共查询到20条相似文献,搜索用时 0 毫秒
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G. D’Urso G. Maccarini C. Ravasio 《The International Journal of Advanced Manufacturing Technology》2014,72(9-12):1287-1298
An experimental campaign based on the execution of through micro-holes on stainless steel plates was carried out using a micro-EDM machine Sarix SX-200. The experimental campaign was carried out by varying several process parameters, namely peak current, voltage and frequency. Tubular electrodes made of two different materials (tungsten carbide and brass) were used. A study of the in progress material removal rate (MRR) and tool wear ratio (TWR) during the drilling process was performed. Some mathematical laws governing the relation between process parameters and performance indexes were defined. Two technological windows representing TWR and MRR as a function of the hole depth, for different electrode materials, were obtained. 相似文献
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In recent years, the need for products containing micro-features has shown a pronounced and steady growth in several fields of application. For the development of micro-holed devices, one of the most important technologies is micro-EDM (Electro Discharge Machining). Micro-EDM can be considered as an ideal process to obtain burr-free micron-size features with high aspect ratios. In particular, micro-EDM is a non-contact material removal process in which rapid electric spark discharges remove the material composing the workpiece by means of melting and vaporizing phenomena. The present work deals with the fabrication of micro holes using micro-EDM technology. The investigation focuses on the influence of different electrodes and workpiece materials on the process performance, expressed in terms of tool wear ratio. In particular, the influence of four different workpiece materials (stainless steel, titanium, magnesium and brass), three electrode materials (copper, brass and tungsten carbide) and two different electrode shapes (cylindrical and tubular) was investigated. Moreover, an analysis of the geometrical characteristics of the micro holes in terms of conicity and diametrical overcut was carried out. An influence of electrode geometries, electrode material and workpiece material on the final output was found. 相似文献
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K. P. Maity Ravi Kumar Singh 《The International Journal of Advanced Manufacturing Technology》2012,61(9-12):1221-1229
Micro electro-discharge machining (micro-EDM) operation is a versatile operation to machine any hard conducting material to fabricate micro-products of different shape and size. The micro-holes are a common feature in many micro-products. It is a challenging task to improve the surface integrity and aspect ratio of holes. A number of controlling parameters affect the micro-EDM operation. In the present investigation, the optimization of micro-EDM operation has been carried out for fabrication of micro-holes using design of experiment technique using the Taguchi method. The circularity error, the recast layer and machining time has been analysed. The significant factors influencing the process have been found out. The workpiece is taken as copper and the tool is tungsten electrode. 相似文献
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Mustafa Ay Ulaş Çaydaş Ahmet Hasçalık 《The International Journal of Advanced Manufacturing Technology》2013,66(5-8):1015-1023
In this study, the gray relational analysis method was used to optimize the micro-electrical discharge machining (EDM) drilling process of Inconel 718 nickel-based superalloy with multiperformance characteristics. In order to determine the best factor level conditions, a full factorial experimentation was performed based on the micro-EDM parameters of discharge current and pulse duration. The hole taper ratio (H t) and hole dilation (H d) were the measured performances. By analyzing the used optimization results, it was observed that the pulse current was more efficient on performance characteristics than pulse duration. The characteristics of drilled surfaces and tool electrodes were also investigated by using optical and scanning electron microscopy. A linear regression model was developed to estimate the performances. The measured and model results were in a good agreement with correlation coefficients of R 2?=?0.897 and R 2?=?0.929 for H t and H d, respectively. It is concluded that the EDMed hole quality can be improved effectively through this approach. 相似文献
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Ichien Hsu C. C. Tsao 《The International Journal of Advanced Manufacturing Technology》2009,43(1-2):127-135
Drilling titanium alloys are difficult because of the inherent material properties, particularly the low thermal conductivity and high chemical reactivity. This paper presents the design of a frequency tracing system and the experimental investigation in ultrasonic-assisted drilling (UAD) of titanium alloy. In order to realize the degree of influence between developed frequency tracing system and cutting parameters (frequency tracing, operating voltage, drill diameter, feed rate, and spindle speed) in UAD of titanium alloy, a L18 (2?×?37) orthogonal array was employed. Based on the experimental results, the importance of drill diameter, feed rate, and spindle speed in assessing thrust force is highlighted. On the other hand, average thrust force reduction of 3.2% was realized with frequency tracing compared to without the frequency tracing counterpart in UAD of titanium alloy. Moreover, the best combination to get lower thrust force in UAD of titanium alloy is A2B2C3D1E3 (i.e., frequency tracing = YES, operating voltage?=?500 V, drill diameter?=?3 mm, feed rate?=?10 mm/min, and spindle speed?=?1,000 rpm) within the selected test range. 相似文献
