Materials Science Forum Vols. 697-698

Abstract: The developments of edge chipping for engineering ceramics are analyzed. An edge chipping experiment under static load is adopted to study the fracture process of edge chipping. The results show that the fracture processes of edge chipping under different edge distances are similar, which can be divided into four stages based on load-displacement curve. There is obviously Kaiser Effect during the fracture processes of edge chipping. Counts, average frequency, RMS, duration, amplitude and inverse calculation can be used to describe the process of edge chipping for engineering ceramics. Amplitude, duration and average frequency become highly active on the eve of fracture, which can be regard as the omens of edge chipping and used to predict the fracture of edge chipping.

Abstract: Dynamic analysis and modal test were conducted on a vertical grinding machine. The mathematical model of joint surface parameter identification between the bed and the column was established in CAD/CAE integrated environment. Based on the results of dynamic analysis and modal test, the parameters of joint surface were identified and the finite element model was accurately created. Then, the weak bodies of the original machine were improved. According to the finite element analysis of the improved machine, the performances of the new machine were better than the original machine.

Abstract: In this paper, a series of experiments were carried out on normal and high speed milling of a new damage-tolerant titanium alloy. The effects of milling parameters on cutting force and cutting temperature were investigated. The tool life of three commonly used cutters, such as WK10, WMG40 and WXN15, were studied. Result shows that the tool life of cutter WXN15 was the longest one when using the same flank wear VB as a standard, and cutter WK10 had a longer too life than cutter WMG40. Thus cutter WXN15 was the most suitable cutting tool to machining TC4-DT, and cutter WK10 was better than cutter WMG40.

Abstract: Through the odd factor grinding experiment of microwave ferrite, the tangential and normal force were measured in different grinding parameters (wheel speed, feed rate, cutting depth, wheel size). According to the variation of the tangential force and normal force in different grinding parameters after grinding, the reasonable grinding parameters of microwave ferrite were explored. The results demonstrated that the grinding force had different variations in different grinding parameters. These could be the reference and guidance for the future processing of microwave ferrite materials.

Abstract: Identification of workpiece material constitutive parameters for their application in the simulation of metal cutting process has been a hot research spot for long. This paper proposes a methodology to address this problem using orthogonal cutting tests and Genetic Algorithm (GA). First, an analytical model which calculates the dynamic characteristics occurring in the primary shear zone is introduced; then, orthogonal cutting tests are carried out, to record the following mechanical characteristics with the analytical model: shear stresses, shear strains, strain rates, cutting temperatures; afterwards, GA is employed to obtain the constitutive parameters from these characteristics; at last, the finite element method (FEM) simulations of the cutting tests are performed to evaluate the predictive accuracies of the obtained parameters. In this paper, a Japanese brand steel SCM440H is used as the workpiece material, and the simulation results of its constitutive parameters show good agreements with the experimental data, which renders the feasibility of the proposed methodology.

Abstract: The surface roughness and surface texture feature both are the key factors to evaluate the ground ceramics surface. The Gray Level Co-occurrence Matrix (GLCM) is introduced to extract and analyze the texture features of ground surface, in order to discover the relationship between texture features and roughness, and predict the roughness of ground ceramics according to the defined texture parameters. Four matrices about different sampling orientations are built up after the sampling offset and total gray levels are determined. By analyzing the correlation about every two features, Contrast, SS and ASM are selected to characterize the texture information of machined surface. Finally, the paper reveals the linear variation laws between R_a, R_y, S, t_p and above features. The grounding quality of ceramic products also can be roughly estimated on the ground of that.

Abstract: This paper was dedicated to elucidate an investigation of abrasive wear and surface topography of Titanium alloy TA15 on dry grinding with zirconia alumina belt. In the investigation, experiments were performed on milling machine XS5040 equipped with assembled belt grinding device. The wear abrasive, surface morphology of machined belt in different phase were analyzed using 3D viewer microscope. The results show that the wear of belt abrasive is mainly steady attritions wear since zirconia alumina belt was stable on dry grinding. At higher grinding force, the abrasive was found to undergo dislodging prior to being gradually worn. So zirconia alumina belt has excellent performance in the dry grinding titanium alloy.

Abstract: After the processing of a clock dial, the precision dimension and uniform distribution of the tool-trace pattern on the dial surface have a connection with luster image and attractiveness, which in turn would have an impact on the additional values and prices for a clock. Through a systematic investigation among the lathe structure, process parameter and cutting-tool geometry in advance, the total results indicated that the rigidity of the lathe structure and the precision of the slider movements are excellent and they had only a little effect on the surface-related quality for a dial face turning. Hence, the combination of process parameter and cutting-tool angle becomes more essential. End face turning simulation and experiment of a copper alloy were thus conducted in this paper, and the chip formation process and machined surface-related quality are investigated, respectively. The effects of cutting tool geometry and process parameter on the results of chip formation, surface rough, tool-trace pattern and luster uniformity are investigated, and these results are also compared with each other. The results show that when larger clearance and rake angles used in conjunction with a lower feed rate, no matter how much cutting speed was enhanced, the surface-related quality of a dial surface is not good. However, when these two larger angles used combined with a larger feed rate, the quality of a dial surface would slightly be improved. By using smaller clearance and rake angles along with the higher feed rate and cutting speed would obtain a better surface-related quality with uniform luster and attractiveness.

Abstract: The deflection of Aluminum alloy thin-wall workpiece caused by the milling force leads to additional machining errors and reduces machining accuracy. In this paper, a set of experiments of milling thin-wall workpiece were carried out to study the deflection of thin-wall workpiece. The workpieces, with different types of material and different thicknesses, were machined on CNC machining center. The deflections of workpiece were measured by a three-coordinate measuring machine. Effects of Aluminum alloy material and thickness on deflection are discussed based on the experimental data.

Abstract: This paper deals with an investigation of surface integrity of Ti6Al4V alloy with zirconia alumina and SiC belts. The experiments were conducted under dry grinding environments in milling machine XS5040 equipped with belt grinding device. Microcosmic geometry parameters were measured with TALYSURF5 instrument, the surface morphology machined workpiece and the phase structure was analyzed using 3D viewer microscope, surface hardness for ground surface was measured by HXS-1000A instrument. The results show that surface quality maintain better level during a long period, the grinding affected zone was small(≤15μm), zirconia alumina belt has excellent performance than SiC belt during dry grinding Ti6Al4V alloy.