https://popups.uliege.be/esaform21/index.php?id=333 Index terms fr 0 https://popups.uliege.be/esaform21/index.php?id=1931 Cold forging tools become increasingly complex and require enhanced functionality, especially in the context of digitisation. Conventional subtractive manufacturing processes often reach their limits when the geometric complexity of the workpiece increases, hence additive manufacturing processes have become increasingly important in the last decades. Additive manufacturing processes have already been used in many fields of manufacturing technology to produce tool components with promising results, but the potentials of additive manufacturing processes have not yet been applied to cold forging tools. Therefore, the Institute for Metal Forming Technology (IFU) of the University of Stuttgart has developed an additive manufactured cold extrusion tool with integrated functional features. As functional features in the additive manufactured extrusion tool, a close contour glass fiber sensor for temperature measurement, a cooling system and a lubrication system for the controlled injection of minimal lubricant amounts during the forming process were integrated. Due to the integrated functional features, structural degradation appears in the tool, therefore the structural-mechanical tool properties were analyzed numerically with the FE-Software DEFORM 3D™ in this report as well. Furthermore, the additive manufactured cold extrusion tool was experimentally evaluated in sequentially executed extrusion operations. Thereby the integrated functional features were used and gathered data were recorded. As a result of the experimental forming tests, near-contour temperature measurements in the extrusion tool with and without the use of the integrated cooling system as well as the modification of the maximum punch forces by an inline lubricant application were obtained. In addition, the experimentally determined temperature fields in the extrusion die are validated with numerically calculated results. Tue, 23 Mar 2021 10:41:38 +0100 Mon, 12 Apr 2021 10:08:38 +0200 https://popups.uliege.be/esaform21/index.php?id=1931 https://popups.uliege.be/esaform21/index.php?id=331 Harmonic decomposition is an analytical technique that is able to express a manifold surface as the sum of a number of simple surface harmonic components. By reconstructing the initial geometry using a reduced number of components, a similar surface is obtained with a lower level of geometric detail. Because small features are filtered out and the resulting surface lies equal parts above and below the original surface, a tailored multi-step SPIF (Single Point Incremental Forming) processing strategy can be devised. This sequential SPIF strategy uses three processing passes to form a workpiece. The first step is a regular SPIF operation using a conventional toolpath strategy to form the reduced geometry. Two finishing steps are then needed, one from the same side to form the smaller features that lies deeper than the reduced geometry and one backwards pass from the other side of the sheet. To add features that need to be shallower than the reduced geometry, the part is flipped around. The used sequence of these finishing steps and the toolpath strategy used significantly influence the final part accuracy and surface quality. The advantages and disadvantages of four of these combined strategies are examined and compared to regular SPIF. Fri, 19 Mar 2021 15:38:57 +0100 Mon, 05 Apr 2021 18:02:12 +0200 https://popups.uliege.be/esaform21/index.php?id=331 https://popups.uliege.be/esaform21/index.php?id=2742 Rotary draw bending (RDB) is a forming process that is commonly used to bend tubes with small wall thicknesses and small bending radii. One of the limitations of this process is the formation of wrinkles caused by compressive stress on the inner bend. In order to design the bending process without wrinkles and to determine the necessary process parameters, adjustment tests are required. Within this work, a fuzzy controller is to be developed which automatically prevents the formation of wrinkles and thus eliminates the need for time-consuming set-up tests to determine the necessary process parameters. The fuzzy controller is based on fuzzy set theory and fuzzy logic. In connection with a rule base it is possible to simulate the human decision process. A fuzzy controller is programmed based on a max-min controller, with the required rules resulting from previous bending tests. After the fuzzy controller has been implemented, it must be connected to the bending machine by suitable interfaces. The input values, which indicate wrinkles, are measured by sensors during the bending process and provide the controller with data. The fuzzy controller then uses the control base to specify the required control variables. After programming has been completed, practical validation tests were carried out. In the validation tests using different tube wall thicknesses and materials, a significant reduction of wrinkles is achieved. Bending of completely wrinkle-free tubes is also possible due to the automated finding of optimal tool settings. Using the fuzzy controller eliminates the need for costly adjustment bends, resulting in significant time and cost savings. Wed, 24 Mar 2021 18:54:12 +0100 Fri, 02 Apr 2021 16:05:33 +0200 https://popups.uliege.be/esaform21/index.php?id=2742