A procedure for statistical analysis and uncertainty evaluation is presented with regards to measurements of step height and surface texture. Measurements have been performed with a focus-variation microscope over jet...
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ISBN:
(纸本)9780956679079
A procedure for statistical analysis and uncertainty evaluation is presented with regards to measurements of step height and surface texture. Measurements have been performed with a focus-variation microscope over jet electrochemical micro-machined surfaces. Traceability has been achieved using as reference contact measurements from a calibrated stylus instrument. A statistical analysis has been carried out and the method of least squares has been implemented to correct for systematic behaviours. The combined uncertainty has been evaluated accordingly and the expanded uncertainty has been finally calculated as the confidence interval of 95 %. Results show that agreement within single digit micrometre (dimensional measurements) and tenths of micrometre (surface parameters measurements) can be achieved with the proposed methodology.
Combining the working principle of electrochemical machining (ECM) with a universal rotating tool, like a wire, could manage lots of challenges of the classical ECM sinking process. Such a wire-ECM process could be ab...
Combining the working principle of electrochemical machining (ECM) with a universal rotating tool, like a wire, could manage lots of challenges of the classical ECM sinking process. Such a wire-ECM process could be able to machine flexible and efficient 2.5-dimensional geometries like fir tree slots in turbine discs. Nowadays, established manufacturing technologies for slotting turbine discs are broaching and wire electrical discharge machining (wire EDM). Nevertheless, high requirements on surface integrity of turbine parts need cost intensive process development and – in case of wire-EDM – trim cuts to reduce the heat affected rim zone. Due to the process specific advantages, ECM is an attractive alternative manufacturing technology and is getting more and more relevant for sinking applications within the last few years. But ECM is also opposed with high costs for process development and complex electrolyte flow devices. In the past, few studies dealt with the development of a wire ECM process to meet these challenges. However, previous concepts of wire ECM were only suitable for micro machining applications. Due to insufficient flushing concepts the application of the process for machining macro geometries failed. Therefore, this paper presents the modeling and simulation of a new flushing approach for process assessment. The suitability of a rotating structured wire electrode in combination with an axial flushing for electrodes with high aspect ratios is investigated and discussed.
Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and...
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Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition.
The requirements regarding workpiece surface quality, geometrical and positional accuracy as well as tolerances for linear and angular dimensions are increasing. Furthermore, the machinetechnology limits and defines ...
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ISBN:
(纸本)9780956679079
The requirements regarding workpiece surface quality, geometrical and positional accuracy as well as tolerances for linear and angular dimensions are increasing. Furthermore, the machinetechnology limits and defines the manufacturing quality directly. Hence, the fraunhoferinstitute FOR PRODUCTION SYSTEMS AND DESIGN technology IPK AND THE institute FOR machinetools AND FACTORY MANAGEMENT IWF of the TU Berlin have developed a new machine tool concept for ultra-precision machining. This enables two-side machining of the front surfaces of optical elements. The concept aims at increasing the economic efficiency of ultra-precision machining.
Micro milling is a well-established manufacturing process for mould and die industry, which gains an increasing scope of usage for medical and biotechnical components and applications. Apart from manufacturing of micr...
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ISBN:
(纸本)9780956679079
Micro milling is a well-established manufacturing process for mould and die industry, which gains an increasing scope of usage for medical and biotechnical components and applications. Apart from manufacturing of microsystems, micro milling is also being applied for production of function-oriented surfaces, which improves the component functionality. The influence on surface topography and surface roughness in the process of micro milling can be achieved by means of targeted high-frequency vibration of a workpiece. There was developed a system to perform vibration assisted micro milling, which excites a workpiece in two directions horizontally to the spindle axis. For exploring of vibration assisted micro milling there was developed a system which excites the high-frequency vibration of a workpiece in two directions horizontally to the spindle axis. Frequency, amplitude and phase shift of the oscillation are controlled in accordance to the rotational angle of the machine tool spindle. Therefore, a closed loop control of a workpiece actuation considering the actual spindle speed is implemented. The system enables 2 DOF vibration assisted milling up to f = 10 kHz with a maximum amplitude of a = 7,5 μm. With usage of necessary industrial hardware vibration assisted micro milling offers a new and fast way of process optimization and surface structuring. This paper presents detailed information on the device for vibration assisted micro milling and the results of the milling tests in order to show the high potential for further research activities in the area.
Hot stamping is an important technology for manufacturing high-strength components. This technology offers the possibility to achieve significant weight reductions. In this study, cushion-ram pulsation (CRP), a new te...
Hot stamping is an important technology for manufacturing high-strength components. This technology offers the possibility to achieve significant weight reductions. In this study, cushion-ram pulsation (CRP), a new technology for hot stamping on servo-screw presses, was investigated and applied for hot stamping. Compared to a conventional process, the tests yielded a significantly higher drawing depth. In this paper, the CRP technology and the first test results with hot stamping were described in comparison to the conventional process.
An approach to improve the wear behaviour of micro milling tools is a defined cutting edge preparation applying immersed tumbling. In experimental investigations a 3-axes machine tool is used to analyze the influence ...
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ISBN:
(纸本)9780956679079
An approach to improve the wear behaviour of micro milling tools is a defined cutting edge preparation applying immersed tumbling. In experimental investigations a 3-axes machine tool is used to analyze the influence of the wear behaviour of prepared micro milling tools with diameters D = 0.2 mm made of cemented carbide. During machining of steel X13NiMnCuAl4-2-1-1 the process behaviour is analyzed, the cutting forces Fc in the milling process are examined and the surface roughness of the workpiece is measured.
This paper shows a numerical and experimental analysis of the different problems occurring during or after the conventional self-pierce riveting with semi-tubular and solid rivets of the high strength aluminum alloy E...
This paper shows a numerical and experimental analysis of the different problems occurring during or after the conventional self-pierce riveting with semi-tubular and solid rivets of the high strength aluminum alloy EN AW-7021 T4. Furthermore this paper describes different pre-process methods by which the fracture in the high strength aluminum, caused by the self-pierce riveting processes, can be prevented and proper joining results are achieved. On this basis, the different approaches are compared regarding joint strength.
The development approach for an energy storage system focuses on optimal sized double-layer capacitor modules to reduce peak power and to avoid malfunctions of production machinery caused by voltage interruptions. The...
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ISBN:
(纸本)9781479982776
The development approach for an energy storage system focuses on optimal sized double-layer capacitor modules to reduce peak power and to avoid malfunctions of production machinery caused by voltage interruptions. The required kind of charging for the energy storage system and adjustment of voltage control parameters was executed for line-side converters of drive groups in production machinery. The energy efficiency of electric drives with and without such an energy storage system was investigated by means of active power measurements and simulations of electric power flows in Matlab/SimPowerSystems.
Ultra-precision cutting of stainless steel with diamond as cutting material needs modification of the workpiece material or special equipment for vibration assisted machining. In this paper detailed information about ...
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ISBN:
(纸本)9780956679079
Ultra-precision cutting of stainless steel with diamond as cutting material needs modification of the workpiece material or special equipment for vibration assisted machining. In this paper detailed information about the chemical reaction for direct cutting of stainless steel with binderless-cBN while turning is given. The effect of lubricant on the wear of binderless-cBN is shown and confocal Raman spectroscopy with confocal imaging was done on the cutting tools.
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