HEIDENHAIN CNC Pilot 4290 V7.1 - Manual (Page 196)

196
4.15 T
ool-Tip and Cut
ter Radius Compensation
4.15 Tool-Tip and Cutter Radius
Compensation
Tool-tip radius compensation (TRC)
If TRC is not used, the theoretical tool tip is the reference point for the
paths of traverse. This might lead to inaccuracies when the tool moves
along non-paraxial paths of traverse. The TRC function corrects
programmed paths of traverse.
The TRC (Q=0) reduces the feed rate for circular arcs if the shifted
radius < the original radius. The TRC corrects the special feed rate
when a rounding arc is machined as transition to the next contour
element.
Reduced feed rate = feed rate * (shifted radius / original radius)
Milling cutter radius compensation (MCRC)
When the MCRC function is not active, the system defines the center
of the cutter as the zero point for the paths of traverse. With the CNC
PILOT accounts for the outside cutting radius when moving along the
programmed paths of traverse. The recessing, roughing and milling
cycles already include TRC/MCRC calls. The TRC/MCRC must be
switched off when these cycles are called.
„ If the tool radii are > than the contour radii, the TRC/
MCRC might cause endless loops. Recommendation:
Use the finishing cycle G890 or milling cycle G840.
„ Never program the MCRC during a perpendicular
approach to the machining plane.
„ Note on calling subprograms: Switch the TRC/MCRC off
„ in the subprogram in which it was switched on.
„ in the main program if it was switched on there.