Key Engineering Materials Vols. 315-316

Abstract: It analyzed the conditions in hydrodynamic action of coolant in super high speed grinding area and described the conception of lubricate induce force in the paper. Using fluid dynamical lubrication theory, theory analyses and mathematics modeling on lubricate induce force in plane grinding with non-porous grinding wheel were carried out, also the computer simulations were done, and the conclusion was theoretically verified by tests in interrelated material documents. On the bases of this, by analyzing the effects of parameters and pointing out grinding wheel speed, grinding wheel width significantly influences the max dynamic pressure in grinding area, thus the analyses indicated that it rises with the speed of grinding wheel increasing.

Abstract: Cutting fluid is the essential material in metal cutting process. This paper mainly studies the influence of TEA-containing solution on cobalt leaching from cemented carbide tools and the leaching mechanism, and then identifies the effective inhibitor. The results are as follows: (1) TEA additive can make cobalt leach from cemented carbide tools. (2) Addictive of triethanolamine oleate in the solution can obviously inhibit the leaching of cobalt from cemented carbide tools and there exists the best proportion. (3) The mixture of triethanolamine oleate and borax has the best inhibition function. So it can conclude: The mixture of triethanolamine oleate and borax can obviously reduce the leaching of cobalt from the cemented carbide tools, which improves the working life of the cutter and reduces the danger of the fluid to human body.

Abstract: In this paper, a two-dimensional (2D) fast tool servo driven by piezoelectric actuators for real time error compensation in taper turning is described. A 2D tool post is made with a new structure with three leaf springs for each axis and its mounting platform positions at a corner, which makes it convenient for mounting the cutter. A control technique, “Forecasting Compensatory Control” (FCC), is implemented to perform an on-line prediction of the machining errors encountered. The on-line cutting experimental results have verified that an improvement of about 40% was achieved for roundness error of the workpiece in the taper turning operation by using the developed control algorithm.

Abstract: In order to make the operator freely walk in virtual environment (VE), a new prototype of VE system for assembly is presented in this paper. In this system, a special machine is designed and it enables the operator to walk inside the VE in any directions over a long distance without actually leaving the physical device. Images produced by the computer are projected upon the surface of a large spherical cap screen surrounding the operator by means of a group of high power projectors. Signals provided by the position sensors attached to the operator are used by the computer to update the projected images, which provides the operator the illusion of walking freely through the virtual scenes. This VE system can acquire wide field of view and form panorama surrounding the operator, which may enhance the realistic sense of simulation.

Abstract: Lithium tantalite (LiTaO3) possesses a combination of unique electro-optical, acoustic, piezoelectric, pyroelectric and non-linear optical properties, making it a suitable material for applications in high frequency, broad width-band SAW and BAW components, filters in television receivers, etc. The surface quality of LiTaO3 wafers decides the performances of the devices. In this paper, the technique of chemical mechanical polishing (CMP) was used to polish LiTaO3 wafers. The influences of the polishing parameters on the CMP processes of LiTaO3 wafers were analyzed in detail based on the measurement of the material removal rate, surface roughness and topograph of the polished wafers in different polishing conditions.

Abstract: In this paper we present a multifunctional combined CNC machine that integrates the technology of USM, EDM and grinding. For non-conductive hard and brittle materials, the machine tool could perform ultrasonic machining and grinding machining combined ultrasonic vibration; for conductive hard and brittle materials, electrical discharge with or without ultrasonic vibration could be implemented. Conductive engineering ceramics have been used for elementary experiments, the results show that it is more efficient and more stable for processing this kind of materials by using the multifunctional combined CNC machine. On the basis of brief introduction about the structure of the machine tool, this paper emphasizes the form of control system, the gap state inspection that can be used to ensure the stability in processing and the principle for servo control.

Abstract: This article investigates the cutting of Al2O3/TiC ceramics using a fixed abrasive diamond endless wire. The effect of wire speed and feed rate on material removal rate, cutting force, surface roughness and wire wear is investigated. The cut surface of Al2O3 /TiC ceramics is studied. This study demonstrates the advantage of fixed abrasive diamond endless wire cutting of Al2O3/TiC ceramics.

Abstract: The laser-melting process of SiC nano-particles coated on the plasma sprayed WC-Co coating was performed. The SiC nanocomposite coating was prepared, and the microstructure and the mechanical properties of it were investigated. After laser irradiated, parts of nano SiC particles are turned into the inner of coating with the nano-micro composite structure. The being of SiC nano-particles in coating brings the better fine microstructure and the higher densification. The wear-resistant property and the corrosion-resistant property of the coating with SiC nano-particles are improved more than the coatings prepared by laser melting process without the SiC nano-particles.

Abstract: A kind of new complex tools coating technology by EDM (Electrical Discharge Machining) is studied in this paper. Firstly the principle of this technology is discussed. In order to meet the coating requirement of the high-speed steel twist drill, milling cutter or other complex tools, a set of coating device is designed and fabricated secondly, and the tools with different dimension are coated successfully by this device. Finally the performance evaluation of coated twist drills is carried out through the drilling test.

Abstract: High strength, low thermal conductivity, high ductility and high work hardening tendency of stainless steels are the main factors that make their machinability difficult. In this study experiments for high-speed turning of 1Cr18Ni9Ti stainless steel were carried out with ceramic tools. The influence of cutting speed on tool wear, chip formation as well as chip color, and surface roughness were investigated. A decrease in tool nose wear was observed with increasing the cutting speed up to 210 m/min. Surface roughness (Ra) was also decreased with increasing the cutting speed. Correlation was made between the tool nose wear/surface roughness and the chips obtained at the three cutting speeds of 110, 160 and 210 m/min.