Control-Oriented Gray-Box Modeling for Thermoset Injection Molding

IFAC-PapersOnLine, vol. 59, pp. 13–18

Abstract

Cavity pressure control can enhance the repeatability of injection molding processes. While extensive research has focused on thermoplastic cavity pressure control, there is a notable gap in models and control strategies for thermoset injection molding. This study aims to develop a model structure for thermoset injection molding suitable for integration into a model-based control scheme. The modeling approach is intended to be as generalizable as possible and sufficiently flexible to adapt to various process conditions. At the same time, it should be easy to parameterize or to train. To address this challenge, we first derive a first-principles process model. In the second step, we integrate a feed-forward artificial neural network into this model, which learns parameters and source terms from past injection molding cycles, resulting in a gray-box model. The neural network outputs replace the initial model parameters with functions of system inputs, states, and time. We validate both models against experimental data from a thermoset injection molding machine using a fat-plate mold geometry and a phenolic resin compound. We identify limitations of the proposed approach and suggest potential solutions.

Authors 6

1. Christopher Schulte Aachen Institute of Automatic Control (IRT)

   RWTH Aachen University

   Affiliation as printed

   Institute of Automatic Control (IRT), RWTH Aachen University, Aachen, Germany

2. Moritz Mascher Aachen Institute of Plastics Processing

   RWTH Aachen University

   Affiliation as printed

   Institute of Plastics Processing (IKV) at RWTH Aachen University, Aachen, Germany

3. Christoph Zimmermann corresponding Aachen Institute of Plastics Processing

   RWTH Aachen University

   Affiliation as printed

   Institute of Plastics Processing (IKV) at RWTH Aachen University, Aachen, Germany

4. Heike Vallery Aachen Institute of Automatic Control (IRT)

   RWTH Aachen University

   Affiliation as printed

   Institute of Automatic Control (IRT), RWTH Aachen University, Aachen, Germany

5. Christian Hopmann Aachen Institute of Plastics Processing

   RWTH Aachen University

   Affiliation as printed

   Institute of Plastics Processing (IKV) at RWTH Aachen University, Aachen, Germany

6. Sebastian Stemmler Aachen Institute of Automatic Control (IRT)

   RWTH Aachen University

   Affiliation as printed

   Institute of Automatic Control (IRT), RWTH Aachen University, Aachen, Germany