Daniel Coupek

Proactive quality control system for defect reduction in the production of electric drives

State of the art in multi-stage production systems is End-Of-Line (EOL) quality control. The main drawback of EOL inspection is the off-line inspection at the final stage of the manufacturing chain, where already all possible defects of the production chain have been accumulated. Thus, a defective workpiece is machined wasting time, money and energy resources for creating a final product, which is out of tolerances and has to be recycled or scrapped. To overcome this drawback it is necessary to create solutions to reduce either defect generation or defect propagation. This paper focusses on the second approach, which aims at repairing defective workpieces by adapting consecutive process parameters in a multi-stage production system (downstream repair). By applying this concept to the production of electrical drives for power train applications, the effort needed for EOL testing can be reduced by shifting testing steps into the previous process chain. The currently used total flux measurement of laminated steel stacks is replaced by a space-resolved measurement. This permits the identification and local allocation of deviations in the magnetic field due to defective or weak magnets. The downstream repair strategy solves an optimization problem in order to compensate deviations in the magnetic field of single laminated steel stacks by adapting the assembly stage. Two repair strategies are discussed within this paper, namely sequential and selective assembly. In the proper assembling sequence, the laminated steel stacks are then assembled on the rotor according to the optimal assembling policy. Thus deviations of the laminated steel stacks are compensated.

Defect reduction in the production of electric drives by downstream compensation and space-resolved inspection

Improving the material efficiency in the production of electric drives is necessary as the electric automotive sector is growing very fast. Here, a method for early defect identification and downstream compensation, which allows defect reduction and consequently waste reduction, is presented. This reduces the waste motor parts (rotor stacks) and decreases the amount of rare earths to be recycled. A new inspection device was developed that allows a space-resolved in-line inspection of single rotor stacks as well as assembled rotors, in the same inspection station. This inspection device was realized as a demonstrator system, which is explained in detail in this paper. The inspection results are used as input for the downstream compensation methods, selective and sequential rotor assembly. Both methods combine stacks that are out of tolerances in such a way that the final rotor is within the specified limitations. Thus, low quality parts form a high quality assembly without having to scrap stacks and magnets.

Properties of electrically preloaded rack-and-pinion drives

Ball screw drives are very common in industrial applications and, therefore, thorough analyses of their characteristics exist. Rack-and-pinion drives are a good alternative, if large travel ranges and high dynamics are required. However, they are not scientifically and systematically analysed. Nowadays, either constant mechanical or electrical preload is often used in industrial applications to reduce the backlash of a drive train (Weck and Brecher in Werkzeugmaschinen 3: Mechatronische Systeme, Vorschubantriebe, Prozessdiagnose, 6th edn. Springer, Berlin, 2006). This paper describes the investigation of an electrically preloaded rack-and-pinion drive in an experimental rack. The focus is on backlash, stiffness, friction losses and bandwidth of the examined feed axis dependent on the preload. An open controller allows online variations of the drive system’s preload. The resulting effects are investigated experimentally. The paper shows that increasing preload reduces backlash and increases stiffness and bandwidth, but friction losses raise as well.

Cloud-based control for downstream defect reduction in the production of electric motors

Classical computing is shifted gradually into the cloud, offering completely new possibilities in information usage, computing power and application of learning algorithms. In this paper, a cloud-based architecture of control systems is investigated showing the benefit for multi-stage production systems. All sequential manufacturing and assembly processes are connected via a cloud-based architecture, which allows using information from a previous production step in one of the subsequent steps for downstream deviation compensation. This strategy is applied to the rotor production of electric motors in the automotive industry, as the current production shows high defect rates due to the lack of adequate sensor signals and optimization algorithms. The magnetization process of permanent magnets is executed in saturation, so that the generation of deviations cannot be avoided by process control or process optimization. Instead, the variance in the magnetization signal must be compensated in a downstream process, here the rotor assembly stage. Project results show how such a cloud-based architecture can increase the product quality while decreasing the amount of scrap parts in a real industrial scenario, consequently saving valuable resources like energy and raw materials. Reduction of deviations is crucial for this emerging industrial sector as electric motor production for vehicles is moving towards mass production.

Fabrication of Biomimetic and Biologically Inspired (Modular) Structures for Use in the Construction Industry

The transformation of biological paradigms into building construction involves the transfer of structure and system-defining properties from biological role models to construction-specific and innovative non-construction-specific systems and processes. The challenge of manufacturing biomimetic and bio-inspired structures includes the provision of methods and procedures that allow the mapping of biological features on a production-related description. The methodological approach requires the validation and verification of existing production methods at the small scale (model, elementary cell) in order to transfer findings to the production of components at the construction scale. Additionally, the biological features that cannot be reproduced by existing methods require further adjustment or the development of new methods for appropriate transfer. A basic condition for the further development of such production procedures is the possibility of manufacturing complex structures based on biological strategies concerning resource and energy consumption, waste production and greenhouse gas emissions.

Cloud-Based Control Strategy: Downstream Defect Reduction in the Production of Electric Motors

Classical computing is shifted gradually into the cloud offering completely new possibilities in information usage, computing power, and application of learning algorithms. In this paper, a cloud-based architecture of control systems is investigated showing the benefit for multistage production systems. All sequential manufacturing and assembly processes are connected via a cloud-based architecture, which allows using information from a previous production step in one of the subsequent steps for downstream deviation compensation. This strategy is applied to the rotor production of electric motors in the automotive industry, as the current production shows high defect rates due to the lack of adequate sensor signals and optimization algorithms. The magnetization process of permanent magnets is executed in saturation so that the generation of deviations cannot be avoided by process control or process optimization. Instead, the variance in the magnetization signal must be compensated in a downstream process, here the rotor assembly stage. Project results show how such a cloud-based architecture can increase the product quality while decreasing the amount of scrap parts in a real industrial scenario, consequently saving valuable resources such as energy and raw materials. Reduction of deviations is crucial for this emerging industrial sector as electric motor production for vehicles is moving towards mass production in the future.

Continuous Fused Deposition Modelling of Architectural Envelopes Based on the Shell Formation of Molluscs: A Research Review

Land snails produce a highly structured functionally integrated self-supporting surface from a composite of organic and inorganic materials that posses a potentially rich source of aspects for possible transfer into the technical realm. These investigations form a basis for the concept of a machine setup harvesting potentials for architectural manufacturing. A computational design tool, incorporating the limitations of the production mechanism, the design intent and structural, architectural and functional aspects, has been established to integrate the fabrication in early stages of the architectural design.