Supervisor:
Lasse Schmidt

Co-Supervisor:

Assessment Committee:
Associate Professor Anders Hedegaard Hansen(Chair)
Associate Professor, Guido Tosello, Dept. of Civil & Mechanical Engineering, Technical University of Denmark
Director, Russell Speight, Simulation Engineering

Moderator:
Michael Møller Bech

Abstract:

 

The dissertation, titled “Robust Injection Moulding Concept for the Production of Uniform Plastic Parts Subject to Material Variance” explores novel techniques for machine, process, and part control in the production of plastic parts from materials with varying properties on an injection moulding machine.

Injection moulded parts are popular and are found everywhere in our daily lives; in cars, household appliances, toys, etc. These parts are favored due to their precise tolerances and relatively low manufacturing costs. A key challenge, however, is dealing with changes in raw materials while maintaining the tolerances of the produced parts. Injection moulding is a multidisciplinary field, as the parts are produced through the interplay of equipment, materials, and process parameters.

The dissertation addresses the key challenges of injection moulding control by focusing on machine, process, and part control. For machine control, a variable-speed electro-hydraulic drive is designed, and controllers are developed to control the hydraulic pressures in the system. For process control a 1D dynamic model is developed, describing the flows and pressures of molten plastic as it is forced into the mould cavity, where the geometry of the part is shaped. The model is used to design a nozzle pressure controller. Lastly, a part mass control scheme is presented. The effectiveness of the proposed machine, process, and part control methods is evaluated through moulding trials, with results showing improved consistency in part dimensions.

This research contributes to the broader knowledge base of injection moulding process control, providing insights that enable manufacturers to produce uniform plastic parts despite variations in material properties.