2 rectangular pocket (cycle 251, din/iso: g251), Cycle run – HEIDENHAIN TNC 640 (34059x-01) Cycle programming User Manual
Page 129

HEIDENHAIN TNC 640
129
5.2 RECT
ANGULAR POCKET (Cy
c
le
251, DIN/ISO: G251)
5.2 RECTANGULAR POCKET
(Cycle 251, DIN/ISO: G251)
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 into 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 allowances 
(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 infeed 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.
