Meaning
Sensor instrumentation utilizing quartz crystal elements converts dynamic mechanical forces into proportional electrical charge inside mold cavities. Installation of a piezoelectric pressure transducer measures melt front arrival, peak cavity pressure, and gate freeze timing directly behind core pins or cavity walls. Measurement capability stops when thermal limits of quartz elements are exceeded or when electrical charge leaks across insulation barriers during long hold cycles.
Technical datasheets detail sensor sensitivity and temperature ratings, guiding proper recessed installation inside hardened tool steel plates. Closed-loop process control systems use real-time pressure signals to switch press operation from fill to pack automatically.
Signal Generation
Applied mechanical pressure deforms synthetic quartz crystals, releasing electrical charges proportional to the force exerted by molten plastic. Charge amplifiers convert pico-coulomb signals into standard voltage outputs suitable for process controller acquisition.
Cavity Monitoring
Direct cavity sensing detects subtle melt viscosity changes, raw material lot variations, and nozzle temperature drifts during high speed production cycles. Real-time pressure curves enable automated part sorting by rejecting shots that drift outside established pressure boundaries.
Calibration Drift
High mold operating temperatures and mechanical pin friction induce signal drift over extended production campaigns. Routine recalibration against reference load cells maintains measurement accuracy across multi-cavity injection tooling setups.
