Papers by Author: Jia Jie Chen

Abstract: To improve the sphericity and processing uniformity of precision ball, Simulations and analysis of the mechanism Position Deviation of Rotated Dual-Plates Lapping on precise Sphere, it can be indicated that mechanism Position Deviation (down plate axial deviation and down plate radial deviation) have little disadvantageous influence on sphericity and processing uniformity.

Abstract: Aluminum is a non-ferrous metal material which has excellent comprehensive performance. It has been widely used in many sectors. In this paper, plane abrasive machining is carried out for the aluminum. The quality of the Al specimen’s surface is compared after the semi-fixed and loose abrasive processing. The experiment proved that semi-fixed abrasive machining is better than loose abrasive in reducing surface roughness of Al-blocks. In the semi-fixed abrasive machining, the surface roughness of Al-block continued to drop and become stable after 40 minutes. It can prevent deep scratches on Al-blocks’ surface effectively and can get a mirror effect. The surface roughness can reach to Ra 22nm, Rmax 490nm, Rv 130nm. Its removal efficiency is also higher than loose abrasive machining. It is proved that semi-fixed abrasive machining can take the place of rough polishing processing.

Abstract: In order to get high precision balls used in oil exactor, Eccentric dual-rotating (EDR) V-groove lapping mode and Rotated dual-plates (RDP) lapping mode are applied for the batch processing of WC-Co cemented carbide balls of Φ35mm. After comparing two innovated modes, firstly EDR V-groove lapping mode is used in rough lapping stage for high efficiency, and then semi-finishing lapping stage, finishing lapping stage and polishing stage are carried out by RDP lapping mode. Through changing the processing parameters legitimately, including abrasive grain, adjustable rotating velocity and load, the rational course and parameters are defined, and WC-Co cemented carbide balls of Φ35mm satisfy the end products’ demand which means the sphericity is less than 1μm and the roughness of surface (Ra) is better than 50nm, so these balls can be applied in one-way hydraulic value used in oil exactor.

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: 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.