Gang Ya

Analysis of the rotary ultrasonic machining mechanism

Abstract In this paper, the movement of the abrasive particles in the tool tip of rotary ultrasonic machining is analyzed. The impact and grinding of the abrasive in the tool tip on the machined surface are considered as the main factors in the material removal rate. The crack propagation in rotary USM is investigated by using the theory of fracture mechanics. A mathematical model for the material removal rate is proposed in order to provide a theoretical basis for the analyzing of the process of rotary USM.

Study on machining mechanism of high viscoelastic abrasive flow machining for surface finishing

Abrasive flow machining is a pragmatic machining process used for part finishing. This article primarily focuses on the study of machining mechanism of high viscoelastic abrasive flow machining, with the aim to understand the relation among the abrasive media’s flow pressure, the material removal rate and the machining quality. The theoretical calculation models of the normal pressure on the inner surface of a circular tube and the wall sliding velocity are established based on rheology theory. The material removal rate of abrasive flow machining with a high viscoelastic abrasive media is derived. Numerical simulations with various machining conditions were conducted using the mathematical models proposed in this research and the obtained findings are discussed. The feasibility of these models introduced for high viscoelastic abrasive machining is also investigated and verified through actual experimental tests.

Research on System Design of Ultrasonic-Assisted Honing of Gears

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).

Temperature Dependence and Effect on Surface Roughness in Abrasive Flow Machining

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.

Study on Dynamical Characteristics of Catenary Transformer in Gear Honing

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.

Study of Finishing Mechanism for Internal Surface Using Magnetic Force Generated by Rotating Magnetic Field

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.

Mechanism Analysis of Ultrasonic Machining Based on Finite Element Method

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.

Theoretical Research on Gear-Honing and Manufacturing Technology with Electroplated CBN Honing Wheel

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.

Cutting Tool Run out Considered Cutting Force Estimation in Micro Milling Processes

This paper presents a method of estimating cutting forces of the tool by taking the tool’s run out into account during micro milling processes. The thickness of uncut chip is modelled based on the trochoidal trajectory synthesized from the rotational motion, the feed motion, and the run out of rotational micro tools. The strain gradient plasticity theory is then used in conjunction with the Johnson–Cook constitutive equation to calculate flow stresses, where the influence of the plough shear on the rake face and the elastic recovery on the flank face is considered. The calculated cutting forces using the proposed method for micro milling processes show a satisfactory agreement with existing experimental results.

Design of Monitoring and Controlling System for Aquaculture Based on Wireless-Embedded Technology

A parameter monitoring and control system is designed in this paper. Hardware is composed of the on-site data acquisition model and remotely display and operating model, which communicated through wireless technology. It monitors the aquaculture parameters (including temperature, PH and dissolved oxygen (DO) concentration) on-line, and water pump or air blower are controlled depended on the value of the parameters. Software is designed respectively for each model, temperature compensation is used in the control system. Experiments show that monitoring and control system for aquaculture had excellent effect, it could reduce investment and human capital in aquaculture production.