Optimizing Thermoforming Process Windows Using Strain Hardening Rheology Metrics
Strain hardening rheology metrics define thermoforming process windows by predicting extensional melt strength to eliminate corner thinning and sheet sag.
Non-Destructive Gauging
Meaning
Measurement of the thickness of polymer walls or layers without cutting or damaging the finished product ensures continuous quality control during production. This measurement methodology, known as non-destructive gauging, typically utilizes ultrasonic or terahertz sensor technologies to capture precise dimensional data. It allows moulders to verify that a part meets the specified tolerances before it is shipped.
The process is widely used in blow moulding and extrusion lines.
Physical Method
Ultrasonic waves are transmitted through the polymer to measure the time delay of the return echo from the back wall. This delay provides an accurate thickness measurement that forms the basis of non-destructive gauging. Advanced systems use terahertz radiation to measure individual layer thicknesses in co-extruded multi-layer films.
Economic Value
Eliminating the need to sacrifice parts for inspection reduces scrap rates and lowers total quality assurance costs. By using non-destructive gauging, an operator can adjust the extrusion die bolt settings in real time, preventing the generation of out-of-specification material. This immediate feedback loop reduces startup waste.
System Integration
Integrating the sensors directly into the production line allows for one hundred percent inspection of all manufactured parts. The data generated by non-destructive gauging can be fed back into the line controller to automatically adjust processing parameters. This automation ensures consistent part quality throughout the run.