Convex Thread (G335, G336) - Siemens SINUMERIK 840D sl Programming Manual

Fundamentals
2.9 Motion commands
Program code
N20 G0 G90 X170
N22 POLF[X]=210 LFPOS
N23 POLFMASK(X)
N25 G33 X100 I10 LFON
N30 X135 Z-45 K10
N40 X155 Z-128 K10
N50 X145 Z-168 K10
N55 X210 I10
N60 G0 Z0 LFOF
N70 POLFMASK()
M30
2.9.10.5

Convex thread (G335, G336)

The G commands G335 and G336 can be used to turn convex threads (= differing to the
cylindrical form). Application is the machining of extremely large components that sag in the
machine because of their self-weight. Paraxial thread would result in the thread being too small
in the middle of the component. This can be compensated with convex threads.
Figure 2-6
Programming
The turning of a convex thread is programmed with G335 or G336:
G335:
G336:
The programming is performed first as for a linear thread by specifying the axial block end
points and the pitch via parameters I, J and K (see "Thread cutting with constant lead (G33, SF)
(Page 221)").
An arc is also specified. As for G2/G3, this can be programmed via the center point, radius,
opening angle or intermediate point specification (see "Circular interpolation (Page 188)").
When programming the convex thread with center point programming, the following must be
taken into account: Since I, J and K are used for the pitch in thread cutting, the circle
234
Turning a convex thread
Turning of a convex thread on a circular tool path in a clockwise direction
Turning of a convex thread on a circular tool path in a counter-clockwise direction
Comment
; Activate (enable) rapid retraction from axis X.
; Disable lift for all axes.
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming