HEIDENHAIN TNC 620 (34056x-04) Cycle programming - Manual (Page 131)

RECTANGULAR POCKET (Cycle 251, DIN/ISO: G251, software
option 19)
5.2
5
TNC 620 | User's Manual Cycle Programming | 5/2013
131
5.2 RECTANGULAR POCKET (Cycle 251,
DIN/ISO: G251, software option 19)
Cycle run
Use Cycle 251 RECTANGULAR POCKET to completely machine
rectangular pockets. Depending on the cycle parameters, the
following machining alternatives are available:
Complete machining: Roughing, floor finishing, side finishing
Only roughing
Only floor finishing and side finishing
Only floor finishing
Only side finishing
Roughing
1 The tool plunges the workpiece at the pocket center and
advances to the first plunging depth. Specify the plunging
strategy with parameter Q366.
2 The TNC roughs out the pocket from the inside out, taking the
overlap factor (Parameter Q370) and the finishing allowance
(Parameters Q368 and Q369) into account.
3 At the end of the roughing operation, the TNC moves the tool
tangentially away from the pocket wall, then moves by the set-
up clearance above the current pecking depth and returns from
there at rapid traverse to the pocket center.
4 This process is repeated until the programmed pocket depth is
reached.
Finishing
5 Inasmuch as finishing allowances are defined, the TNC then
finishes the pocket walls, in multiple infeeds if so specified. The
pocket wall is approached tangentially.
6 Then the TNC finishes the floor of the pocket from the inside
out. The pocket floor is approached tangentially.