Untersuchungen zum Umformen von Feinblechen aus Magnesiumknetlegierungen

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A comparative analysis of ceramic and cemented carbide end mills

Milling of ferrous metals is usually performed by applying cemented carbide tools due to their high hardness, temperature and wear resistance. Recently, ceramic tool materials have been on the rise and enhanced the efficiency in machining. As ceramics are brittle-hard materials, tool manufacturing requires a sound knowledge in order to meet the tool requirements such as sharp cutting edges and wear resistance. In this study, milling tools made of the high performance ceramic SiAlON were compared to tools made from cemented carbide. For both tool materials, the influence of a prepared cutting edge was investigated. Both the tool manufacturing process and the cutting edge preparation processes are presented, followed by the application of those tools within milling experiments. In order to evaluate the efficiency of both tool types, the cutting forces and the cumulative process energy demand were analyzed. Additionally, surface roughness of the machined workpieces and tool wear were examined. It was found that the ceramic tools, although process forces were higher than for cemented carbide tools, exhibited by far lower energy consumption, less tool wear and finally generated lower surface roughness. © 2020, The Author(s)

Performance and Wear of Diamond Honing Stones

Honing is one of the most precise processes for the production of tribologically highly loaded cylindrical bores in different areas of technology. The honing stone specifications influence the process performance to a large extent. During machining, the honing stones are in permanent contact with the workpiece and subject to high mechanical loads. High strength steel and latest coating materials cause additional stress on the honing stones and induce increased wear. The objective is to determine process information for these material properties to support an effective process design. In experiments, the performance and the wear rates of several honing stone specifications were investigated. In this publication, the observed wear mechanisms are analysed and influencing factors for reduced wear are outlined

Multifunctional FRP-aluminum foam setup for battery housings of electric vehicles

The battery systems of electrified vehicles are characterised by increasing weight due to larger battery modules. A lightweight battery carrier structure can reduce the system weight by replacing heavy metallic housing components by materials like fibre-reinforced plastics (FRP) and aluminum. The battery housing has to meet several requirements, e.g. stiffness, crash and intrusion protection, proof of leakage and thermal management. Present battery housings are manufactured using pressure die-cast aluminum in combination with steel carrier structures and are cooled actively. A novel approach is a lightweight hybrid battery housing consisting of a thermoformed FRP as stiff outer shell and an integrated closed cell aluminum foam infiltrated with phase-change-material for passive thermal management. This multi-material setup enables substitution of functionally separated systems in one intelligent solution. In the Open Hybrid LabFactory an entire process chain was built up including the aluminum foaming process, the thermoforming of FRP with heating and consolidating as well as the integrated forming and joining process of FRP with aluminum foam. With the goal of application-orientated research, a battery housing of an existing electric car was used to define requirements such as design space and mechanical specifications. Based on parameter studies an optimised process setup was achieved, which will be described in this paper