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Boby John 《The International Journal of Advanced Manufacturing Technology》2012,61(5-8):585-594
The performance of a product is generally characterized by more than one response variable. Hence, the management often faces the problem of simultaneous optimization of many response variables. In recent years, a lot of literature has been published on various methodologies for tackling the multi-response optimization problems. Among them, the approach based on Taguchi’s quality loss function is very popular. This paper discusses a case study on multiple response optimization in carbonitriding process. The surface hardness, case depth, and dimensional variation of carbonitrided pellets were simultaneously optimized using quality loss function methodology. The optimum obtained through loss function approach was found to be superior to the ones obtained through optimizing the response variables separately. The result obtained through the implementation of the solution is also presented in the study. 相似文献
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Comparative study of different dielectrics for micro-EDM performance during microhole machining of Ti-6Al-4V alloy 总被引:3,自引:3,他引:0
G. Kibria B. R. Sarkar B. B. Pradhan B. Bhattacharyya 《The International Journal of Advanced Manufacturing Technology》2010,48(5-8):557-570
In microelectrodischarge machining (micro-EDM), dielectric plays an important role during machining operation. The machining characteristics are greatly influenced by the nature of dielectric used during micro-EDM machining. Present paper addresses the issues of micro-EDM utilizing different types of dielectrics such as kerosene, deionized water, boron carbide (B4C) powder suspended kerosene, and deionized water to explore the influence of these dielectrics on the performance criteria such as material removal rate (MRR), tool wear rate (TWR), overcut, diameteral variance at entry and exit hole and surface integrity during machining of titanium alloy (Ti-6Al-4V). The experimental results revealed that MRR and TWR are higher using deionized water than kerosene. Also, when suspended particles, i.e., boron carbide-mixed dielectrics are used, MRR is found to increase with deionized water, but TWR decreases with kerosene dielectric. Further analysis is carried out with the help of scanning electron microscope (SEM) micrographs, and it is found that the thickness of white layer is less on machined surface when deionized water is used as compared to kerosene. Also, a comparative study of machining time has been carried out for the four types of dielectrics at different machining parametric settings. Furthermore, the investigation on the machined surface integrity and wear on microtool tip have also been done in each type of the dielectrics with the help of SEM micrographs and optical photographs. Hence micro-EDM machining on Ti-6Al-4V work material with B4C-mixed dielectrics is performed in the investigation and reported the performance criteria of the process. It can be concluded from the research investigation that there is a great influence of mixing of boron carbide additive in deionized water dielectrics for enhancing machining performance characteristics in micro-EDM during microhole generation on Ti-6Al-4V alloy. 相似文献
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AbstractIn drilling in titanium alloys, heat trapped in a hole adversely affects tool life, hole surface quality and integrity. Therefore, modeling temperature distribution in drilling is vital for effective heat dissipation and improving quality of drilled surfaces. The existing numerical and finite element models consider only frictional heat, whereas the effect of shear heat generation and tertiary heat generation is neglected. In the present work, a comprehensive thermal model of the drilling process is developed by considering all heat generated in shear, friction and tertiary zones. The drill cutting edges are divided into a series of independent elementary cutting tools (ECT). The calculated heat flux loads are applied on an individual ECT in the finite element model to determine the temperature distribution and the maximum temperature around the cutting edge. The temperature in the drill was also measured experimentally with the help of an Infrared (IR) camera. The results of numerical simulations lie within the error of ~8.75% when compared to the prior studies, and ~5.41% when compared to our experimental work. The thermal model gives the temperature distribution, and the maximum temperature observed at the corner of cutting edge was 604.2°C at a cutting speed of 35?m/min. 相似文献
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K. Palanikumar 《Measurement》2011,44(10):2138-2148
