Siemens SINUMERIK 840C Installation Instructions Manual page 844

06.93
Example for thread on a cylindrical workpiece:
N10 ...
N20 G0 C30 Z2
N30 G36 C Z-30 K5 F1000
N40 C Z2 K-2
.
.
Explanation:
In block N30 the rotary axis must be written with G36 (spindle as axis). A value written behind
C is ignored.
To simplify programming, the final point of the rotary axis is not programmed. The control
derives the final point from the programmed lead and the path of the linear axis.
The thread lead is programmed under address K (I, J). The sign in front of K shows the
direction of rotation (see example above). Clockwise/counterclockwise movement is defined in
the Programming Guide in the section Coordinate systems.
A lead must be assigned to the individual axes with G36 as well as with G33, G34, G35. The
assignment is stored in MD 304*.
Thread lead 0 or a programmed address where axis and thread lead do not harmonize, triggers
alarm 3006 "Wrong block structure".
At least 2 axes, of which one is a rotary axis, must be programmed, otherwise alarm 3006
"Wrong block structure" is triggered.
G98 is triggered internally with G36, i.e. the programmed feedrate F refers only to the rotary
axis in rev/min.
The resulting path feedrate (C axis and linear axis) is derived internally from the programmed
lead.
The rotary axis (in this case C axis) must be written in every block with G36 active (N30/N40).
Starting conditions at block transfers can be influenced with G60 or G64.
Example for thread on a tapered workpiece:
N10 ...
N20 G0 C30 X10 Z2
N30 G36 C Z-30 X20 K5
.
.
.
Explanation:
In block N30 the rotary axis must be written with G36 (spindle as axis). A value written behind
C is ignored.
To simplify programming, the final point of the rotary axis is not programmed. The control
derives the final point from the programmed lead and the path of the linear axis.
© Siemens AG 1992 All Rights Reserved
SINUMERIK 840C (IA)
(Switch spindle to rotary axis mode)
(Position rotary axis to 30 degrees, position
Z = 2 mm; corresponds to thread insertion point)
(Thread lead 5 mm/revolution, clockwise; feedrate of C
axis 1000 rev/min)
(Thread lead 5 mm/revolution, counter-clockwise,
feedrate of C axis 1000 rev/min)
(Switch spindle to axis mode)
(Position rotary axis to 30 degrees, position
Z = 2 mm, X = 10 mm; corresponds to the thread
insertion point)
(Thread lead 5 mm/revolution, clockwise;
F1000
Feedrate of C axis 1000 rev/min)
6FC5197- AA50
12 Functional Descriptions
12.9.2 Description of function
12–69