Papers by Author: X.H. He

Abstract: To evaluate the characteristics of semi-fixed abrasive plate (SAP), several parameters and relevant measurement methods are developed. The characteristic parameters include shore hardness, compression ratio, resilience ratio and shear strength. Five semi-fixed abrasive plates are manufactured with different bond concentration. The test results of five characteristic parameters of the SAP show the shore hardness, resilience ratio and shear strength increase, and compression ratio decreases with the bond concentration increasing. This test can provide instructive guides to the manufacture of SAP which can fit different occasions by changing the concentration of adhesives.

Abstract: To study the lapping process and sphere-shaping mechanism of WC-Co cemented carbide ball under eccentric dual-rotating (EDR) V-groove lapping mode, the research center designs EDR V-groove lapping machine. This paper analyses sphericity of WC-Co cemented carbide balls after the lapping. During the lapping process, the diameter variation is measured every one hour. The diameter of ball is usually reduced 0.05mm every hour, which is more than the dual rotating plates(DRP) lapping mode, and the experiment is totally done 9 hours, the error of sphericity can be controlled around 0.005mm in the last, so the EDR V-groove lapping mode is more suitable for lapping of the WC-Co cemented carbide ball in roughness and semi-finishing process. In order to compare the material removal rate between DRP lapping mode and EDR V-groove lapping mode, the balls are also lapped under DRP lapping mode.

Abstract: In this paper, the batch processing of Φ35mm WC-Co cemented carbide balls used in one-way value is studied by rotated dual-plates (RDP) lapping machine. On the basis of this innovated equipment, the processing parameters, including abrasive grain, rotating velocity and load, are changed legitimately in experiment. The experimental results show that the abrasive grain is used from big to small, while the rotating velocity and load are gradually reduced in order to improve the uniformity of lapping trace distribution on the ball surface in batch processing. Finally the rational course and parameters are defined, these WC-Co cemented carbide balls satisfy the products’ final demand which means the sphericity error (Rnd) is less than 1μm and the roughness of surface (Ra) is better than 50nm. Because of the feasibility, the precision of final WC-Co cemented carbide balls improves and can be applied in one-way value used in oil exactor.

Abstract: Semi-fixed abrasive is a novel abrasive. It has a ‘trap’ effect on the hard large grains that can prevent defect effectively on the surface of the workpiece which is caused by large grains. In this paper, some relevant experiments towards silicon wafers are carried out under the different processing parameters on the semi-fixed abrasive plates, and 180# SiC is used as large grains. The processed workpieces’ surface roughness Rv are measured. The experimental results show that the surface quality of wafer will be worse because of higher load and faster rotating velocity. And it can make a conclusion that the higher proportion of bond of the plate, the weaker of the ‘trap’ effect it has. Furthermore the wet environment is better than dry for the wafer surface in machining. The practice shows that the ‘trap’ effect is failure when the workpiece is machined by abrasive plate which is 4.5wt% proportion of bond in dry lapping.