Meaning
Presenting as a gradual shift in charge output within dynamic pressure sensing systems, signal baseline offset degrades cavity pressure monitoring accuracy over extended moulding cycles. Continuous thermal expansion and mechanical stress relaxation inside transducer housings cause piezoelectric drift in in-mould pressure sensors. As the charge output strays from calibrated zero points, automated press controls miscalculate cavity pack and hold timing.
Moulding processes using peak cavity pressure to trigger switchover suffer from part weight variation and sink marks when signal drift goes uncompensated. Charge amplifier reset routines between injection cycles help eliminate accumulated signal offset.
Charge Degradation
Thermal stress alters crystal lattice spacing within quartz or ceramic sensor elements during hot moulding cycles. Charge leakage across internal insulation layers reduces signal amplitude during long hold phases. Mechanical pre-load relaxation shifts the baseline voltage reference.
Process Instability
Displaced pressure signals trigger automatic V/P switchover at incorrect fill volumes. Early switchover causes short shots and poor surface finish. Late switchover overpacks the cavity, causing tool flashing and part sticking on ejection.
Amplifier Compensation
Digital charge amplifiers clear baseline drift by shorting the input circuit to ground between moulding cycles. Automatic reset routines ensure each injection cycle begins with a true zero-pressure reading.
