Hybrid parts are strongly moving into the focus for lightweight applications. Unfortunately, the accurate, simulative design, which comprises the accurate prediction of final part geometry, is still a challenging task...
Hybrid parts are strongly moving into the focus for lightweight applications. Unfortunately, the accurate, simulative design, which comprises the accurate prediction of final part geometry, is still a challenging task. In the scope of this paper, an approach to improve the accuracy of appropriate finite element simulations is presented. To this end, the manufacturing history of the hybrid part is considered within the simulation of the part behavior. To create a finite element model of the considered hybrid composite, the intrinsic manufacturing process is modelled first. This includes the modelling of the thermoforming process of a fiber reinforced polymer as well as the sheet metal forming process for the fabrication of form fit elements. Then, the geometry of the hybrid part is deduced from the geometries of the single components. Afterwards, the material properties, including the local fiber volume content as well as the local fiber orientation, are mapped to the finite elements. Consequently, a workflow to create a finite element model which considers manufacturing history is developed and successfully tested.
Thermo-elastic effects are one of the major reasons for positioning errors in machinetools. Next to friction and waste heat from drives, the heat exchange with the machine's surroundings influences the temperatur...
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Thermo-elastic effects are one of the major reasons for positioning errors in machinetools. Next to friction and waste heat from drives, the heat exchange with the machine's surroundings influences the temperature field inside the machine tool significantly. The thermal parameters necessary to describe this heat transfer can be obtained through computational fluid dynamics (CFD) simulations. This paper presents a new method aimed at decoupling these CFD simulations from the thermo-elastic simulations in order to provide the heat transfer parameters quickly and efficiently for transient environmental conditions. This is done by defining a suitable set of load scenarios for the CFD simulations, clustering the resulting parameters with radial basis functions and interpolating them using characteristic diagrams.
The article describes a sequential process of micro cutting, laser structuring and laser finishing processes for machining dies and moulds metal forming, plastic moulding and other replication technologies exemplified...
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The article describes a sequential process of micro cutting, laser structuring and laser finishing processes for machining dies and moulds metal forming, plastic moulding and other replication technologies exemplified at microfluidic systems. Structure size, geometry, dimensions and the arrangement of the micro structures affect the process chain concerning order of laser and cutting processes with fundamental influence on producibility and overall machining time under consideration of reachable material removal rates. Further on the different machining processes allow to generate different surface profiles and different roughness properties. Especially laser ablation and laser polishing of surface details enable modifications of functional properties in the fluidic system, which can be multiplied by forming process.
Related to resource efficiency waste reduction is the crucial point in the processing of food. As shown in different Food Waste Studies the amount of waste in food processing is enormous. Up to 400.000 metric tons of ...
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Related to resource efficiency waste reduction is the crucial point in the processing of food. As shown in different Food Waste Studies the amount of waste in food processing is enormous. Up to 400.000 metric tons of edible food is disposed every year caused by wrong treatment, handling and processing. Processing is the major point to deal with. In the case of manual processing in a cantina kitchen waste can be classified into waste associated with overproduction, product damages or technical interruptions. To reduce the amount of loss by using technical solutions it is possible to reduce up to 60 % of loss during the processing. Related to the product itself the automation and especially the scheduling of the processes in a commercial kitchen is more complex than the scheduling of standard products e.g. in the automotive sector. This article shows a solution to extend the criteria of production planning within an automated food processing environment. The paper introduces a product model that prescribes the progress of product quality while processing.
Aluminium-copper hybrid parts, as a substitution to copper parts, result in weight and cost reduction, and are relevant in applications related to the electronic, heating and cooling sector. However, aluminium to copp...
