Materials Science Forum Vols. 800-801

Abstract: A new type of hydrostatic liquid bearing utilizing traveling waves is proposed and analyzed in this research. In principle, the moving part of the proposed bearing is supported by a liquid film generated by the traveling wave transportation, which creates a liquid flow between the bearing and guide surfaces. A numerical simulation model for the unsteady and incompressible flow due to the traveling wave motion of the bearing surface is developed based on Navier-Stokes equations. The equations are solved discretely by dynamically meshing the isotropic 2D model and updating the boundary conditions. It reveals that the floating force varies with a nonzero average value. In order to suppress the undesirable fluctuation, voltage-offsetting technique has been proposed. Simulation results show that the steady floating force can be obtained. The proposed bearing design is ought to eliminate drawbacks of conventional hydrostatic bearings such as supply of external pressure source, use of compressor, and tubes while still achieving comparable static and dynamic capabilities.

Abstract: The wear morphology of rake face and flank face of tool is investigated by turning titanium alloy TC4 with CBN solid tool. It has been observed that the main wear form of rake face and flank face of tool is groove wear. The relation between tool flank wear and cutting speeds, feed rate, and cutting depth obtained from experimental data is given.

Abstract: With mechanical processing requirements' development direction translates to highprecision, high efficiency, high quality, intelligence and specialty etc. Wedge-caulking's processinghas a lot of problems in our country energy industry market , the problems mainly show lowefficiency, poor accuracy, product quality and technical indicators are difficult to guarantee. Thispaper developed a high precision, high efficiency, intelligence, high quality and specialty machinetool, the enterprise practice results show that the NC wedge-caulking special machine tool provide thetechnical support and equipment protection for our country motor manufacturing. It has the very goodpractical value.

Abstract: For DVT500 vertical lathe of the carrying capacity of heavy hydrostatic bearing problem, Through the simplification of the geometric model of a single oil pad to derive the effective bearing area of a single oil pad, then establish its mathematical model, for the following to prepare for the simulation of heavy hydrostatic bearing, and through the simulation of heavy hydrostatic bearing, get the input under the condition of unchanged, with the constant improvement of the speed, the change of heavy hydrostatic bearing pressure field. Results show that the feed quantity under the condition of unchanged, with the constant improvement of the speed, start from the center of the biggest oil cavity pressure peak around gradually diminishing, isobar and high oil and shape of cavity shape basically the same. Numerical calculation results reflect the inside of the bearing pressure distribution, the simulation results for the engineering practice the bearing oil cavity structure optimization design provides a theoretical basis.

Abstract: A new non-contact liquid bearing, which utilizing traveling waves, is developed in this paper. The developed bearing is designed in an octagon shape where series of piezoelectric actuators are placed between a rigid support plate and the elastic thin bearing surface around the circumference and in the radial direction. The driving apparatus for the developed bearing is implemented based on DSP and voltage amplifiers. The liquid film force induced by traveling waves is confirmed by experiments which prove the feasibility of the developed bearing.

Abstract: Under the condition of cutting speed 10-300m/min, rake angle -10°、0°、10°and cutting depths 0.05mm、0.1mm and 0.2mm, the experiment study of adiabatic shear serrated chip and surface roughness are carried out. The influence of cutting condition on serrated chip is analyzed through the metallographic observation of obtained chip. By the measurement of finished surface, the influenc of cutting condition and adiabatic shear on surface roughness is also investigated. The rusults show that the reason lead to serrated chip in high speed cutting of Ti6Al4V is adiabatic shear, not the periodic fracture.The adiabatic shear serrated chip is easier appear and the degree of segment is more large under the condition of higher cutting speed, larger cutting depth and smaller rake angle. The surface roughness is smaller when the cutting speed is higher, cutting depth is larger, and rake angle is smaller.

Abstract: In this work, cutting experiments were carried out on titanium alloy Ti6Al4V by using polycrystalline diamond (PCD) tools to investigate the effects of the tool geometries and cutting parameters on machined surface roughness. Experimental results show machined surface roughness decreases with increases in the flank angle, tool nose radius and cutting speed within a limited range respectively, and begins to increase as the factors reaches to certain values respectively. And machined surface roughness decreases with increases in feed rate and cutting depth respectively.

Abstract: According to the principle of ultrasonic vibration turning, the first step is to study different position changes of surface roughness with cutting parameters under ultrasonic vibration turning of slender shaft by the test of single factor, and determining the extreme position of surface roughness with the slender shaft changes in different cutting conditions. The second step is to study the influence of cutting parameters on the overall average surface roughness of work piece under ultrasonic vibration turning of slender shaft by orthogonal test design, and compared with the conventional turning. The experimental results show that ultrasonic vibration turning slender shaft processing can significantly improve the surface roughness. At the same time, the influence laws of cutting parameters on the surface roughness are investigated, and finding out the optimal cutting experimental parameters. Key words: slender shaft; ultrasonic vibration turning; surface roughness; orthogonal test design.

Abstract: Existing research on machined surface topography, only consider its response to vibration or wear certain factors, both vibration and wear impact on machined surface topography exist ambiguity and uncertainty, it cannot solve the design conflicts of machined surface topography. For this, this paper analyzes blade installation error, tool wear, vibration and deformation to reveal effects of tip space trajectory, build a three-dimensional model of machined surface topography in simulation, extract its characteristic parameters, by simulation of different amplitudes and wear, found that axis amplitude is a key factor affecting surface residual height, flank wear affects contour distribution distance significantly, by specimen milling experiments, use vibration measuring instrument and ultra-depth microscopy to obtain vibration, wear characteristics and machined surface topography parameters under different cutting parameters, then use the gray system theory to get correlation analysis of the test data, results showed that the influence of tool wear on machined surface topography is prominent than tool vibration.

Abstract: Surface roughness has a significant effect on the performance of machined components. In the present study, a total of 49 end milling experiments on AISI H13 steel are conducted. Based on the experimental results, the signal-to-noise (S/N) ratio is employed to study the effects of cutting parameters (axial depth of cut, cutting speed, feed per tooth and radial depth of cut) on surface roughness. An ANN predicting model for surface roughness versus cutting parameters is developed based on the experimental results. The testing results show that the proposed model can be used as a satisfactory prediction for surface roughness.