Process drift and model-based control of forming operations

This work is focused on the thermoforming process, but can easily be leveraged to other discrete forming operations, such as blow moulding, composites and metal stamping. To date, little work has been done to address the control of state parameters describing the material behaviour during processing. The absence of control of state parameters has been one of the major problems plaguing the process as material property changes, environmental factors and machine operating drifts can significantly change the dynamics of the process. A hybrid process control methodology that relies on transfer functions derived from first principles is proposed in this work. This phase of the work focuses on the process model identification stage, looking at both empirically obtained deterministic transfer functions and a deterministic transfer function based on first principles. The work also analyses the drift of the process as well as the identification of the dynamic model.