Glass fibre-reinforced polymer (GFRP) composite materials are one of the important materials and are economic alternative to engineering materials because of their superior properties. This paper presents an effective approach for the optimisation of drilling parameters with multiple performance characteristics based on the Tagugch’s method with grey relational analysis. Taguchi’s L16, 4-level orthogonal array has been used for the experimentation. The drilling parameters such as spindle speed and feed rate are optimised with consideration of multiple performance characteristics, such as thrust force, workpiece surface roughness and delamination factor. Response table and response graph are used for the analysis. The analysis of grey relational grade indicates that feed rate is the more influential parameter than spindle speed. The results indicate that the performance of drilling process can be improved effectively through this approach. 相似文献
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Application of grey fuzzy logic for the optimization of drilling parameters for CFRP composites with multiple performance characteristics 总被引:1,自引:0,他引:1
Carbon Fibre Reinforced Plastic (CFRP) composite materials have potential applications in various domains. In machining, drilling is essentially required to join different structures. But CFRP drilling poses many problems that decrease the quality of holes. In this paper, Taguchi’s L27 orthogonal array is used to perform drilling of CFRP composite plates. To improve the quality of the holes drilled, the optimal combination of drilling parameters is chosen using grey relational analysis. Grey fuzzy optimization of drilling parameters is based on five different output performance characteristics, namely, thrust force, torque, entry delamination, exit delamination and eccentricity of the holes. Analysis of variance (ANOVA) is used to find the percentage contribution of the drilling parameters and found that feed rate is the most influential factor in drilling of CFRP composites. 相似文献
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Cryogenic wear behaviour of Ti-5Al-4V-0.6Mo-0.4Fe (Ti54) alloy sliding against tungsten carbide is investigated at different speeds, loads and distances. Empirical models based RSM are developed to predict wear characteristics of Ti54 alloy as a function of sliding conditions. It is found that experimental and predicted results are in good agreement. Besides, cryogenic wear is substantially lower than dry wear. SEM and EDS analyses of worn surfaces and wear debris reveal that cryogenic sliding is significantly influenced by changing material properties along with boundary lubrication performance. The study has shown that modes in dry sliding are adhesion and delamination whereas in cryogenic sliding they are abrasion and delamination. 相似文献
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Xiangzhi Wang Zhidong Liu Rongyuan Xue Zongjun Tian Yinhui Huang 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):979-987
This study investigated the influences of dielectric characteristics, namely, electrical conductivity, oxidability, and viscosity on the electrical discharge machining (EDM) of titanium alloy. A new kind of compound dielectric with optimal processing effect was developed based on the identified effects. Comparative experiments on titanium alloy EDM in compound dielectric, distilled water, and kerosene were performed to analyze the difference in material removal rate (MRR), relative electrode wear ratio (REWR), and surface roughness (SR). The experimental results revealed that titanium alloy EDM in compound dielectric achieved the highest MRR, a lower REWR than that in kerosene, and better SR and fewer micro-cracks than that in distilled water. 相似文献
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The paper presents a study of the possibility of using composite nanostructured ceramic materials and crystals based on zirconia as bearing materials for dry operation at temperatures of up to 150°C. The results of experimental study of the dry friction of the materials in pair with alpha-titanium alloy VT-9 are presented. It is shown that at a sliding velocity of 0.004 m/s, contact pressure of 3.3 MPa, and temperature of 150°C, their antifriction properties do not differ significantly. ZrO2 crystals have a slight superiority in wear resistance because of their higher microhardness. The wear resistances of the alpha-alloy in pair with the ceramics and the crystal are practically the same. A power pattern of the dependence of the wear rate on the pressure for the ZrO2 crystal and the VT-9 (α) alloy is confirmed. 相似文献
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C.-M. Hsu C.-T. Su D. Liao 《The International Journal of Advanced Manufacturing Technology》2004,23(11-12):896-902
This study presents an integrated procedure using neural networks and exponential desirability functions to resolve multi-response parameter design problems. The proposed procedure is illustrated through optimising the parameter settings in the fused bi-conic taper process to improve the performance and reliability of the 1% (1/99) single-window broadband tap coupler. The proposed solution procedure was implemented on a Taiwanese manufacturer of fibre optic passive components and the implementation results demonstrated its practicability and effectiveness. A pilot run of the fused process revealed that the average defect rate was reduced to just 2.5%, from a previous level of more than 35%. Annual savings from implementing the proposed procedure are expected to exceed 0.5–1.0 million US dollars. This investigation has been extensively and successfully applied to develop optimal fuse parameters for other coupling ratio tap couplers. 相似文献