Papers by Keyword: Hard Material

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Authors: Eiji Shamoto, Norikazu Suzuki
Abstract: Precision machining, named ‘elliptical vibration cutting’, and its application to ultraprecision / micro machining of some hard / brittle materials are introduced in the present paper. The elliptical vibration cutting has a superior cutting performance in terms of low cutting force, low cutting energy, low heat generation, long tool life for steels, sintered tungsten alloy, etc., and large critical depth of cut for ductile machining of brittle materials such as glasses and single crystal calcium fluoride, etc. Based on these basic advantages, practical ultraprecision / micro machining of the hard / brittle materials is successfully realized by employing the ultrasonic elliptical vibration tools, which have been developed for ultraprecision machining.
Authors: Meng You Huo, Jin Quan Xu, Jian Hua Zhang, Xing Ai, Yu Jing Hu
Abstract: This paper presents a PMAC-based combined CNC machine that integrates technologies of ultrasonic machining, electrical discharge machining and high speed grinding. As a multifunctional machine, it can provide diverse machining methods for different materials. For hard and brittle materials, it can conduct ultrasonic machining and high-speed grinding respectively or in a combined form; for conductive hard and brittle materials, electrical discharge machining with or without ultrasonic vibration could be implemented. Driven by AC servomotors, the mechanical structure of the vertical machine is mainly composed of a cross workbench for work piece handling, and a spindle head for tool feeding or high speed rotating. Besides those mentioned above, the system management program, the pulse power generator as well as the ultrasonic generator are also analyzed in this paper. Experimental results show that this machine has a wide range of application indeed and is suitable for various materials processing.
Authors: Kiyoshi Suzuki, Y. Tanaka, Manabu Iwai, Tetsutaro Uematsu, Katsushi Tanaka
Authors: Bing Suo Pan, Xiao Hong Fang, Yong Chang Tian
Abstract: For machining of hard and brittle materials, iron electrodeposit is a kind of matrix material with potential advantages for manufacture of diamond tools. Aiming at the problem of difficult codeposition of diamond in iron deposit, this paper adopts orthogonal design of experiment to study the effects of solution pH value, cathodic current density, alkylphenol polyoxyethylene (10) ether (OP-10) concentration and ammonium chloride concentration on codeposition of diamond, and then Fe-based diamond bits were fabricated and drilling tests in granite were carried out. The results show that pH value, cathodic current density, OP-10 concentration and ammonium chloride concentration all have statistically significant effect on codeposition of diamond in iron deposit, whose contributions to the variance of the weight of codeposited diamond are 37.45%, 32.05%, 13.13% and 12.38%, respectively. The result of drilling test indicates that Fe-based diamond bit can achieve much higher penetration rate than common Ni-based diamond bit.
Authors: Md. Mamunur Rashid, A.M.M. Sharif Ullah, Junichi Tamaki, Akihiko Kubo
Abstract: Hard materials based on Alumina (AN), Silicon Carbide (SC), Boron Carbide/Nitride (BC/N), Zirconia (ZN), and alike are often used to produce abrasive grains and coat cutting tools. These materials improve the performance of grinding/machining operations by providing an enhanced productivity, a longer grinder/tool life, and a better surface finish. On the other hand, they might leave some burdens on the environment. Therefore, eco-attributes (i.e., energy consumption, CO2 emission, NOX/SOX emission, water usage, recycle fraction, etc.) of these hard materials should be used to make an informed decision. This study deals with this issue and provides an evaluation of AN, SC, BC/N, and ZN based hard materials in terms of CO2 emission, NOX emission, SOX emission, and water usage. The outcomes of this study are useful for analyzing grinding and other abrasive processes for achieving eco-manufacturing.
Authors: Nivaldo Lemos Coppini, José C. C. Santana, Elesandro Antonio Baptista, Daniel B. da Rosa, Aroldo Alcantara
Abstract: In this work a factorial planning had been used to evaluate the CBN tool life during cut-ting SAE 8620 steel. Part U2222 of a TPGW 160408 insert of TX-LS TB650 and 2NU-SHMA6942 S7182BN300 classes from two manufacturers were used in this experiment. A 23 factorial design was used In cutting process to evaluate the behavior of the tool life and reason of the exchange of the part on influences of the chamfer (in S and T+S), the advancing speeds (0.09, 0.10 and 0.11 mm/rpm) at a cutting speed of 91.2 m/min. Model have been fit by variance analysis (ANOVA) and the processing optimization was done by response surface methodology (RSM). Results showed that a hyperbolic model had more adjusting than other models and the optimization showed a high life time for the TX-LS TB650 tool from A manufacturer on 0.09 mm/rpm of advancing speed, where it was observed that the pre-cranking was the reason of the exchange.
Authors: Li Hua Dong, Chun Hua Fan, Jian Huang, Hong Xia Luo
Abstract: The application of hard and brittle materials become wider and wider because its self-characteristics. It is used widely in finish machining of products, such as memory record device, information products, precision instrument, etc. Traditional grinding-polishing methods have not suited for precision machining requirements of hard and brittle materials. Carbide and ceramic are chosen as workpiece. Diamond polishing film is chosen as polishing tool. Polishing experiments are done by using self-made film polishing machine with high speed and cooling inside. Polishing mechanism and polishing technology of what polishing film polishes hard and brittle materials will be studied by changing polishing speed and diamond grain size and so on. The experimental study of wear shape of gringding grain, desquamation process of grain and surface quality of workpiece will be done in this paper so that the reasonable technology of polishing hard and brittle materials with high productivity is obtained. It enrich and perfect the ultra-precision machining theory. A new method of ultra-precision lapping and polishing of hard and brittle materials is provided.
Authors: Feng Jiao, Bo Zhao
Abstract: In order to deeply study the influence of ultrasonic assistance on material removal characteristics of hard and brittle materials, a series of ultrasonic assisted single-point scratch experiments have been carried out in this paper. Experimental results show that the assisted ultrasonic vibration is benefit to increase the critical cutting depth and enlarge the ductile regime of material removal. The main reason can be explained as the influences of blank cutting phenomenon, the decrease of the normal cutting force under the same depth of cut, the decrease of the material hardness under ultrasonic excitation and the shielding effect of lateral crack.
Authors: Wolfgang Tillmann, Evelina Vogli, Ingor Baumann, Benjamin Krebs
Abstract: Deep drawing of high strength steels imposes high tribological requirements on forming tools. Thermal spraying is regarded as a promising technology to improve the tool’s performance and the service life of the forming tool, as long as ambitious demands of the coating process are matched. In order to qualify a thermal spraying process for a surface technology in deep drawing it is crucial that the coating obtains an extremely dense structure and a smooth, near-net-shape surface. The study presented considers two different approaches to achieve those goals. The application of fine-scaled powders (<10$m) spraying through HVOF technique offers the opportunity to deposit dense coatings with very smooth surfaces. In contrast, it is also feasible to achieve very smooth and dense coatings by combining conventional powders with a subsequently densification procedure
Authors: Gui Wen Kang, Fei Hu Zhang, Shen Dong
Abstract: ELID grinding is widely used as a high-productivity and super-precision grinding method for hard and brittle materials. It continues grinding stably with metal bonded diamond wheel due to its in-process dressing. Magnetorheological finishing (MRF) is a novel precision finishing process for hard and brittle materials. In this paper, ELID grinding and MRF are adopted to get high surface quality and remove subsurface damage of hard and brittle materials. The results show that this combination gives attention to both efficiency and quality and can be used to replace conventional optics manufacturing.
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