Applied Mechanics and Materials Vol. 794

Abstract: Fiber reinforced plastics are increasingly employed in the automobile industry. The process chain of resin transfer molding offers one approach for realizing structural components made of fiber reinforced plastic in high quantities. In order to increase economic efficiency, automated solutions for the subpreform assembly are required. There is also the need for mechanically highly stressable and at the same time economical joining techniques for joining fiber reinforced plastics with metal. The following article shall provide an approach to meet both of these requirements.

Abstract: The field of power electronics packaging presents intricate and interdisciplinary challenges. System costs, reliability and performance are strongly determined by various aspects such as mechanical design, materials, thermal management and interconnect technologies. The overall costs of the product depend mainly on the complete process chain in the module development. Automation as well plays an important role and facilitates higher production rates, efficient use of materials, better product quality, and reduced factory lead times. This paper focuses on emerging interconnection technologies of bonding semiconductor components to power electronic substrates like diffusion soldering, conductive adhesive bonding and reactive multi-layer bonding. An overview on the automation potentials and complexities in individual technologies for the manufacturing of reliable and cost-effective power modules is given and discussed. Thus, a basis is created for choosing optimal die-attach technology depending on economic and technologic demand by comparing the state-of-the-art and advanced technologies.

Abstract: Chatter vibrations and tool deflection are common challenges in metal cutting processes. In roughing operations, it is often the occurrence of chatter vibrations which limits the productivity. While finishing, when tolerances are small, the tool deflection can lead to violating tolerances and thus producing scrap parts. Beside the tool and tool holder, it is also the guidance system, especially in the z-axis, which influences the aforementioned phenomena. In this paper the influence of an electromagnetic guided z-axis is presented. It is focused on the influence of the high damping and the high static stiffness of the guide. Further benefits of this technology are outlined.

Abstract: Tool path generation for CNC machine tools is mainly responsible for quality, accuracy and productivity of the manufacturing process and therefore in the focus of research activities. Many approaches regarding this topic yield to complex algorithms and thus, demand for the availability of sufficient processing performance realizing this algorithms in a CNC real-time environment. For that reason this paper presents an approach on how to use multi-core processors for CNC tool path generation functions. A partitioning concept is presented allowing to concurrently execute multiple threads realizing interpolation and arc length calculation algorithms. At the example of B-spline interpolation the execution time of the tool path generation function could be reduced significantly using the presented approach.

Abstract: The rising amount and complexity of machine tool control software forces developers andvendors to increase software quality assurance measures, especially system regression tests. Thesetests are mostly conducted manually at real machines and thus error-prone, expensive and timeconsuming.This paper discusses the state of the art in machine tool control software testing andproposes a new approach for the automated test of machine tool control software. Its outstandingfeature is a manufacturer-independent test environment that makes it possible to test control softwareon different control types with minimum overhead. The approach bases on a hardware-in-the-loopsimulation system and implies a concept for a uniform access to the multitude of communicationinterfaces of today’s controls. Furthermore, the paper shows the problems that make such a tooldifficult to define and gives a concept for implementation.

Abstract: The aim of this paper is to present the design of a condition monitoring tool, its use for the intelligent configuration of pattern recognition algorithms, for fault detection, and for diagnosis applications. The modular design and functionality of the tool will be introduced. The tool, developed and implemented by Fraunhofer IPK, can be used, in particular, to support the development process of algorithms for condition monitoring of wear-susceptible components in production systems. An example of the industrial application of the tool will be presented. This will include the implementation of configured algorithms using the tool on an embedded system using Raspberry Pi 2 and MEMS sensor. Finally, the evaluation of these algorithms on an axis test rig at different operating parameters will be presented.

Abstract: Heat resulting from motors, moved contacts as well as cutting processes, causes time-dependent deformation of machine structures that reduces the precision of machine tools. For design optimization and especially for correction of thermal induced displacements, it is necessary to have compact models, which allow fast simulation of the thermo-elastic behaviour of the entire moving machine tool during the process. This paper presents an innovative simulation technology that permits, starting from CAD geometry through FE modelling, to come to a time-saving thermo-elastic calculation model of entire moved machine tools. Thereby, calculated temperature and deformation fields are of high geometrical resolution. Results and potentials of the new approach are demonstrated on example of a Hexapod machine tool.

Abstract: The numerous different possibilities to influence the thermal behaviour of machine tools preclude a generally agreed upon evaluation that considers their effectivity and energetic-economic efficiency. This is caused by their different modes of action and non-linearity in their interrelations. A variance-based sensitivity analysis makes possible a comparison of different factors regarding their impact on changes in relevant characteristics. Its functionality is explained and exemplified by a simple thermal problem.

Abstract: The measures taken to improve the thermal behaviour of machine tools are based on thermal models. The models are applied to support the design process and to correct the machine tool operation in a control-based way. Especially the models for correction purposes include uncertain parameters that cannot be estimated with sufficient accuracy. Thus these parameters have to be adjusted by means of measurements. During the adjustment process, a broad diversity of machine behaviour and model characteristics has to be taken in to account. Therefore, substantial time, effort and expert knowledge are required. To identify the key expenses, a generalized and systematic analysis of the adjustment process was carried out. First, the typical design of the models, the parameters of the sub models and the current adjustment procedure were investigated. Based on the results of the analysis, support requirements were identified. Afterwards first methods and software tools for efficient support were developed. This strategy is demonstrated using the example of a hexapod strut model.

Abstract: This paper gives a description of the challenges in the development of a generalized approach for the structure model based correction of thermoelastic errors of machine tools. The correction approach can be divided in modules. The challenges are described on the requirements of the modules.