Tool Length Offsets In Tool Direction - Siemens SINUMERIK 840Di Function Manual

Detailed Description
2.8 Special handling of tool compensations
2.8.8

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.
Compensation applies to the "Temperature compensation" option and is active only when
the axis to be compensated is really referenced.
Activation
Temperature compensation in the tool direction is an option, which must be enabled
beforehand.
It is activated by setting machine data:
MD20390 $MC_TOOL_TEMP_COMP_ON
to a value other than zero.
Bit 2 must also be enabled in machine data:
MD32750 $MA_TEMP_COMP_TYPE[<axis index>]
for each affected channel axis.
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
Temperature compensation in the tool direction is operative only with generic 5-axis
transformations with:
• Transformation type 24
• Transformation type 56
2-122
Two axes rotate the tool
One axis rotates the tool, the other axis rotates the workpiece without temperature
compensation
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Tool Compensation (W1)