Siemens SINUMERIK 840D SL Operating Manual page 347

Machining type, roughing plunge cutting
Roughing of the slot takes place sequentially along the length of the groove, with the milling
cutter performing vertical insertions at the machining feedrate. The milling cutter is then
retracted and repositioned at the next insertion point.
The milling cutter moves along the length of the slot, at half the infeed rate, and inserts
alternately at the left-hand and right-hand walls.
The first insertion motion takes place at the slot edge, with the milling cutter inserted at half
the infeed, less the safety clearance. (if the safety clearance is greater than the infeed, this
will be on the outside). For this cycle, the maximum width of the slot must be less than
double the width of the milling cutter + the finishing allowance.
Following each insertion, the milling cutter is lifted by the height of the safety clearance at the
machining feedrate. As far as possible, this occurs during what is known as the retraction
process, i.e. if the milling cutter's wrap angle is less than 180°, it is lifted at a 45- angle from
the base in the opposite direction to the bisector of the wrap area.
The milling cutter then traverses over the material in rapid traverse.
Supplementary conditions for plunge cutting
● Roughing
● Maximum radial infeed
● Increment
● Retraction
Milling
Operating Manual, 02/2012, 6FC5398-7CP40-3BA0
1/2 slot width W - finishing allowance UXY ≤ milling cutter diameter
The maximum infeed depends on the cutting edge width of the milling cutter.
The lateral increment is calculated on the basis of the required slot width, milling cutter
diameter and finishing allowance.
Retraction involves the milling cutter being retracted at a 45° angle if the wrap angle is
less than 180°. Otherwise, retraction is perpendicular, as is the case with drilling.
Programming technological functions (cycles)
8.2 Milling
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