Applied Mechanics and Materials Vol. 794

Abstract: Error compensation is a key to reach the geometric accuracies required for high precision machine tools. To prevent errors from affecting the machining process, compensation values for the feed axes can be used. However, conventional feed axes can only compensate deviations in their feed directions. By controlling its integrated hydraulic guiding system, the feed axis presented in this paper is capable of compensating errors in all other degrees of freedom as well. Using a specifically developed program, ideal parameters for the compensation of errors in a realistic 3D-axis-system were calculated. The axis’ characteristics were examined on a test rig for different types of controllers and compared to those parameters. It could be shown that the presented highly integrated hydraulic feed axis is capable of compensating typical errors resulting from such a 3D-setup.

Abstract: The intention of the research project „BaZMod“ [1], funded by the Federal Ministry of Education and Research (BMBF), is to develop connections for additional cyber-physical modules, such as intelligent tools, actuators and measuring systems, to machine tools. At present, everybody is talking about such intelligent systems, known under the catchword “Industry 4.0”. Using simulations, it is analysed in this paper how the media, data and energy transmission within the spindle unit can be expanded. An FE model of a spindle unit is created and validated with experimental data by solving an optimisation problem. Then transmission concepts and design solutions are suggested with respect to transmitting media, data and energy through the spindle shaft. In addition, it is presented how the necessary changes in design affect the static and dynamic system behaviour.

Abstract: This paper describes the design process of a high-speed cutting press with a linkage mechanism in its drive train. The whole process is carried out for a virtual prototype. The kinematic and dynamic properties of the six-bar linkage mechanism are optimised regarding boundary conditions coming from the production process and kinematic requirements. Using a rigid body model, the geometric dimensions and inertia parameters of the links of the mechanism can be determined. A finite-element (FE) model is build up to check the parts’ durability during work load. A verification of main results is realised on an experimental prototype made from rapid prototyping material.

Abstract: This paper covers the kinematics and dynamics modelling of the mechatronic model for a 6 DOF cable-driven parallel robot and derives a real-time capable simulation model for such robots. The governing equations of motion for the platform are derived using Newton-Euler formalism, furthermore, the pulley kinematics of the winches and a linear spring-damper based cable model is introduced. Once the equations of motion are derived, closed-form force distribution is implemented and simulation results of the real-time capable model for the cable-driven parallel robot IPAnema3 are presented. Given the real-time capability, the presented model can be used for hardware-in-the-loop simulation or controller design, but also for case studies of highly dynamic or large-scale robots.

Abstract: It is well-known that superimposed ultrasonic tool vibrations are capable of decreasing the forming force and the interfacial friction during the deformation of metal. The complex causes of this phenomenon were mainly investigated by focusing on oscillation frequencies above 20 kHz. Due to limitations of the load capacity and the power of the oscillating systems, mostly soft materials, such as aluminium and copper, were analysed. The present study is concerned with the development of a tool system for ultrasonic-assisted compression tests with a 15 kHz oscillation system. The advantages of this type of oscillating system are an increased power and robustness, which allow the testing of high strength materials. In preliminary ultrasonic-assisted compression tests with a S235JR steel a force reduction of up to 63 % was measured. The major challenges identified during the preliminary investigations are a transversal drift of the specimen, a periodic separation between the die and the specimen, a high sound emission and a high demand on the measuring and signal processing technology. Based on the technical challenges and the determined requirements a tool system is introduced.

Abstract: The servo press technology is used in industrial production for innovative and economic metal forming. The path-time-characteristic of the ram of servo presses can be adapted to individual requirements of various forming processes. To achieve a high dynamic, the rotary inertia of the drive train should be as low as possible. Thus, a flywheel is not suitable to provide the energy required for both, the forming process as well as the ram kinematic. Hence the eccentric shaft is driven by the electric motor only. As a consequence, the press force has to be provided completely via the torque of the servomotor. High investment costs resulting from the required size of the drive components is a challenge to be conquered. This pushes the costs for the drive components.Another challenge is the unbalanced power consumption of the servomotor. Energy-converting and energy-storing systems are essential to compensate the power peaks resulting from the forming process and inertia forces. Nevertheless, these systems are expensive and reduce the energy efficiency of the press. Facing these challenges, a novel and innovative drive concept for eccentric presses is being developed at the Institute of Forming Technology and Machines (IFUM). These drive concept base on mechanical and electrical power split and can possibly eliminate any disadvantages of conventionally servo presses. The function, the control concept and first steps of the realization of the power-split press drive are presented in this paper.

Abstract: The paper deals with the development and investigation of a novel, hybrid clamping technology for micro machining. This new technology was developed through a combination of the freezing and mechanical clamping. Then, its technical and economic characteristics, including achievable holding forces, clamping time, stiffness, accuracy, flexibility in terms of different workpiece and process parameters, etc. were determined by experiments. After that, they were compared with the corresponding characteristics of the conventional technologies. The results of this comparison allowed to draw a conclusion about the advantages and disadvantages of the developed hybrid clamping technology.

Abstract: The manufacturing of so called customer innovated products leads to changes in production planning and control. In order to master the complexity inherent to a production with batch size one, the use of autonomous systems is a possible solution. The implementation of such systems may involve problems concerning the acceptance of users, for example production planners, as they are complex to understand and to work with. The following article analyses this problem and points out the importance of a defined process and an appropriate interface between human and system to realise a successful interaction. In addition to that, an approach for the definition of requirements for this cooperation is introduced.

Abstract: In the last two decades a large amount of companies decided to establish productions sites all over the world in order to profit from cost benefits and to gain access to new markets and know-how. This internationalisation trend leads to more and more complex production networks. According to this development managers are confronted with growing intransparencies within their companies due to increasing information asymmetries, growing amount of interfaces and a growing effort for coordination. Nowadays a lot of strategic decisions, e.g. location decisions are made according to someone’s instinct. The usage of a valid data base within decision making processes can improve the quality of taken decisions. There are two ways to establish a sound data base: Manual data gathering, which is always associated with great effort or the usage of “big data”. Technologies from the era “Industrie 4.0” enable companies to gather and store a large amount of data. This data amount can establish transparency to support an objective assessment. Therefore the aim of this paper is the development of a method to aggregate production data systematically to support the strategic planning of global production networks.

Abstract: Technical progress in production technology, the advancement of ICTs as well as increasing social and economic imbalances and ever-scarce resources ask for new means of value creation. . With the spill over of the highly efficient and innovative open source principles to the world of physical goods and products new modes of value creation appear that put traditional economic strategies and assumptions into question by stressing collaboration instead of competition, knowledge sharing engineering and fostering the empowerment of the people to participate and get engaged.The here presented multidisciplinary OpenLabs concept takes into account these new patterns of value creation based on open source principles and is a suitable approach to increase the overall empowerment and participation in local communities in developing, but also in developed countries.