Siemens sinumerik 840D sl Operating Manual page 268

Programming technology functions (cycles)
8.1 Drilling
Parameters Description
D Maximum depth infeed
Percentage for each additional infeed
DF 
DF=100: Infeed increment remains constant
DF<100: Infeed increment is reduced in direction of final drilling depth Z1.
Example: last infeed 4 mm; DF 80%
next infeed = 4 x 80% = 3.2 mm
next but one infeed = 3.2 x 80% = 2.56 mm etc.
Amount for each additional infeed

V1 Minimum infeed - (only for DF, percentage for each additional infeed)
Parameter V1 is only available if DF< 100 has been programmed.
If the infeed increment becomes very small, a minimum infeed can be programmed in
parameter "V1".
V1 < Infeed increment: The tool is inserted by the infeed increment
V1 > Infeed increment: The tool is inserted by the infeed value programmed under V1.
Predrilling Predrilling with reduced feedrate
Yes

No

The reduced drilling feedrate is obtained as follows:
Drilling feedrate F1 < 0.15 mm/rev: Predrilling feedrate = 30% of F1
Drilling feedrate F1 ≥ 0.15 mm/rev: Predrilling feedrate = 0.1 mm/rev
AZ Predrilling depth with reduced drilling feedrate - ("yes", only for predrilling)
Through boring Remaining drilling depth with drilling feedrate
Yes

No

ZR Residual drilling depth for through boring - ("yes", only for through boring)
FR Drilling feedrate for remaining drilling depth - ("yes", only for through boring)
Stock removal Stock removal before thread milling
Yes

No

Return to workpiece surface for stock removal before thread milling.
Thread Direction of rotation of the thread
Righthand thread

Lefthand thread

F2 Feedrate for thread milling
Table Thread table selection:
without

ISO metric

Whitworth BSW

Whitworth BSP

UNC

268
Operating Manual, 07/2010, 6FC5398-8CP40-0BA0
Unit
%
mm
mm
mm
in/mm
in/rev
in/min
in/tooth
Turning