Siemens sinumerik 840D sl Function Manual page 866

The shaft characteristics are not taken into account on any of the tool types. For this reason,
the two tool types 120 (end mill) and 155 (bevel cutter), for example, have an identical
machining action since only the section at the tool tip is taken into account. The only
difference between these tools is that the tool shape is represented differently (dimensions).
Figure 2-12
The tool data are stored under the following tool parameter numbers:
Table 2-2
Tool data
d
r
a
Note
The geometry and wear values of a tool data are added.
The reference point for tool length compensation (also referred to as tool tip or tool center
point (TCP)) on all tool types is the point at which the longitudinal axis of the tool penetrates
the surface.
A new tool with different dimensions may be programmed only when the tool compensation
is activated for the first time (i.e. on transition from G40 to G41 or G42) or, if the
compensation is already active, only when G41 or G42 are reprogrammed.
In contrast to circumferential milling, therefore, there are no variable tool dimensions in one
block.
This restriction applies only to the tool shape (tool type, dimensions d, r and a).
Special functions: 3D Tool Radius Compensation (W5)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
Tool types for face milling
Tool parameter numbers for tool data
Geometry
$TC_DP6
$TC_DP7
$TC_DP11
Detailed description
2.2 Face milling
Wear
$TC_DP15
$TC_DP16
$TC_DP20
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