Siemens SINUMERIK 840D Programming Manual page 241

03.96
4
FORM (definition)
Thread undercuts of forms A and B are defined for
external threads, form A for normal thread runouts,
form B for short thread runouts.
Thread undercuts of forms C and D for used for
internal threads, form C for normal thread run-outs,
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.
The cycle only operates with tool point directions
1 ... 4. If the cycle recognizes a tool point direction 5
... 9 or if it is not possible to machine the undercut
form with the selected tool point direction, alarm
61608 "Wrong tool point direction programmed"
is output and the cycle is aborted.
The cycle automatically determines the starting point
that is defined by the tool point direction of the active
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.
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 2000 All rights reserved.
SINUMERIK 840D/840Di/810D/FM-NC Programming Guide, Cycles (PGZ) - 04.00 Edition
4.6 Thread undercut – CYCLE96
FORM A and B
SPL
FORM C and D
SPL
R
R
Turning Cycles
4
R
30°
R
DIATH
DIATH
30°
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