Siemens SINUMERIK 840Di Function Manual page 150

Detailed Description
2.2 Exact stop
Consequences
If a block change cannot be executed in continuous-path mode, all axes programmed in this
part program block (except modal special axes) are stopped. In this case, contour errors do
not occur. The stopping of the path axes during machining can cause undercuts on the
workpiece surface.
2.2 Exact stop
2.2
Exact stop or exact stop mode
In contrast to continuous-path mode, in exact stop or exact stop mode, all path axes and
non-modal special axes involved in the traversing motion are decelerated until they reach a
standstill at the end of each block. The transition to the next block occurs only when all axes
involved in the traversing motion have reached their programmed target position with subject
to the selected exact stop criterion.
This results in the following response:
• All path axes and non-modal special axes involved in the traversing motion are
• The program run time is considerably longer compared to continuous-path mode due to
• In exact stop mode, undercuts can occur on the workpiece surface during machining.
Use
Exact stop mode should always be used when the programmed contour must be executed
exactly.
Activation of exact stop mode
Exact stop mode is activated in the part program by programming the following G-functions:
• G60 - Exact stop on, modal
• G09 - Exact stop on, non-modal
Exact stop criteria: "Exact stop coarse" and "Exact stop fine"
The two exact stop criteria "Exact stop coarse" and "Exact stop fine" are used to specify the
applicable tolerance window for reaching the "Exact stop" state of a machine.
2-2
decelerated at the end of the block until they reach a standstill.
the deceleration of the axes and the wait time until "Exact stop" status is reached for all
machine axes involved.
Continuous-Path Mode, Exact Stop, LookAhead (B1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0