118
12.1.6 Friction Value Package (optional)
12.1.6.1 Friction Value Measurement
The function of the screwdriving Strategy is the tightening of a screw, while considering the
friction value prior to screw head contact with the mating surface. The calculated friction
value is applied as a factor to the preset torque value
Figure 112:
Friction Value Measurement
Shut-off criteria:
The measuring process is ended once the
• end of the measuring range is achieved
• a calculated (variable) shut-off torque value is determined (based upon the friction
value)
• the maximum screwdriving time (time monitoring) is exceeded
Analysis:
OK evaluation:
The screwdriving sequence is considered OK (fault free), if the shut-off torque
value is determined based upon the friction value and the final torque value
achieved is within the preset limits.
Not OK analysis:
The screwdriving sequence is evaluated as Not OK (faulty), if the friction torque
in the monitored angle window is outside the preset limits or the determined
friction torque value is outside the preset limits.
The screwdriving level is also evaluated as Not OK when the maximum time
limit is exceeded.
