Papers by Author: Zhi Xiong Zhou

Abstract: A test method for riveting assembly force, used in hub bearing unit assembly, was present in this study. Based on the test results, the influences of motion trajectory of rivet head, structure of rivet machine and feed rate of rivet head on axial force were analyzed. The corresponding improvement measures were proposed.

Abstract: The centrifugal force has great influence on characteristics of the turbine shaft. The changes of stress, diameter and natural frequency of the turbine shaft for self-developed micro-spindle for micro-cutting following with the rotational speed were studied by finite element (FE) simulation, which showed that stress, diameter of the turbine shaft and frequency of torsional vibration in elastic shaft coupling integrated with the turbine shaft caused by the centrifugal force increases almost linearly with increase of rotational speed and the higher the speed, the larger the increase. The frequencies of other vibrational modes were influenced by centrifugal force. Materials with good properties can improve characteristics of turbine shaft caused by the centrifugal force well.

Abstract: As sapphire is an important substrate material, stringent surface quality requirements (i.e., surface finish and flatness) are required. In order to acquire the higher material removal rate and the better surface quality of sapphire, the solid state-reaction were introduced in this paper; abrasive of SiO2 and SiO2 with mixing the MgF2 power were compared to polish sapphire. The result showed that abrasive of SiO2 with mixing the MgF2 can obtain higher material removal rate and better surface quality. The result of the pr

Abstract: Resin bond is one of the most widely bond used for manufacturing abrasive product. This review paper discusses historical perspectives on resin bond, there are different abrasive products which can be produced by using various types of resin bond such as modification of Phonetic resin and a new water-soluble resin. It is intended to help readers to gain a more comprehensive view on resin bond used for abrasive products and to be instrumental for research and development in producing abrasive products.

Abstract: Cup wheel grinding and etching pretreatment are widely used in complex coated cemented carbide cutting tools machining process. The two processes determine different surface properties due to various mechanical and thermal loads in grinding and complex chemical reaction in etching pretreatment. In this paper, the effect of the grinding wheel speed, the grinding feed rate and the etching time with the Murakami and acid solution on the residual stress and surface topography of coated cemented carbide cutting tools are investigated. After each process, the samples are characterized by scanning electron microscopy and X-ray diffraction. It is found that the grinding wheel speed has a significant influence on residual stress measured in the WC phase. Etching by Murakami generated smooth surface, which partly removed the near-surface residual stress quickly but cannot eliminate.

Abstract: Wire electrical discharge machining (Wire EDM) cutting of flexures for a rotary flexural bearing fabrication is developed. The results of FEA calculation and theoretical analysis show that one of the main factors affecting flexures’ machining is the weak torsional stiffness of the bearing cage, thus excessive deflections due to machining stress, heat generation and spark-induced vibrations may occur. To minimize flexure deflection during the machining process, a specially designed fixture is utilized. Other technical measures, including residual stress relief before and after Wire EDM cutting, reasonable cutting sequence planning, multiple-cutting (i.e., rough cut followed by several trim cuts) etc., are also adopted for cutting. Dimensional accuracy of ±5µm was obtained over the 150µm thickness for the bearing flexures, a variation of less than 3µm was achieved for the flexures of opposing sides, and surface roughness of better than Ra 0.3μm was obtained for the flexures of the entire bearing cage. These results show the validity of measures aforementioned.

Abstract: This paper presented a new transmission device for high-speed precision micro-shafting, which consists of an elastic shaft coupling and a collet, both which are integrated with the drive shaft, and a clamp ring, and meanwhile accomplished the detailed structure parameters design calculation by theoretical analysis and simulated computation with an application to an ultra-high speed micro-spindle, which shows the transmission device rational and feasible.

Abstract: In this paper, grinding wheel spindle of high precision CNC is researched. Mathematics - mechanical mode of dynamic balance of grinding wheel is established on the principle of rotor dynamic balance. New method of critical speed of grinding wheel is proposed, and verified by testing the reasonableness. And, dynamic unbalance of grinding wheel spindle of high precision CNC is studied on quality surface. These studies provide theoretical direction for balance speed range and the accurate level.

Abstract: In this paper, the variable speed grinding experiments at high speed have been studied systematically, and the method of improving the surface quality of high-speed grinding has been discussed on the basis of analysis of the chatter and the stability of the high-speed grinder. Through the variable speed grinding experiments at high speed, the vibration characteristics were measured by the vibration energy, and the power spectrum were analyzed by the maximum entropy spectral estimation of the vibration signals in time series. The results confirm that the chatter of high-speed grinding can be suppressed by the variable speed grinding to a certain extent.

Abstract: White light interferometer was employed to measure the surface topography of 60# and 120# alumina grinding wheel. The correlation of wheel topography and its performance was characterized through the three-dimensional (3D) surface characterization parameters of “Birmingham set”. Birmingham parameters were used to characterize the performances of grinding wheel, in items of grain density, grain shape and grain sharpness. The effects of sampling interval on the 3D surface parameters were analyzed and the optimal sampling interval was selected to calculate the 3D surface parameters.