High Temperature Transducer Housing Design and Preload Calculations
Calculate stack thermal expansion divergence, introduce Inconel X-750 disc springs to boost compliance, and torque fasteners with boron nitride lubrication.
Curie Point
Meaning
The specific temperature boundary at which a ferromagnetic or piezoelectric material loses its permanent magnetic or electric properties defines the safe limit for mould cavity pressure sensors. For piezoelectric crystals used in these transducers, exceeding the curie point causes complete loss of signal. Sensitiveness is destroyed as the crystalline structure transitions to a symmetric, non-polar phase.
Sensor Selection
Cavity pressure transducers are placed directly in the flow path of molten polymers. Choosing a sensor with a high curie point ensures that the transducer remains operational during the high-temperature moulding of engineering plastics such as polyetheretherketone. Sensors must run cooler than this threshold to prevent measurement errors.
Moulding Temperature
Melt temperatures during injection moulding can exceed three hundred degrees Celsius. High mould and melt temperatures heat the sensor housing through direct conduction and convection. Transducers based on quartz can operate at higher temperatures because their curie point sits well above the limits of standard lead zirconate titanate ceramics.
Utilizing sensors with a high thermal threshold prevents thermal damage during long production runs of high-melting-point materials. It also eliminates the need for complex cooling systems.
Calibration Drift
Incomplete depolarization occurs when sensors are exposed to temperatures close to their thermal limit. This changes the sensor sensitivity. Transducers require recalibration.