In Mold Pressure Sensing Architecture for Multi Cavity Tooling Setup
In-cavity piezoelectric pressure sensing setups in multi-cavity tools decouple fill control from hydraulic drift to minimize scrap and verify part density.
Cavity Pressure Monitoring
Meaning
Continuous measurement of the force exerted by molten polymer inside the mould cavity occurs during the injection, packing, and holding phases. Utilizing cavity pressure monitoring allows moulders to detect variations in viscosity and fill rate in real time. This system records the peak pressure to determine the consistency of the moulded parts.
Parameter Tracking
Transducers placed behind ejector pins or directly in the cavity record the pressure profile of each shot. This profile serves as a digital signature of the plastic behavior during the cycle. When the pressure falls below a set threshold, the part may have short shots or sink marks.
If the pressure exceeds the upper limit, flash is likely to occur.
Quality Assurance
Automated sorting gates use the pressure data to isolate defective parts immediately after ejection. This prevents bad parts from reaching the packaging area and reduces the need for manual inspection. In precision medical moulding, this technology ensures that only parts with the correct dimensions are shipped to the customer.
This level of control is impossible with machine-only monitoring and provides a continuous digital record of every single shot.
Implementation Obstacle
Installing transducers in existing moulds requires extensive machining and increases the initial tooling cost. The delicate cables and sensors must also be protected from the high temperatures and pressures of the moulding process. This high entry cost often restricts the technology to high-volume or high-risk applications.