Tailoring Thermal Energy Supply Towards the Advanced Control of Deformation Mechanisms in 3D Forming of Paper and Board

The temperature of the tools and the moisture content of the material play a significant role in the 3D forming of paperboard in terms of the degree of forming and the quality of the formed part. It is known that different forming mechanisms act within the paperboard in different areas of the deep drawing tools during the deep drawing of paperboard and that the success of the forming process is also based on a dynamic interaction between material moisture and tool surface temperature. However, it has not yet been investigated how the forming parameters can be influenced by an individually adjustable temperature for the individual tool areas and how they influence the complex interaction with the moisture content of the paperboard during the forming process. Due to the inhomogeneity of the natural fiber network of paperboard, rapid and directed temperature changes of the tools are also of interest in order to be able to react quickly to variations of material properties in order to prevent frequent process failure within a continuous production. In this paper, test tools with individually controllable heating zones were developed and the use of different heating technologies to improve the rate of temperature change was analyzed. These tools were used to investigate the influence of temperature in the individual sections of the deep drawing process and how the moisture content can be specifically controlled during the process. It was found that with modern heating technology, the deep-drawing tools can be tempered significantly faster and that a temperature difference between the blank holder zone and the drawing cavity zone has a positive influence on the formability and the fixation of the shape of the part produced. This effect was further enhanced by the fact that, thanks to the temperature tailored tool, it was possible to work with a very high moisture content of the paperboard.