Masking Out External Tolerances; Evaluation Criteria - HBM MP85A Operating Manual

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6.4 Masking out external tolerances

The MP85A process controller can suppress external tolerances, such as
those caused by the differing positioning heights of workpiece holders, e.g.
when the pin being press-fitted is touched. Displacement is set to zero at this
time and a second relative axis is drawn to which the coordinates of the evalu-
ation elements now refer.
Fig. 6.4: Reference points for X relative reference of evaluation elements

6.5 Evaluation criteria

The MP85A process controller has different window types to allow a universal
evaluation of the various curve shapes using window techniques. Any mix of
these window types can be used for each measurement curve. An envelope
curve is available if the entire process is to be monitored without a gap.
Fig. 6.5: Evaluation method using tolerance windows
Thread-in window
This checks that the fitting partners thread in correctly and do not fit askew.
A real-time signal indicates that there is a thread-in problem (for example,
window exited at top) and this can be used by the press control to trigger the
return stroke of the press, for example.
HBM
Reference point
Dynamic zero point, relative to the force trigger.
When the reference point is reached, displacement is set
to zero. The windows now relate to this zero point.
MP85A process controller
A2392−5.0 en