HEIDENHAIN TNC 320 User's Manual For Cycle Programming page 145

5
SLOT MILLING (Cycle 253, DIN/ISO: G253) 5.4
Q439 Feed rate reference (0-3)?: Specify what the
Q439=0 ;FEED RATE REFERENCE
programmed feed rate refers to:
9 L X+50 Y+50 R0 FMAX M3 M99
0: Feed rate with respect to the tool center point
path
1: Feed rate with respect to the tool edge, but only
during side finishing, otherwise with respect to the
tool center point path
2: Feed rate refers to the tool cutting edge during
side finishing and floor finishing; otherwise it refers
to the tool path center
3: Feed rate always refers to the cutting edge
145
HEIDENHAIN | TNC 320 | User's manual for cycle programming | 9/2016