In this paper, a special-purpose CAD/CAM software package, BliskCad/Cam, based on a commercial CAD/CAM software Unigraphics is developed to reduce difficulties in CNC-EDM of the shrouded turbine blisks. The software p...In this paper, a special-purpose CAD/CAM software package, BliskCad/Cam, based on a commercial CAD/CAM software Unigraphics is developed to reduce difficulties in CNC-EDM of the shrouded turbine blisks. The software package consists of five modules such as electrode design, path searching, and machining simulation module. Functions of BliskCad/Cam include parametrical reconstruction of 3-D model of the blisk, intelligent design of complex shaped electrode, automatic generation of NC codes, search of interference-free tool path for multi-axis NC-EDM and machining simulation, etc. Experimental verification is conducted by using BliskCad/Cam and the results show that it satisfies the requirements, and can realize precision machining and reduce accessorial time remarkably.展开更多
WC-Co is used widely in die and mold industries due to its unique combination of hardness, strength and wear-resistance. For machining difficult-to-cut materials, such as tungsten carbide, micro-electrical discharge m...WC-Co is used widely in die and mold industries due to its unique combination of hardness, strength and wear-resistance. For machining difficult-to-cut materials, such as tungsten carbide, micro-electrical discharge machining(EDM) is one of the most effective methods for making holes because the hardness is not a dominant parameter in EDM. This paper describes the characteristics of the discharge conditions for micro-hole EDM of tungsten carbide with a WC grain size of 0.5 μm and Co content of 12%. The EDM process was conducted by varying the condenser and resistance values. A R-C discharge EDM device using arc erosion for micro-hole machining was suggested. Furthermore, the characteristics of the developed micro-EDM were analyzed in terms of the electro-optical observation using an oscilloscope and field emission scanning electron microscope.展开更多
Micro electro discharge machining (micro EDM) is a feasible way tomanufacture micro structures and has potential application in advanced industrial fields. For therealization of micro EDM, it is necessary to pay caref...Micro electro discharge machining (micro EDM) is a feasible way tomanufacture micro structures and has potential application in advanced industrial fields. For therealization of micro EDM, it is necessary to pay careful attention to its equipment design and thedevelopment of process techniques. The present status of research and development of micro EDMequipment and process techniques is overviewed. A micro electro discharge machine incorporated withan inchworm type of micro feed mechanism is introduced, and a micro electro discharge machine fordrilling micro holes suitable to industrial use is also introduced. Some of the machiningexperiments carried out on the micro EDM prototypes are shown and the feasibility of the micro EDMtechnology to practical use is discussed.展开更多
Silicon Carbide (SiC) machining by traditional methods with regards to its high hardness is not possible. Electro Discharge Machining, among non-traditional machining methods, is used for machining of SiC. The present...Silicon Carbide (SiC) machining by traditional methods with regards to its high hardness is not possible. Electro Discharge Machining, among non-traditional machining methods, is used for machining of SiC. The present work is aimed to optimize the surface roughness and material removal rate of electro discharge machining of SiC parameters simultaneously. As the output parameters are conflicting in nature, so there is no single combination of machining parameters, which provides the best machining performance. Artificial neural network (ANN) with back propagation algorithm is used to model the process. A multi-objective optimization method, non-dominating sorting genetic algorithm-II is used to optimize the process. Affects of three important input parameters of process viz., discharge current, pulse on time (Ton), pulse off time (Toff) on electric discharge machining of SiC are considered. Experiments have been conducted over a wide range of considered input parameters for training and verification of the model. Testing results demonstrate that the model is suitable for predicting the response parameters. A pareto-optimal set has been predicted in this work.展开更多
A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication proc...A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication process of microelectrode,micro hole,silicon wafer and complex microstructure was discussed. The process rules of machining efficiency and the relative electrode wear rate as well as the machining mechanism and performance of silicon micro-EDM were also researched. Machining experiments showed that the microelectrode diameter as small as 6 μm and the micro hole with minimum size of 10 μm could be obtained steadily,and the maximum aspect ratios of microelectrode and micro hole were over 25 and 10 respectively. And silicon micro-EDM experiments showed that the micro beam with the aspect ratios over 15 could be obtained easily. And a micro beam with minimum size of 23 μm width on a silicon wafer with 420 μm thickness was achieved. At last,the microstructure machining technology for micro-EDM was also discussed. And a micro-facial sculpture with free space curved surface and size of 1 mm×0.3 mm×0.18 mm was also machined successfully.展开更多
Direct current and pulse plating of copper-zirconium diboride （ZrB2） composites were studied and the effects of current density （DC） and pulse duty cycle （PC） on the EDM performance of the composites were invest...Direct current and pulse plating of copper-zirconium diboride （ZrB2） composites were studied and the effects of current density （DC） and pulse duty cycle （PC） on the EDM performance of the composites were investigated. With increasing current density, the effect of grain refinement on the electro-discharge machining （EDM） performance of the composites compensates that of the decrease of ZrB2 content in the composites, which improves the spark-resistance of the material. Under the same average current density and other experiment conditions, a lower duty cycle yields better EDM performance probably because more ZrB2 particles are incorporated in the composites in this condition. However, at a still lower duty cycle （10%）, the particle agglomeration and the microcracks of the copper matrix occur, which considerably deteriorate the spark-resistance of the composites.展开更多
文摘In this paper, a special-purpose CAD/CAM software package, BliskCad/Cam, based on a commercial CAD/CAM software Unigraphics is developed to reduce difficulties in CNC-EDM of the shrouded turbine blisks. The software package consists of five modules such as electrode design, path searching, and machining simulation module. Functions of BliskCad/Cam include parametrical reconstruction of 3-D model of the blisk, intelligent design of complex shaped electrode, automatic generation of NC codes, search of interference-free tool path for multi-axis NC-EDM and machining simulation, etc. Experimental verification is conducted by using BliskCad/Cam and the results show that it satisfies the requirements, and can realize precision machining and reduce accessorial time remarkably.
