Cavity Pressure Telemetry Fundamentals in Fast-Cycle Moulding
Cavity pressure telemetry decouples fast-cycle moulding from resin viscosity shifts by driving switchover directly from real-time in-cavity melt fronts.
Picocoulombs per Bar
Meaning
Sensitivity ratings define the electrical output generated for every unit of physical pressure applied. The term picocoulombs per bar describes the gain of a piezoelectric pressure sensor. A higher value means the sensor produces a stronger signal for the same amount of melt pressure.
This value is used to calibrate the charge amplifier so the controller displays the correct pressure in bars or psi.
Calibration Sensitivity
Every sensor is shipped with a unique certificate stating its exact output. The value of picocoulombs per bar is programmed into the monitoring system before the first shot. This ensures that the digital reading matches the physical reality inside the mould.
Signal Resolution
Small changes in pressure are easier to detect when the sensor has a high sensitivity. Sensors with low picocoulombs per bar ratings may struggle to provide clear data in low pressure applications like thin wall moulding. Choosing the right sensitivity is essential for capturing the details of the packing phase.
System Selection
Matching the sensor to the expected pressure range prevents signal clipping or excessive noise. If the sensitivity is too high, the amplifier might saturate at maximum pressure. If it is too low, the signal might be lost in the electronic background noise.
Proper selection based on the picocoulombs per bar rating ensures a reliable process window.