A comparison between experiments and predictions for the blow molding of an industrial part

Multi-Dimensional Regression Models for Predicting the Wall Thickness Distribution of Corrugated Pipes

Corrugated pipes offer both higher stiffness and higher flexibility while simultaneously requiring less material than rigid pipes. Production rates of corrugated pipes have therefore increased significantly in recent years. Due to rising commodity prices, pipe manufacturers have been driven to produce corrugated pipes of high quality with reduced material input. To the best of our knowledge, corrugated pipe geometry and wall thickness distribution significantly influence pipe properties. Essential factors in optimizing wall thickness distribution include adaptation of the mold block geometry and structure optimization. To achieve these goals, a conventional approach would typically require numerous iterations over various pipe geometries, several mold block geometries, and then fabrication of pipes to be tested experimentally—an approach which is very time-consuming and costly. To address this issue, we developed multi-dimensional mathematical models that predict the wall thickness distribution in corrugated pipes as functions of the mold geometry by using symbolic regression based on genetic programming (GP). First, the blow molding problem was transformed into a dimensionless representation. Then, a screening study was performed to identify the most significant influencing parameters, which were subsequently varied within wide ranges as a basis for a comprehensive, numerically driven parametric design study. The data set obtained was used as input for data-driven modeling to derive novel regression models for predicting wall thickness distribution. Finally, model accuracy was confirmed by means of an error analysis that evaluated various statistical metrics. With our models, wall thickness distribution can now be predicted and subsequently used for structural analysis, thus enabling digital mold block design and optimizing the wall thickness distribution.

On the Prediction of Pantographing that Occurs between Reinforcement Cords Embedded within Uncured Rubber Layers during Molding of Tires

Molding is a key stage in the manufacturing process of a rubber tire. An unvulcanized tire consists of several layers of rubber compounds, some of which are reinforced with sets of fabric cords or wire cords. The final shape of the tire, including the tread patterns and markings, is obtained after insertion of the tire into a curing mold and inflation with an appropriate pressure. The relative orientation of reinforcements may change during the inflation phase. This relative orientation change is referred to as pantographing, and it will affect the properties of the finished tire. Predicting possible changes of orientation of reinforcements during inflation is therefore useful for subsequent technological assessment.