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.
Triboelectric Cable Noise
Meaning
Electrical interference arises from friction within sensor wiring. Technicians encounter triboelectric cable noise when cables between a pressure sensor and an amplifier flex during a machine cycle. This friction generates a parasitic charge that obscures the true signal from the mould cavity.
It is a common problem in moving mould components like slides or ejector plates.
Charge Induction
Mechanical movement causes the different layers of the cable to rub together. The resulting static electricity is indistinguishable from the signal produced by the sensor. Triboelectric cable noise appears as random spikes or waves on the pressure curve.
Signal Integrity
Accuracy of the data is compromised when the noise level is high. The control system may interpret a noise spike as a pressure peak and prematurely stop the injection. This leads to inconsistent part quality and frequent process alarms.
Cable Selection
Specialized low noise cables are used to mitigate this effect. These cables include a conductive lubricant or a graphite layer between the dielectric and the shield to bleed off the static charge. Routing the cables through rigid conduits also helps by reducing the amount of physical flexing.
Correct cable management is the primary defense against this type of signal distortion.