Advances in Abrasive Technology IX

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Authors: Toshiyuki Obikawa, Ali Basti, Jun Shinozuka
Abstract: The finite difference method was applied to simulate temperature distribution in the workpiece, cutting zone and tool in the orthogonal cutting process with multilayer coated sintered alumina tools. The analysis was conducted under different cutting speeds, while experiments were carried out to measure temperatures in different positions of the tool rake face using tools with built-in thin film thermocouples developed by the authors. The temperature distribution calculated along the rake face was consistent with experimental data. This proved that the finite difference modeling developed can be applied to the prediction of cutting temperatures of aluminum alloys for a range of ultra high cutting speeds.
Authors: Q.L. Han, Yuan Li, Xi Peng Xu
Abstract: In this paper, an experimental study was conducted to compare the sawing of granite with thin and normal blades. The power drawn by the spindle and horizontal and vertical forces were measured. The width of sawing slot on the granite was examined after sawing. For both blades, power and forces increase with the depth of cut. The width of sawing slots for the thin blade was about 75% of the normal blade. The width of sawing slots for either thin or normal blade sawing became narrower in larger depth of cut.
Authors: Ze Sheng Lu, L. Yang
Abstract: Precision ultrasonic vibration cutting is a promising technology in field of precision and ultra-precision machining. It is a kind of the pulsing cutting process with a constant vibration frequency and sine-wave amplitude of vibration. In this article, a rational model of cutting force in vibration cutting is established, and the vibration cutting mechanism is analyzed. Specially, by the method of numerical simulation, the effect regulation of amplitude of vibration on cutting force is theoretically discussed for the first time in precision vibration cutting. And the relationship between cutting parameters and cutting force is probed into on the different cutting conditions.
Authors: M. Wang, Di Zhu, Ning Song Qu, C.Y. Zhang
Abstract: With the development of high performance of gas turbine engine, there is a tendency to design the ribs in the cooling hole in order to improve the heat transfer and cooling efficiency in a cooling passage. This paper focuses on a machining method of the burbulated cooling hole. The cooling hole is formed by electrochemical machining (ECM) process using a shaped electrode. The ribs on the hole wall form using ECM after the shaped electrode is lowed into the bottom of the straight hole machined in advance. The experimental results indicate that machining efficiency increases obviously. Various parameters affecting the forming of the cooling hole, such as voltages, electrolyte concentrations, and the material of the workpiece, are discussed in detail. Furthermore, the flow field and temperature field of the different type of cooling hole are analyzed using computational fluid dynamics (CFD) model and finite element method. Result shows that the heat transfer coefficient in rib channels could enhances significantly
Authors: X.L. Zhao, Yong Tang, Wen Jun Deng, F.Y. Zhang
Abstract: A coupled thermoelastic-plastic plane-strain finite element model is developed to study orthogonal cutting process with and without flank wear. The cutting process is simulated from the initial to the steady-state of cutting force and cutting temperature, by incrementally advancing the cutting tool forward. Automatic continuous remeshing is employed to achieve chip separation at the tool tip regime. The effect of the degree of the flank wear on the cutting forces and temperature fields is analyzed. With the flank wear increasing, the maximum cutting temperature values on the workpiece and cutting tool increase rapidly and the distribution of temperature changes greatly. The increase of tool flank wear produced slight increase in cutting forces but significant increase in thrust forces.
Authors: Seok Woo Lee, S.H. Nam, Hon Jong Choi, E.G. Kang, K.Y. Ryu
Abstract: Today, the trend in die and mold manufacturing is to pursue high-quality surface topology using high-speed finish milling operation. This paper presents a new approach to optimize machining conditions according to the required material removal rate (MRR), focusing on obtaining a high-quality surface. In this approach, the prediction model of surface roughness using the 2-staged artificial neural network (ANN) is employed for the objective function. Furthermore, an additional surface quality criterion is also used for the optimization problem using the genetic algorithm. It has been investigated that optimized machining conditions can be selected to obtain the high-quality surface within allowable reliability while maintaining a high-quality surface, under the given desired MRR.
Authors: Andrey A. Toropov, S.L. Ko
Abstract: The paper proposes a model of burr formation in feed direction during turning operation. Two cases have been considered in the model: continuous and discontinuous burr development. A computer program, made on the base of the model, allows simulation of burr development, and predicting burr form and dimensions. Experimental verification of the program showed that the model is suitable for the simulation of burr development in both continuous and discontinuous cases of burr formation. The experiment also proved that burr thickness can be predicted with considerable accuracy and that burr height can be determined with a maximum error of about 30%.
Authors: James C. Sung, Shao Chung Hu, Yen Shuo Chang
Abstract: The thick braze alloy coating can hold diamond much firmer than thin element coatings (Ti, Cr, Si) of commercial saw diamond grits. Moreover, the braze alloy can form metallurgical bonding readily with the metal matrix of saw segments. As a result, diamond saws that employ ABCD can cut much faster and last much longer than conventional designs. ABCD can be planted in metal matrix to form three dimensional pattern, the chemical bonding of diamond and its controlled spacing can virtually eliminate diamond loss due to pullouts and diamond breakage due to excessive impact force. The greatly increased number of working crystals can extend the segment life by one order of magnitude. With the thick coating, ABCD can join together to form needles or plates that could not be possible with thinly coated diamond. The ABCD needles or plates can be planted or arranged in a metal matrix to form a three-dimensional structure. Such unique designs can greatly expand the functions of diamond saws.
Authors: Kung Jeng Ma, Hsi Hsin Chien, Choung Lii Chao
Abstract: Alternated a-C/a-C:Cr coatings were made by DC magnetron sputtering from graphite and Cr target in an argon discharge. Mechanical and tribological properties were measured by indentation, scratch and pin-on-disc test. The critical scratch load of a-C/a-C:Cr multilayer coatings for total failure is approach 100 N. The friction coefficient remains within the range of 0.08-0.1 at loads between 10 and 40 N during a pin-on-disc wear test. The wear depth only reaches 0.6 μm after a one hour wear test. The greater compliance and fracture toughness of the a-C/a-C:Cr multilayer coatings allows greater strains or strain energy to be stored before coating failure, and hence significantly improves wear resistance
Authors: Qing Liang Zhao, Da Gang Xie, Ekkard Brinksmeier, Otmann Riemer, Kai Rickens
Abstract: A novel conditioning technique to precisely and effectively condition the nickel electroplated mono-layer coarse-grained diamond grinding wheel of 91m grain size was developed to fabricate a Diamond Micro Tool Array (DMTA) in ductile machining of brittle materials. During the fabricating process, a copper bonded diamond grinding wheels (91m grain size) dressed by ELID (electrolytic in-process dressing) was applied as a conditioner, a force transducer was used to monitor the conditioning force, and a coaxial optical distance measurement system was used to insitu monitor the modified wheel surface status. The experimental result indicates that the newly developed conditioning technique is applicable and feasible to generate required wheel topography of less than 2μm run-out error and grain geometries. The taper cutting test on BK7 proves the fabricated DMTA is capable of realizing ductile machining of brittle materials.

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