring Behavior and Coordinate Data
The following miscellaneous functions enable you to change the TNC's
standard contouring behavior in certain situations:
• Smoothing corners
• Inserting rounding arcs at non-tangential straight-line transitions
• Machining small contour steps
• Machining open contours
• Programming machine-referenced coordinates
Smoothing corners: M90
Standard behavior – without M90
The TNC stops the axes briefly at sharp transitions such as inside corners
and contours without radius compensation.
Advantages:
• Reduced wear on the machine
• High definition of corners (outside)
Note:
In program blocks with radius compensation (G41/G42), the TNC
automatically inserts a transition arc at outside corners.
Smoothing corners with M90
At corners, the tool moves at constant speed. Advantages:
• A smoother, more continuous surface
• Reduced machining time
Example application:
Surface consisting of a series of straight line segments.
Duration of effect
Servo lag mode must be selected. M90 is only effective in the blocks in
which it is programmed.
Independently of M90, you can use machine parameter MP7460 to set
a limit value up to which the tool moves at constant path speed
(effective with servo lag and feed precontrol). See page 11-14.
G40
G40
Fig. 5.42: Standard contouring behavior at
G40 without M90
Fig. 5.43: Behavior at G40 with M90