The present article deals with the simulative representation and optimization of acoustical properties of a train gearbox with one helical gear stage. At first, a dynamic model of the initial gearbox based on manufact...
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The variance-based sensitivity analysis can be used as a statistical procedure to evaluate different individual measures to influence the thermal behaviour of machinetools. It provides specific ratios for parameters ...
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The variance-based sensitivity analysis can be used as a statistical procedure to evaluate different individual measures to influence the thermal behaviour of machinetools. It provides specific ratios for parameters affecting the variance of the output parameters that are not comparable in any other way. This method is implemented by means of large samples used in a simulation model which reduces computing time and is oriented towards physical objects. Furthermore, conditional and total variances are estimated. The article describes the principles of modelling with discrete elements to integrate all variants into one simulation model, the definition of input and output parameters and sample generation considering the parameter-specific distribution functions and parameter dependences. To evaluate the applied measures, temperatures, temperature differences, heat flow and time required until achieving thermal equilibrium are examined as such, or in relation to the deployed energy. The implementation is demonstrated by means of two examples. One refers to the design, and the other one deals with the operation phase of existing machinetools.
forming processes are generally characterized by a high degree of material utilization as well as short process times and, consequently, a decent economic efficiency. Considering their application in the manufacturing...
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forming processes are generally characterized by a high degree of material utilization as well as short process times and, consequently, a decent economic efficiency. Considering their application in the manufacturing of large spur gears, forming processes offer a significantly attractive characteristic for the production of essential gearing components commonly used in wind turbines or marine engines. Furthermore, the hot forming process can be defined as an incremental forming process which enables the use of relatively low forming forces and results in a more compact design of the used machines. These conveniences are utilized in terms of roll forming with round tools to form gears and threads in a competitive way. Based on experiences gained over many years of researching rolling technologies, a cross-rolling process characterized by round tools with outer gearings was elaborated to realize a hot forming process for gear rolling of large spur gears at the fraunhoferiwu Chemnitz. Based on the already researched forming of smaller dimensioned gears, rolling trials utilizing a new hot-formingmachinery - including defined inductive heating process before rolling - to realize large gears with outer diameters of up to 1000 millimeters were conducted. In terms of realizing this ambition, the derivation of the designated machine parameters for rolling large gears in real-life dimensions can be defined as a crucial factor. Consequently, the experimental research was followed by a mathematical analyzation of the forming forces, momenta as well as the necessary steps to determine the best possible scaling factors for the work pieces.
The paper presents a consistent numerical simulation method for calculation of heat sources and heat fluxes in milling processes. First of all, by means of finite element simulation of the interrupted chip formation p...
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The paper presents a consistent numerical simulation method for calculation of heat sources and heat fluxes in milling processes. First of all, by means of finite element simulation of the interrupted chip formation process the cutting heat source is calculated. Next, the non-steady-state heat fluxes into the workpiece, the chips and the tool are computed numerically. The computed fluxes serve as boundary conditions for thermo-mechanical FE workpiece and tool models. The numerical models are fitted and verified by experiments of S235 steel. The simulations show a good match with the force and temperature measurements of the cutting processes.
The paper describes the comparison of numerical solution, analytical approach and experimental results calculating heat sources and heat fluxes in a milling process with the aim of the calculation of the temperature d...
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The paper describes the comparison of numerical solution, analytical approach and experimental results calculating heat sources and heat fluxes in a milling process with the aim of the calculation of the temperature distribution. Analytical solutions for standard geometries are superposed in order to represent the tool best possible. Exposed with the heat sources calculated by finite element simulation of the interrupted chip formation process the solution of these analytical representation is compared with numerical ones. These have been investigated in previous research on a consistent numerical simulation method for calculation of heat sources and fluxes in milling. Both models are fitted and verified by cutting experiments.
At present a plurality of manufacturing methods, different manufacturing processes and manufacturing equipment are known in order to produce and customize work pieces and products. A new systematic approaches for the ...
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At present a plurality of manufacturing methods, different manufacturing processes and manufacturing equipment are known in order to produce and customize work pieces and products. A new systematic approaches for the analysis and evaluation of manufacturing methods bases on the energy-information model as a conceptual approach to the comparative integrated manufacturing efficiency in production engineering. The integrated manufacturing efficiency is equal to the product of the efficiencies of matter, energy and information. The Comparative Integral Manufacturing Efficiency is the product of Quality rate, Effectiveness, Availability, devided by the product of (used Energy, used material, Emission ratio). A case study compares additive and removal process efficiencies for the production of a hollow cylinder. Proposed method for comparative integrated manufacturing efficiency will offer resource-efficient strategies for the creation and optimization of processes and technology applications.
The flowing lubricant in the oil wedge between the slide and guide rail creates hydrodynamic pressure that leads to a displacement of the carriage, which depends on the sliding surface geometry and the slides velocity...
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The flowing lubricant in the oil wedge between the slide and guide rail creates hydrodynamic pressure that leads to a displacement of the carriage, which depends on the sliding surface geometry and the slides velocity. This paper describes an approach to calculate the resulting complex displacement. Therefore, two methods were combined. The simulation of the floating by using the finite difference method was integrated in the numerical calculation of the balance of the whole carriage. Considering a real sliding surface geometry of a test bench, the experiment verification of the approach for velocities up to 40m/min showed a good conformity.
The pulsed electrochemical machining (PECM) with oscillating cathode is a manufacturing technology which is used for shaping and surface structuring of different workpieces, e.g. impact extrusion punches. The principl...
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The pulsed electrochemical machining (PECM) with oscillating cathode is a manufacturing technology which is used for shaping and surface structuring of different workpieces, e.g. impact extrusion punches. The principle behind the ECM-process is the controlled anodic dissolution of the workpiece material without any thermal or mechanical impact and independent from workpiece material hardness. In this study, a new multi-scale approach for the modelling of PECM with oscillating cathode was created integrating the short and long time scale physical phenomena. In the short time scale simulation step (t < 0.02 s) the physical processes (current density distribution, motion of cathode, heat and hydrogen generation) during one single oscillation were analyzed. An averaged dissolution speed at the anode boundary over the small time range was calculated. The averaged values were imported as initial and boundary conditions into the long times scale simulation step (t > 10 s). Within this simulation step, the anodic dissolution was simulated by deforming the geometry. This approach allows simulations for long overall time ranges (t > 1000 s) while considering the short times scale processes in combination with a relatively small computational effort. This multiscale and multiphysics model helps to analyze the differences between front and lateral working gap and supports the process design for the pulsed electrochemical machining with oscillating cathode.
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