Siemens SINUMERIK 828D Operating Manual page 314

Programming technology functions (cycles)
9.1 Drilling
Direction of spindle rotation
The direction of rotation of the spindle, with which the tool enters and withdraws from the
pilot hole can be programmed as follows:
● with stationary spindle
● with clockwise rotating spindle
● with counterclockwise rotating spindle
This avoids long or thin drills from being broken.
Horizontal drilling
For horizontal drilling using spiral drills, entering the pilot hole is improved if the cutting
edges of the drill are also in the horizontal position. To support this, the alignment of the drill
in the spindle can be programmed for a specific position (SPOS).
The feedrate is stopped before reaching the pilot hole depth, the speed increased to the
drilling speed and the coolant switched in.
Soft first cut into the material
The entry into the material can be influenced, depending on the tool and the material.
● The predrilling feed rate is maintained to a programmable first feed distance.
● An additional programmable feed distance is used to continuously increase the feedrate
(with FLIN) to the drilling feed rate.
● For chip breaking/swarf removal, this mechanism is effective at each first cut. This means
that when removing swarf, no clearance distance (V3) applies – and for chip breaking, the
retraction distance is not effective (V2). These parameters are not displayed in the screen
form. In these cases, the depth (ZS1) of the soft first cut is effective as "clearance
distance" or as "retraction amount".
Deep-hole drilling at the exit from the hole
It makes sense to reduce the feedrate when for through drilling the exit is inclined with
respect to the tool axis.
● Through drilling "no"
The machining feedrate is used when drilling to the final drilling depth. You then have the
option of programming a dwell time at the drilling depth.
● Through drilling "yes"
Up to the remaining drilling depth, program drilling with the drilling feedrate; from that
point onwards, with a reduced feedrate.
The feedrate is not stopped, instead FLIN is employed (linear feed rate) in order to
prevent the drill motion from being excited.
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Operating Manual, 01/2015, 6FC5398-8CP40-5BA2
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