Siemens SINUMERIK 840D Programming Manual page 306

4 4
Turning Cycles 03.96
09.01
4.6 Thread undercut – CYCLE96
FORM (definition)
Thread undercuts of forms A and B are defined for FORM A and B
external threads, form A for normal thread run-outs,
SPL
30°
form B for short thread run-outs.
DIATH
Thread undercuts of forms C and D for used for
internal threads, form C for normal thread runouts,
form D for short thread run-outs.
If the parameter is assigned a value other than
A ... D, the cycle is aborted and alarm
61609 "Form incorrectly defined" is output.
The tool radius compensation is automatically
selected by the cycle.
_VARI (undercut position)
The position of the undercut can be either specified
directly or derived from the tool point direction with
parameter _VARI.
FORM C and D
See _VARI with CYCLE94
SPL
The cycle automatically determines the starting point
that is defined by the tool point direction of the active
DIATH
tool and the thread diameter. The position of this
starting point in relation to the programmed
coordinate values is determined by the tool point
position of the active tool.
30°
The cycle monitors the clearance angle of the active
tool if forms A and B are being machined. If the cycle
detects that the undercut form cannot be machined
with the selected tool, the message
"Changed undercut form"
is output by the control but machining is continued.
© Siemens AG, 2002. All rights reserved
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SINUMERIK 840D/840Di/810D Programming Guide Cycles (PGZ) – 11.02 Edition