Papers by Author: Gang Ya

Abstract: In the paper, a new method of using rotating magnetic field generated by a stator of alternative electromotor to finish the inner surface of tube-type workpiece is proposed. Force and movements of magnetic abrasive are analyzed. The finishing mechanism is analyzed and the sliding, friction and scratching between magnetic abrasives and the workpiece inner surface may be main factors of material removal as the non-mechanical relative motion is produced.

Abstract: Ultrasonic vibration can reduce honing forces efficiently. As the honing wheel can be washed by ultrasonic cavitations of cooling liquid, its jams are decreased and the higher honing efficiency has obtained. Therefore, the combination of ultrasonic machining and gear honing is a method for gear fine machining with its wide application future. In the paper, to improve the rigidity, the ultrasonic vibration system adopted the structure of double supports as traditional honing machine, so the horn is symmetric. The machined gear was simplified into a circular thin plate with diameter of its reference circle and the horn was treated as its half as the symmetry; the frequency equations of the transformer were derived according to stress match under the condition that the half horn and plate of the transformer were considered at the same time; the frequency equations were derived based on the boundary conditions. Then the design parameters of the transformer were obtained as the frequency equation was solved computationally and expanded to the whole horn. The displacement, stress of the transformer was solved, too. Finally, the vibration mode of the transformer was analyzed by ANSYS. The results of theoretical and ANSYS analysis is consistent, which means the theoretical model and analysis method are correct.

Abstract: In the process of the ultrasonic machining, the machining efficiency is affected directly by material removal rate. In the paper, the material structure deformation under abrasive impacting is simulated by the LS-DYNA3D software, and the stresses occurring are analyzed numerically. In addition, the effects of some machining parameters on the amount of the material removal are investigated by the experiments.

Abstract: In this paper we discuss the temperature dependence and its effect on surface roughness. In abrasive flow machining (AFM) process the temperature of media rises drastically due to procedure of being sheared. To examine the effect of media temperature on surface roughness, an experiment system with the functions of controlling, measuring and recording temperature is set up. The variable trend of media temperature is revealed during AFM. Experiments are performed at different temperatures. Experimental results show that the media at high temperature results in less improvement in surface roughness. Therefore the media can have good machining performance in the first few cycles and the media temperature rise rapidly. Finally we conclude that the best workable temperature should be below 25 °C during the AFM.

Abstract: Ultrasonic vibration can reduce honing forces efficiently. As the honing wheel can be washed by ultrasonic cavitations of cutting fluids, its jams are decreased and the higher honing efficiency has been obtained. Therefore, gear honing combined with ultrasonic machining honing is a method for gear finish machining with its wide application future. Ultrasonic-assisted honing of gears is firstly proposed, its machining devices are manufactured based upon the design parameters derived by four-terminal network principle. Experiments of gear honing show that the machining traces on the tooth flanks in ultrasonic and traditional honing are different. The ultrasonic honing can produce a better tooth surface roughness (Ra 0.45 μm) than one obtained conventional honing (Ra 0.72 μm).

Abstract: Ultrasonic vibration can reduce honing forces efficiently. As the honing wheel can be washed by ultrasonic cavitations of cooling liquid, its jams are decreased and the higher honing efficiency has obtained. Therefore, the combination of ultrasonic machining and gear honing is a method for gear fine machining with its wide application future. However, the gears with big diameter and thickness machined by ultrasonic honing are special loads, which influence the machining frequency of vibration system heavily. Hence, the horn and gear must be considered at the same time while designing the vibration system. In this paper, the frequency equations are derived according to stress match, wherein, the gear is considered as a thin disc and catenary horn is adopted. Then the influences of vibration of transformer that consists of horn and gear are investigated with the variety of the horn length and the machining frequency. The theoretical analysis shows that the resonance frequency of the horn and detune frequency of transformer have the different value. The results are proved by FEM, too.

Abstract: In the paper, a new method of using rotating magnetic field generated by a stator of alternative electromotor to polish the inner surface of tube-type workpieces is proposed; a finishing device using the stator construction and inverter is designed; the finishing mechanism is analyzed and experiments are carried out. Experimental investigations show that filling amount of magnetic abrasive influences the surface roughness of workpiece directly and have an optimal value. The higher magnetic conductivity is, and the finer finishing effect is. The attraction force of magnetic particles depends on intensity of magnetic induction directly and has the optimal value. The higher the rotation speed is, and the lower the value of surface roughness. Under the optimal experimental condition, the new method can reduce the value of surface roughness more than 2 grades. Therefore, this technique has prospective application future.

Abstract: In the paper, a new technology combining conventional CBN electroplating and thermal diffusion in vacuum to produce gear-honing-tool for hardened tooth is introduced. The two factors, such as planting CBN abrasives and combination between electroplating layer and matrix that can affect the quality of gear-honing-tool, are investigated. Experiments show that using suspension CBN abrasive electroplating combined with thermal diffusion in vacuum can ensure the quality of planting CBN abrasives of gear-honing-tool and obtain the semi-metallurgy binding layer between CBN abrasives and matrix that withstands the force of honing gears.

Abstract: The theory and effect of gear-honing are wholly different between electroplated CBN hard honing wheel and epoxy resinoid soft honing wheel. In the paper, through deeply analyzing the mechanical character and engaging situation of both plated CBN hard honing wheel and gear, the bending deformation, contact distortion and cutting depth are calculated at engaging point. At last, the manufacturing technology combining conventional CBN electroplating and thermal diffusion in vacuum to produce gear-honing wheels for hardened tooth is introduced. These are important to improve the machining accuracy and finish of hardened gear tooth surface.