HEIDENHAIN iTNC 530 (340 420) ISO programming - Manual (Page 258)

258 8 Programming: Cycles
8.3 Cy
cles f
o
r Dr
illing, T
a
pping and Thr
ead Milling
U U U U Set-up clearance Q200 (incremental value): Distance
between tool tip and workpiece surface.
U U U U Workpiece surface coordinate Q203 (absolute
value): Coordinate of the workpiece surface.
U U U U 2nd set-up clearance Q204 (incremental value):
Coordinate in the tool axis at which no collision
between tool and workpiece (clamping devices) can
occur.
U U U U Feed rate for plunging Q206: Traversing speed of
the tool during drilling in mm/min.
U U U U Feed rate for milling Q207: Traversing speed of the
tool in mm/min while milling.
HELICAL THREAD DRILLING/MILLING
(Cycle G265)
1 The TNC positions the tool in the tool axis at rapid traverse to the
programmed set-up clearance above the workpiece surface.
Countersinking at front
2 If countersinking is before thread milling, the tool moves at the
feed rate for countersinking to the sinking depth at front. If
countersinking is after thread milling, the tool moves at the feed
rate for pre-positioning to the countersinking depth.
3 The TNC positions the tool without compensation from the center
on a semicircle to the offset at front, and then follows a circular
path at the feed rate for countersinking.
4 The tool then moves on a semicircle to the hole center.
Thread milling
5 The tool moves at the programmed feed rate for pre-positioning to
the starting plane for the thread.
6 The tool then approaches the thread diameter tangentially in a
helical movement.
7 The tool moves on a continuous helical downward path until it
reaches the thread depth.
8 After this, the tool departs the contour tangentially and returns to
the starting point in the working plane.
Example: NC blocks
N250 G264 THREAD DRILLING/MILLING
Q335=10 ;NOMINAL DIAMETER
Q239=+1.5 ;PITCH
Q201=-16 ;THREAD DEPTH
Q356=-20 ;TOTAL HOLE DEPTH
Q253=750 ;F PRE-POSITIONING
Q351=+1 ;CLIMB OR UP-CUT
Q202=5 ;PLUNGING DEPTH
Q258=0.2 ;ADVANCED STOP DISTANCE
Q257=5 ;DEPTH FOR CHIP BRKNG
Q256=0.2 ;DIST. FOR CHIP BRKNG
Q358=+0 ;DEPTH AT FRONT
Q359=+0 ;OFFSET AT FRONT
Q200=2 ;SET-UP CLEARANCE
Q203=+30 ;SURFACE COORDINATE
Q204=50 ;2ND SET-UP CLEARANCE
Q206=150 ;FEED RATE FOR PLUNGING
Q207=500 ;FEED RATE FOR MILLING