Renishaw HPGA, Installation And User Manual

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Calibrating the probe
The exact procedure adopted is specific to each machine, control system and software
package. However certain rules are common.
Before setting tools, it is necessary to calibrate the stylus position to establish its trigger
points in relation to a datum on the machine. This can be achieved by the use of a
known reference tool.
Recalibration is necessary periodically (at least every 6 months), and in special
circumstances e.g. if the arm has been subjected to a crash or if the stylus has been
replaced.
The recommended frequency of normal recalibration is dependent on the frequency
of usage of the arm. This may vary greatly depending on the application of the tool
setting arm, i.e. a typical jobbing shop may want to set tools twice per day and have
8 tools to set. This would therefore result in 2 arm operations per day. A large volume
manufacturer however, may only wish to check for broken tools, but with a typical cycle
time of 5 minutes and 24 hour working days, would operate the arm 288 times per day.
The following table should therefore be used when deciding on frequency of
recalibration:
Calibration
Recommended frequency of arm recalibration
Arms operations per day Recalibrate every...
<50 6 months
<100 3 months
>100 1 month