Development of a Reliable Numerical Model for a Process of Band Extrusion for Ceramic Roofing Tiles to Improve Durability of Forming Tools

Abstract

The specifics of the ceramic industry processes result in high pressures acting on the set of forming tools, leading to intense wear, which directly affects production costs and increases environmental impact. Therefore, the analysis of improving the efficiency of the technological stage of clay band extrusion in the production process of ceramic roofing tiles, using a combination of laboratory, industrial, and numerical studies, is the subject of this work. Extensive laboratory and industrial studies on the operational durability of clay band forming tools demonstrated that the dominant mechanism of destruction is tribological wear, particularly intense abrasive wear. The work also emphasizes the need to enhance the interpretation of research results through the use of computer-aided design techniques for technology development. As part of the research, a comprehensive numerical model was developed, incorporating the definition of a constitutive model based on the Drucker-Prager equation, a rheological model of the studied material, and initial and boundary conditions reflecting the specifics of the extrusion process. A key aspect was developing the rheological model in a tabular form and based on the Hansel-Spittel equation. The friction conditions based on specially designed laboratory tests were also determined. The identification of the flow stress model parameters was carried out using inverse analysis techniques. The reliability of the proposed material model, as well as the model for the entire technological stage, was verified by comparing the calculation results with measurement results. The obtained numerical simulation results preliminarily indicate the correctness of the conducted research, as both the shape of the extruded band and the preliminary results of stress distributions in the formed mass and on the tools are acceptably consistent with experimental observations. Such a numerical model for simulating band extrusion in the production process of ceramic roofing tiles will enable a comprehensive and more in-depth analysis of tool wear, especially over a longer operational period. However, further verification of the modeling results is necessary, followed by additional research aimed at fine-tuning the numerical model to fully reflect the specifics of the studied process. It should be emphasized that the developed numerical model represents one of the first approaches to addressing this type of issue concerning the process of clay band extrusion through forming tools.