Kistler Instruments has produced a combined pressure and temperature sensor specifically to support automated resin transfer (RTM) and wet moulding composite manufacturing methods.
The new Type 4001A sensor has been developed to facilitate the growing use of composites in industries such as automotive, where large quantities of smaller components are required to be produced cost effectively.
The low pressure composite moulding techniques used for high volume composite production demand monitoring and control similar to conventional injection moulding to ensure consistent, high quality output.
Kistler says much like injection moulding and other filling processes, the cavity pressure curve is a key factor in process optimisation and production monitoring. Using the Type 4001A sensor, characteristic process phases such as evacuation, filling and curing can easily be identified from the pressure curve allowing process parameters to be easily optimised to make production more cost-effective.
The pressure signal can also be used as a control variable for individual process steps for online process control. Anomalies in the pressure curve show whether defects can be expected in the final part which, if out of tolerance, can be ejected. The pressure signal is also captured and recorded to allow traceability of individual process steps.
For these reasons, the pressure curve is an essential tool for quality assurance. Due to the much lower cavity pressure experienced in composite moulding systems, the cavity pressure sensor needs to measure low pressure with high resolution to reliably detect even the smallest pressure or vacuum changes.
Kistler says the new Type 4001A sensor meets all of these demands plus the integrated temperature element, accurate up to 275°C, monitors the temperature conditions inside the mould allowing automatic temperature compensation to correct the pressure signal due to thermal changes during the process.
Source: British Plastics & Rubber (www.britishplastics.co.uk)