基金supported by a Grant-in-aid for the National Core Research Center Program from MOST and KOSEF, Korea (No.R15-2006-022-01001-0)partly supported by Pusan National University Research Grand,2008
文摘WC-Co is used widely in die and mold industries due to its unique combination of hardness, strength and wear-resistance. For machining difficult-to-cut materials, such as tungsten carbide, micro-electrical discharge machining(EDM) is one of the most effective methods for making holes because the hardness is not a dominant parameter in EDM. This paper describes the characteristics of the discharge conditions for micro-hole EDM of tungsten carbide with a WC grain size of 0.5 μm and Co content of 12%. The EDM process was conducted by varying the condenser and resistance values. A R-C discharge EDM device using arc erosion for micro-hole machining was suggested. Furthermore, the characteristics of the developed micro-EDM were analyzed in terms of the electro-optical observation using an oscilloscope and field emission scanning electron microscope.
文摘Micro electro discharge machining (micro EDM) is a feasible way tomanufacture micro structures and has potential application in advanced industrial fields. For therealization of micro EDM, it is necessary to pay careful attention to its equipment design and thedevelopment of process techniques. The present status of research and development of micro EDMequipment and process techniques is overviewed. A micro electro discharge machine incorporated withan inchworm type of micro feed mechanism is introduced, and a micro electro discharge machine fordrilling micro holes suitable to industrial use is also introduced. Some of the machiningexperiments carried out on the micro EDM prototypes are shown and the feasibility of the micro EDMtechnology to practical use is discussed.
文摘Silicon Carbide (SiC) machining by traditional methods with regards to its high hardness is not possible. Electro Discharge Machining, among non-traditional machining methods, is used for machining of SiC. The present work is aimed to optimize the surface roughness and material removal rate of electro discharge machining of SiC parameters simultaneously. As the output parameters are conflicting in nature, so there is no single combination of machining parameters, which provides the best machining performance. Artificial neural network (ANN) with back propagation algorithm is used to model the process. A multi-objective optimization method, non-dominating sorting genetic algorithm-II is used to optimize the process. Affects of three important input parameters of process viz., discharge current, pulse on time (Ton), pulse off time (Toff) on electric discharge machining of SiC are considered. Experiments have been conducted over a wide range of considered input parameters for training and verification of the model. Testing results demonstrate that the model is suitable for predicting the response parameters. A pareto-optimal set has been predicted in this work.
文摘A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication process of microelectrode,micro hole,silicon wafer and complex microstructure was discussed. The process rules of machining efficiency and the relative electrode wear rate as well as the machining mechanism and performance of silicon micro-EDM were also researched. Machining experiments showed that the microelectrode diameter as small as 6 μm and the micro hole with minimum size of 10 μm could be obtained steadily,and the maximum aspect ratios of microelectrode and micro hole were over 25 and 10 respectively. And silicon micro-EDM experiments showed that the micro beam with the aspect ratios over 15 could be obtained easily. And a micro beam with minimum size of 23 μm width on a silicon wafer with 420 μm thickness was achieved. At last,the microstructure machining technology for micro-EDM was also discussed. And a micro-facial sculpture with free space curved surface and size of 1 mm×0.3 mm×0.18 mm was also machined successfully.
基金This work was financially supported by the National Natural Science Foundation of China (No. 59935110)the Science Founda-tion of Liaoning Province, China (No. 20062183).
文摘Direct current and pulse plating of copper-zirconium diboride （ZrB2） composites were studied and the effects of current density （DC） and pulse duty cycle （PC） on the EDM performance of the composites were investigated. With increasing current density, the effect of grain refinement on the electro-discharge machining （EDM） performance of the composites compensates that of the decrease of ZrB2 content in the composites, which improves the spark-resistance of the material. Under the same average current density and other experiment conditions, a lower duty cycle yields better EDM performance probably because more ZrB2 particles are incorporated in the composites in this condition. However, at a still lower duty cycle （10%）, the particle agglomeration and the microcracks of the copper matrix occur, which considerably deteriorate the spark-resistance of the composites.