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Aluminium-copper hybrid parts, as a substitution to copper parts, result in weight and cost reduction, and are relevant in applications related to the electronic, heating and cooling sector. However, aluminium to copper joined by thermal welding processes presents challenges in terms of achieving good joint quality. This is attributed to their dissimilar mechanical and thermal properties which result in large stress gradients during heating. This study investigated joining of aluminium to copper sheets by electromagnetic pulse welding, which is a solid-state process that uses electromagnetic forces for joining of dissimilar materials. Hybrid sheet welds were obtained for all parameters conditions, selected according to a Taguchi L18 design. The structural and mechanical characteristics were examined and related to the welding parameters by means of a Pareto analysis and response graphs. The welded zone started with a wavy interface with interfacial layers and defects and evolved to a flat interface without interfacial layers. The maximum transferable force depended on the minimum specimen thickness and the strength of the hybrid sheet weld. In case of aluminium sheet thickness reduction, the maximum transferable force was linearly correlated with the aluminium sheet thickness. High quality joints were obtained for no aluminium sheet thickness reduction and for a sheet weld strength which was at least as high as that of the base material. The most effective way to increase the transferable force was to lower the initial gap and to increase the free length, which resulted in no aluminium sheet thickness reduction. Alternatively, the use of a rounded spacer decreased the effect of the aluminium sheet thickness on the transferable force. An increase in weld width was achieved for an increase in capacitor charging energy and gap, whereas an increase in weld length was obtained for a decrease in gap. An increase in weld width did not necessarily result in an increase in t
Elastomer components are normally produced by a molding process. When it comes to small batch sizes this becomes inefficient due to the expensive production of the molding tool, and machining is an economic alternativ...
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Elastomer components are normally produced by a molding process. When it comes to small batch sizes this becomes inefficient due to the expensive production of the molding tool, and machining is an economic alternative. However, due to the very low Young's modulus elastomers are difficult to machine. The investigated approach to enhance machinability was to use cryogenic cooling during cutting elastomer components, changing their mechanical properties. Experiments in turning show that elastomers do not respond like ordinary metal materials. Hence this study is conducted to describe the effects occurring during turning elastomers assisted with cryogenic cooling. Therefore extensive tests were carried out to determine the material characteristics. Forces and tool temperatures were measured in turning tests. A rise in tangential cutting force by approximately 30% compared to dry machining verifies the change in material properties at very low temperatures. This correlates with the measured tensile strength at different temperatures. The examined surface integrity and the formed chips confirm the improvement in machinability under cryogenic conditions as a result of lower material deformation. In addition the friction between tool and chip was evaluated by applying a temperature dependent friction law.
In the course of increasing application of laser beam melting (LBM) technology for series production, LBM process monitoring becomes more and more important for quality control during and after the production process....
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This research work proposes a robotized workstation for automatic disassembly of electric vehicle motors. A novel image processing algorithm is proposed for autonomous detection of motor screws, to automate the task o...
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ISBN:
(纸本)9781467380270
This research work proposes a robotized workstation for automatic disassembly of electric vehicle motors. A novel image processing algorithm is proposed for autonomous detection of motor screws, to automate the task of motor disassembly. Instead of having a database of templates for matching, the screws are detected based on their characteristics with respect to its grayscale, depth and HSV values. Furthermore, with frame iterations, the accuracy of the system is increased mean while reducing its runtime. The algorithm is successfully tested and implemented and yields highly accurate results.
The processing of innovative lightweight materials to sheet metal components and assemblies with globally or locally defined properties is the object of this work. It takes a load-dependent design of components and as...
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The processing of innovative lightweight materials to sheet metal components and assemblies with globally or locally defined properties is the object of this work. It takes a load-dependent design of components and assemblies, for example, based on the composition of different construction materials or a targeted setting of component areas with specified characteristics to fully exploit the lightweight potential when substituting conventionally used materials. Different process chains for the manufacturing of roll-formed long products made of magnesium alloys and high-strength steels with locally defined properties will be presented in this paper. Depending on the kind of material to be formed and the desired product characteristics, different temperature managements are needed for capable processes. Due to limited formability at room temperature, magnesium alloys require a heating of the forming zones above 200–225 °C throughout the bending process in order to activate additional gliding planes and to avoid any failures in the radii. The realization of local hardening effects requires at least one process-integrated heat treatment when roll forming manganese–boron steels. For both processes, it is imperative to realize a heating and cooling down or quenching appropriate for the manufacturing of long products with the required quality. Additionally, proper line speeds that allow a continuously operated economical production have to be considered. Research results including design, FEA, realization and experimentation of the mentioned process chains and strategies will be described in detail.
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