https://popups.uliege.be/esaform21/index.php?id=1236 Publications of Auteurs Thomas Bergs fr 0 https://popups.uliege.be/esaform21/index.php?id=4032 Electrically conductive and thereby electrical discharge machinable ceramics may gain further relevance for tooling applications and in chemical industry. They combine high chemical and thermal durability with high hardness and strength. While these properties represent a significant advantage for application, they are a major challenge for conventional machining. Due to the thermophysical removal principle, wire electrical discharge machining (WEDM) is a suitable manufacturing process for hardness-independent machining and may broaden the use of ceramics especially in case of customized complex parts. Up to now, there are only a few investigations on WEDM of electrically conductive ceramics, especially with regard to the surface integrity and the influence of the EDM process on the mechanical properties. A previous study investigated the influence of different WEDM technologies on the surface integrity and the resulting load-bearing capacity of a zirconia-tungsten carbide (TZP-WC) ceramic. Based on this investigation, the heat flow in this ceramic composite was calculated with the use of a heat simulation model and compared with the analyzed rim zone, in order to predict a priori reliable process parameters. Furthermore, the wire electrical machinability and the bending strength of alumina-zirconia-tungsten carbide (ATZ-WC) composite ceramics with different fractions of the respective phases were investigated to identify the correlations and verify the simulation model. Tue, 30 Mar 2021 10:32:47 +0200 Tue, 30 Mar 2021 10:32:47 +0200 https://popups.uliege.be/esaform21/index.php?id=4032 https://popups.uliege.be/esaform21/index.php?id=3793 Plunge milling is a critical process step in mass manufacturing of rectangular shapes in electrical connector components. These shapes are manufactured by drilling a pilot hole and subsequent plunge milling with a radial offset (pitch) one or more times. The plunged cavity serves as guidance for the final broaching cut. In light of new legislative initiatives, the electronics industry is forced to use lead-free Cu-Zn-Alloys for mass manufacturing of these connectors. The plunging tool is deflected due to the higher cutting forces experienced in machining of lead-free CuZn-alloys in comparison to alloys with lead. This results in an offset of the milled cavity and negatively impacts tool guidance in the subsequent broaching process. Therefore, the geometric tolerances cannot be met. In this paper, the effect of tool geometry and cutting parameters on the workpiece geometry in plunge milling is investigated. The effect of the microstructure of the work-piece materials CuZn37, CuZn42 and CuZn21Si3P on the tool deflection and cutting force components is examined. The tools used vary regarding the design of the corner in terms of the corner chamfer and the inner shaft thickness. Friction between chips in the tools inner flutes and the cavity walls reduced workpiece accuracy. Improvements were achieved by reducing the width of the cutting corner chamfers, using large inner flutes and applying low cutting parameters. Mon, 29 Mar 2021 14:39:29 +0200 Thu, 08 Apr 2021 20:31:31 +0200 https://popups.uliege.be/esaform21/index.php?id=3793 https://popups.uliege.be/esaform21/index.php?id=2575 Fine blanking is a highly productive process of industrial mass production with which high quality components in particular but not exclusively for the automotive industry are produced. The manufacturing process faces its limits at elevated tensile strengths of the materials to be processed. Consequently, high-strength steels can currently only be fine blanked to a limited extent. This can be overcome by lowering the flow stress of high-strength steels by means of inductive heating. A steel of high importance especially for industries with high hygiene standards such as medical and nutrition production is the stainless steel X5CrNi18-10 (1.4301). As a metastable austenitic steel which can initiate cutting impact on the press through martensitization, fine blanking of stainless steel is a challenge. X5CrNi18-10 is not a high-strength steel per se but becomes difficult to process due to the high hardness of the martensite phase, known as transformation-induced plasticity (TRIP) effect. Thus, in order to combine the possible advantages of the fine blanking process with inductive heating and the important properties of stainless steel, fine blanking of this steel was investigated with inductive heating prior to the fine blanking. The process forces and product quality properties such as die roll were investigated and found to be advantageous in comparison to non-heated fine blanking specimens of the same steel. The process forces and the die roll height decreased due to the heating. Wed, 24 Mar 2021 18:19:07 +0100 Fri, 02 Apr 2021 14:51:13 +0200 https://popups.uliege.be/esaform21/index.php?id=2575 https://popups.uliege.be/esaform21/index.php?id=1518 The quality of a forming process highly depends on the pressure applied to the workpiece. Consequently, the demand for higher workpiece qualities results in a demand for tools that can withstand high compressive stresses. Moreover, the tendency of using materials like high-strength steels as workpiece material, urges the need for tool materials that can withstand high compressive stresses and are resistant to wear. A class of materials that offer a combination of hardness or wear resistance and ductility are cemented carbides. However, these properties hamper their machining with conventional cutting technologies. Due to its electro-thermal working principle, Electrical Discharge Machining (EDM) is able to machine materials independently from their mechanical properties. On the other hand, the removal process is accompanied by thermal stresses, which can cause residual stresses and micro cracks near the machined surface. Due to their pre-existing stresses from the sintering process, cemented carbides are especially susceptible for these kind of damages. It is therefore necessary to identify the impact of EDM on the material. Different machining strategies are tested with two different types of cemented carbides and examined regarding their fracture toughness. The crack surfaces resulting from the three point bending test are microscopically inspected regarding failure initiation. Additionally pin-on-disc tests are conducted to determine the influence of the EDM strategies on the tribological properties of the machined cemented carbides. Mon, 22 Mar 2021 20:06:40 +0100 Mon, 05 Apr 2021 18:05:51 +0200 https://popups.uliege.be/esaform21/index.php?id=1518