HEIDENHAIN TNC 407 (280 580) User Manual User Manual

Page 161

TNC 425/TNC 415 B/TNC 407

5-62

Programming Tool Movements

Fig. 5.52:

Contouring behavior at R0 with
M90

Fig. 5.51:

Standard contouring behavior at
R0 without M90

5.7 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 between straight lines at non-tangential transi-

tions

• Machining small contour steps
• Machining open contour corners
• Entering machine-referenced coordinates

Smoothing corners: M90

Standard behavior – without M90

At angular transitions such as internal corners and contours with R0, the
TNC stops the axes briefly.

Advantages:

• Reduces wear on the machine
• High definition of corners (outside)

Note:

In program blocks with radius compensation (RR/RL) at external corners
the TNC automatically inserts a transition arc.

Smoothing corners with M90

The tool moves at corners with constant speed.

Advantages:

• Provides a smoother, more continuous surface
• Reduced machining time

Example application:
Surfaces consisting of several straight line segments.

Duration of effect

The miscellaneous function M90 is effective only in
the blocks in which it is programmed. Operation
with servo lag must be active.

A limit value can be set in machine parameter MP7460 (see page
12-12) below which the tool will move at constant feed rate (valid for
operation both with servo lag and with feed precontrol). This value is
valid regardless of M90.