Grinding tool topography is one of the several key aspects of the modelling of a grinding process. Simplifying it could mean less processing time needed, but it can lead to inaccurate simulation results. Considering t...
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Grinding tool topography is one of the several key aspects of the modelling of a grinding process. Simplifying it could mean less processing time needed, but it can lead to inaccurate simulation results. Considering that, this research aims to develop a reliable method for NC-grinding processes with abrasive mounted points, describing the grinding tool surface using a single profile of kinematic cutting edges instead of its whole topography. In order to achieve this, numerical and empirical experiments were conducted proving the feasibility of the model to implement it for future simulations.
The high-precision cutting of cemented carbide with geometrical defined cutting edge is due to high tool wear restricted. A new promising diamond based cutting material for machining cemented carbide has been develope...
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ISBN:
(纸本)9780956679079
The high-precision cutting of cemented carbide with geometrical defined cutting edge is due to high tool wear restricted. A new promising diamond based cutting material for machining cemented carbide has been developed by SUMITOMO ELECTRIC Hardmetal Corporation, Itami, Japan. In this paper, detailed information about the properties of the developed binderless-PCD are given. Furthermore, results of experimental studies with binderless-PCD as cutting material while milling cemented carbide are shown. As the result of this work the successful application of binderless-PCD as cutting material for machining cemented carbide could be shown. An arithmetical mean deviation Ra = 28 nm could be achieved by using a spindle speed n = 50 000 1/min and a feed per tooth ft = 0.5 μm.
The production of special interior contoured tools made of cemented carbide is a time- and cost-intensive multistage sintering process. An alternative for economic, flexible and automated production is provided by a l...
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The production of special interior contoured tools made of cemented carbide is a time- and cost-intensive multistage sintering process. An alternative for economic, flexible and automated production is provided by a laser-based, additive manufacturing Selective Laser Melting process (SLM). In a shortened process chain near-net-shape and special interior contoured tools can be manufactured energy- and resource-efficiently in small batch sizes. An increase of the tool life is achieved by the use of wear resistant and tough cemented carbide material. This paper focusses on the process behavior of the agglomerated and pre-sintered tungsten carbide-cobalt (WC-Co) powder material in the SLM process. Depending on the exposure parameters, various types of micro structures can be generated and the original material profile can be significantly changed during the laser material interaction.
Producers of turbomachines for the aviation and energy sectors have to meet the future challenges regarding environment protection, resource conservation and profitability. As part of the 2014 market and trend analysi...
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Producers of turbomachines for the aviation and energy sectors have to meet the future challenges regarding environment protection, resource conservation and profitability. As part of the 2014 market and trend analysis on the subject of Life Cycle Engineering for turbomachinery, the market potential of the concept of Life Cycle Engineering for turbomachines as well as future trends and R&D issues have been identified. It has shown that the mechanical, chemical and thermodynamic characteristics of high-performance ceramics motivate new developments of Life Cycle Engineering in turbomachinery. However, particular material properties like high hardness and strength represent a challenge for the machining process of complex components made from high-performance ceramics. Since process and machining technologies are key components of the LCE concept, this paper will focus on the importance of a holistic hard machining of ceramic matrix composites with regard to technical and economic criteria.
Pedestrian controlled uniaxial vehicles for goods transport such as hand trucks offer intuitive manoeuvrability with little space requirements. The disadvantage of this class of statically underdetermined vehicles is ...
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Pedestrian controlled uniaxial vehicles for goods transport such as hand trucks offer intuitive manoeuvrability with little space requirements. The disadvantage of this class of statically underdetermined vehicles is the need for the user to apply force for both stabilisation and propulsion. Removing this disadvantage is the key to enable their use for convenient transportation of heavy goods over long distances. For this our solution approach is to equip the vehicle with controlled drives providing force for both balancing and propulsion. Different to uniaxial vehicles without payload or for passenger transportation controller's adaptation to kinematic and dynamic parameters is required here after every reload. The frame's pitch angle must be adapted with every change of load whereby the COG's position is not measurable with acceptable effort. Dynamic parameters vary in a wide range. We applied an adaptive controller based on backstepping combined with Kalman state estimation for stable balancing with adaptation to changed payload without need for external support from the user. The manoeuvre concept based on low interaction forces applied from the user to the vehicle frame is taking advantage of the underconstrained dynamics of the vehicle, and offers similar driving behaviour to the user with different load situations. Operating control levers for setting speed is not required. To allow for cheap production a design goal was not requiring sensor information of both load's absolute weight and user interaction forces. The adaptive control and state estimation concept was simulated based on the kinematic and dynamic model of our new uniaxial vehicle system designed for urban parcel distribution on foot. Simulation results show the correct operation of the approach.
The mold-making industry faces nowadays the challenge of selecting the appropriate manufacturing technology for machining micro molds, normally made of high strength and difficult-to-machine steels. This selection of ...
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ISBN:
(纸本)9780956679079
The mold-making industry faces nowadays the challenge of selecting the appropriate manufacturing technology for machining micro molds, normally made of high strength and difficult-to-machine steels. This selection of appropriate technology shall consider the productivity, the involved costs, the operating times, form accuracy and surface quality. The industry producing micro molds is facing the challenge of choosing from two technologies available: the micro milling and the die-sinking μ-EDM. With regard to identical cavities, experiments were conducted aiming the comparison of the technological limitations for both technologies, micro milling and die-sinking μ-EDM, in respect to form accuracy of parts, surface quality and machining time.
Experimental investigations carried out for this study aimed on developing a μ-EDM technology for producing smallest and finest structures with width of 230 μm and depth of 800 μm into a micro mold made of stainles...
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ISBN:
(纸本)9780956679079
Experimental investigations carried out for this study aimed on developing a μ-EDM technology for producing smallest and finest structures with width of 230 μm and depth of 800 μm into a micro mold made of stainless steel. The main goal was to develop and to optimize the μ-EDM technology concerning the machining time, the tool wear of the electrode, and the form and positioning accuracy of the features. The metrological analysis using measuring distinct devices enabled the choice of the appropriate μ-EDM technology for producing the final cavities. Total machining time below 16 min as well as a tool electrode relative wear below 65 μm could be achieved. The cavity with micro structures could be produced at the hardened steel with respect to the requirements, including the exact size of structures (226 μm width) and precise position of cavity on the workpiece. The die-sinking μ-EDM confirmed to be a suitable technology for producing the cavities with micro-structures in hardened steel.
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