HEIDENHAIN iTNC 530 (340 420) ISO programming - Manual (Page 261)

HEIDENHAIN iTNC 530 261
8.3 Cy
cles f
o
r Dr
illing, T
a
pping and Thr
ead Milling
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 counterboring Q254: Traversing
speed of the tool during counterboring in mm/min.
U U U U Feed rate for milling Q207: Traversing speed of the
tool in mm/min while milling.
OUTSIDE THREAD MILLING (Cycle G267)
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 The TNC moves in the reference axis of the working plane from
the center of the stud to the starting point for countersinking at
front. The position of the starting point is determined by the thread
radius, tool radius and pitch.
3 The tool moves at the feed rate for pre-positioning to the sinking
depth at front.
4 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.
5 The tool then moves on a semicircle to the starting point.
Thread milling
6 The TNC positions the tool to the starting point if there has been
no previous countersinking at front. Starting point for thread milling
= starting point for countersinking at front.
7 The tool moves at the programmed feed rate for pre-positioning to
the starting plane. The starting plane is derived from the algebraic
sign of the thread pitch, the milling method (climb or up-cut milling)
and the number of threads per step.
8 The tool then approaches the thread diameter tangentially in a
helical movement.
9 Depending on the setting of the parameter for the number of
threads, the tool mills the thread in one helical movement, in
several offset movements or in one continuous movement.
10 After this, the tool departs the contour tangentially and returns to
the starting point in the working plane.
Example: NC blocks
N250 G265 HEL. THREAD DRLG/MLG
Q335=10 ;NOMINAL DIAMETER
Q239=+1.5 ;PITCH
Q201=-16 ;THREAD DEPTH
Q253=750 ;F PRE-POSITIONING
Q358=+0 ;DEPTH AT FRONT
Q359=+0 ;OFFSET AT FRONT
Q360=0 ;COUNTERSINKING
Q200=2 ;SET-UP CLEARANCE
Q203=+30 ;SURFACE COORDINATE
Q204=50 ;2ND SET-UP CLEARANCE
Q254=150 ;F COUNTERBORING
Q207=500 ;FEED RATE FOR MILLING