Siemens Sinumerik 840D sl Programming Manual page 345

Singular positions
Note
ORIWKS
Orientation movements in the singular setting area of the 5-axis machine require vast
movements of the machine axes. (For example, with a rotary swivel head with C as the rotary
axis and A as the swivel axis, all positions with A = 0 are singular.)
Machine manufacturer
To avoid overloading the machine axes, the velocity control vastly reduces the tool path
velocity near the singular positions.
With machine data
$MC_TRAFO5_NON_POLE_LIMIT
$MC_TRAFO5_POLE_LIMIT
the transformation can be parameterized in such a way that orientation movements close to
the pole are put through the pole and rapid machining is possible.
Singular positions are handled only with the MD $MC_TRAFO5_POLE_LIMIT.
References:
/FB3/ Function Manual, Special Functions; 3- to 5-Axis Transformation (F2),
"Singular Points and How to Deal with Them" section.
Job planning
Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
6.2 Three, four and five axis transformation (TRAORI)
Transformations
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