Meaning
Continuous change over time in the baseline output signal of a transducer under constant environmental conditions defines this parameter. A high baseline drift rate in cavity pressure sensors leads to incorrect switchover points during injection moulding runs. The metric measures the rate of signal change per hour or per thousand cycles.
Sensor Degradation
Piezoelectric elements in cavity pressure sensors experience a loss of insulation resistance when exposed to elevated temperatures and cyclic loads. This degradation accelerates the baseline drift rate as moisture or ionic contaminants penetrate the sensor housing. Clean sensor maintenance prevents premature signal decay.
Process Influence
High mould temperatures and rapid cycle times intensify the thermal stresses that drive sensor drift. Moulders must run calibration cycles to reset the signal baseline between shots, which minimizes the accumulation of offset errors. When the baseline drift rate exceeds the tolerance of the control system, the part weight fluctuates because the cavity pressure measurements lose accuracy.
In long production runs, automated software algorithms subtract this drift to maintain a stable switchover point and protect the tool from overpressurization.
Defect Correlation
Inconsistent part dimensions and flash occur when the sensor signal shifts during a production run. Because the baseline drift rate alters the perceived pressure, the machine may delay the transition to the pack stage, filling the cavity with excess resin. Regular monitoring of this drift ensures stable component weight.
