Siemens SINUMERIK 808D User Manual page 172

Se quence of operations
Ta pping with compensating chuck with encoder
Position reached prior to cycle start:
The drilling position is the position in the two axes of the selected plane.
The cycle creates the following sequence of motions:
● Approach of the reference plane brought forward by the safety clearance by using G0
● Tapping to the final drilling depth
● Dwell time at thread depth (parameter DTB)
● Retraction to the reference plane brought forward by the safety clearance
● Retraction to the retraction plane with G0
Explanation of the parameters
For more information about the parameters RTP, RFP, SDIS, DP, DPR, see Section "Drilling, centering - CYCLE81
(Page 157)".
D TB (dwell time)
The dwell time must be programmed in seconds.
SD R (direction of rotation for retraction)
SDR=0 must be set if the spindle direction is to reverse automatically.
If the machine data is defined such that no encoder is set (in this case, machine data MD30200 $MA_NUM_ENCS is 0), the
parameter must be assigned the value 3 or 4 for the direction of rotation; otherwise, alarm 61202 "No spindle direction
programmed" is output and the cycle is aborted.
SD AC (direction of rotation)
Because the cycle can also be called modally (see Section "Graphical cycle programming in the program editor
(Page 154)"), it requires a direction of rotation for tapping further threaded holes. This is programmed in parameter SDAC
and corresponds to the direction of rotation programmed before the first call in the higher-level program. If SDR=0, the value
assigned to SDAC has no meaning in the cycle and can be omitted in the parameterization.
EN C (tapping)
If tapping is to be performed without encoder although an encoder exists, parameter ENC must be assigned value 1.
If, however, no encoder is installed and the parameter is assigned the value 0, it is ignored in the cycle.
MPIT and PIT (thread lead as a thread size and as a value)
The parameter for the lead is only relevant if tapping is performed with encoder. The cycle calculates the feedrate from the
spindle speed and the lead.
Programming and Operating Manual (Milling)
172
6FC5398-4DP10-0BA6, 09/2017