Siemens SINUMERIK 840D Operating Manual page 230

Creating a ShopMill program
7.7 Tool, offset value, feed and spindle speed (T, D, F, S, V)
Tool length compensation
Tool length compensation takes effect as soon as the tool is loaded into the spindle.
Different tool offsets can be assigned to each tool with multiple cutting edges.
The tool length compensation of the spindle tool remains active even after the program has
been executed (RESET).
Radius compensation
The tool radius compensation is automatically included in the machining cycles except for
path milling.
For path milling and straight line/circle, you have the option of programming the machining
with or without radius compensation. The tool radius compensation is modal for straight
lines/circles, i.e. you have to deselect the radius compensation if you want to traverse
without radius compensation.
Feedrate (F)
The feedrate F (also referred to as the machining feedrate) specifies the speed at which the
tool moves when machining the workpiece. The machining feedrate is entered in mm/min,
mm/rev or in mm/tooth. The feedrate for milling cycles is automatically converted when
switching from mm/min to mm/rev and vice versa.
It is only possible to enter the feedrate in mm/tooth during milling; this ensures that each
cutting edge of the milling cutter is cutting under the best possible conditions. The feedrate
per tooth corresponds to the linear path traversed by the milling cutter when a tooth is
engaged.
With milling cycles, the feedrate for rough cutting is relative to the milling tool center point.
This also applies to finish cutting, with the exception of concave curves where the feedrate is
relative to the contact point between the tool and workpiece.
The maximum feedrate is determined via machine data.
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Radius compensation to right of contour
Radius compensation to left of contour
Radius compensation off
Radius compensation remains as previously set
Operating Manual, 03/2010, 6FC5398-7CP20-1BA0
Milling