Tool Length Offsets In Tool Direction - Siemens SINUMERIK 840D sl Function Manual

W1: Tool offset
2.14 Special handling of tool offsets
2.14.5

Tool length offsets in tool direction

Temperature compensation in real time
On 5-axis machines with a moving tool, temperature fluctuations can occur in the machining
heads. These can result directly in expansion fluctuations which are transmitted to the tool
spindle in the form of linear expansion. A typical case on 5-axis heads, for example, is thermal
expansion in the direction of the longitudinal spindle axis.
It is possible to compensate this thermal expansion even when the tool is orientated by
assigning the temperature compensation values to the tool rather than to the machine axes. In
this way, linear expansion fluctuations can be compensated even when the tool orientation
changes.
Using the orientation transformation whose direction is determined by the current tool
orientation, it is possible to overlay motions in real time and rotate them simultaneously. At the
same time, the compensation values are adjusted continuously in the tool coordinate system.
The temperature compensation only becomes effective if the axis to be compensated is really
referenced.
Activation
The temperature compensation in the tool direction is activated by setting the following
machine data to a value not equal to zero.
MD20390 $MC_TOOL_TEMP_COMP_ON (activation of temperature compensation for tool
length)
In addition, bit 2 must be set for each affected channel axis in the machine data:
MD32750 $MA_TEMP_COMP_TYPE [<axis index>] (temperature compensation type)
This can be more than three axes in cases where more than three channel axes in succession
can be temporarily assigned to geometry axes as a result of geometry axis replacement of
transformation switchover. If this bit is not set for a particular channel axis, the compensation
value cannot be applied in the axis. This does not have any effect on other axes. In this case,
an alarm is not output.
Applicability
The temperature compensation in the tool direction is only effective with generic 5-axis
transformations with:
● Transformation type 24
Two axes rotate the tool
● Transformation type 56
One axis rotates the tool, the other axis rotates the workpiece without temperature
compensation
In generic 5-axis transformation with:
● Transformation type 40
The tool orientation is constant with a rotary workpiece, which means that the motion of the
rotary axes on the machine does not affect the temperature compensation direction.
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Function Manual, 06/2019, A5E47435126B AA
Tools