Feng Jun Chen

Material Removal Mechanism in Vibration-Assisted Magnetic Abrasive Finishing

This paper proposed a viewpoint to explain why vibration assistance may increase material removal rate (MRR) in vibration-assisted magnetic abrasive finishing process. A series of experiments on vibration-assisted finishing have been carried out. On the basis of these experiments, the finishing characteristics are represented summarily. It was shown that the increase in material rate is mainly due to an increase in material removal per unit working distance.

A Novel Orderly Arrangement Method Controlled by Magnetic Field for Diamond Abrasives of Grinding Wheel

In traditional manufacture of grinding wheel, a key problem is the randomly arrangement of the diamond abrasives, which results in randomly distribution of surface roughness. In this paper, through controlling the magnetic field during the forming process of the grinding wheel, arrangement of diamond abrasives is orderly to obtain a more orderly surface roughness. The forming process of diamond fine grinding wheel is studied under magnetic field controlling. The grinding experiment for aspherical mold was carried out on the tungsten carbide YG8 and the surface quality after grinding was also analyzed

Numerical Simulation on Two-Step Isothermal Glass Lens Molding

Glass lens molding is an effective approach to produce precision micro aspheric glass lens at high efficiency. In this paper, a new two-step isothermal glass molding process was proposed. The mechanisms of new molding process were analyzed. Finite element simulation was conducted to analyze the key factors such as the pressing load, die damage, molding time and residual stress of lens during the traditional molding and the two-step isothermal molding. The results showed that the two-step isothermal glass lens molding process may decrease residual stress and improve stress and strain distribution. Furthermore, prolong the service life of die.

Modeling and Computer Simulation of Grinding for Ball-End Milling Cutter with Equal Normal Rake Angle

In this paper, a new mathematical model and grinding method of ball-end milling cutter are proposed, based on the orthogonal spiral cutting edge curve. The movements of grinding wheel and ball-end milling cutter are presented while grinding rake face. In order to grind conveniently and avoid interference, a conical wheel is also designed and employed to grind the rake face of ball-end milling cutter on a grinder. In order to improve the machining characteristics of ball-end milling cutter, the model of rake face with equal rake angle is established. The software of ball-end milling cutter is developed to design and optimize different shapes of rake face. Furthermore, the simulation analysis on rake face with equal rake angle is carried out to confirm the validation of the mathematical models.

Effects of Permanent Magnet Excitation on Material Removal Rate in Area Taking Magnetorhelogical Finishing

In this paper, a novel area taking MRF process using permanent magnet as excitation was proposed. Four types of permanent magnet configurations were considered. Polishing experiment was conducted. Effects of different permanent magnet configurations on material removal rate (MRR) were discussed.

Influences of Model’s Shape on Molding Time in Glass Molding Press

Optical glass is widely used as the most important material in optical field in recent years. Glass molding press (GMP) has been employed as a promising technique to manufacture optical components in mass production. Heating time and annealing time are the key factors which influence the production cycle. In this paper, an effective method of improving the heating or the annealing effectiveness is to increase the area exposed to the cooling or hot nitrogen by means of adding slots. In the same condition, four models with different slots were built. Based on the theoretical analysis of glass heating and annealing property in the molding process, finite element simulation was carried out. The results showed that the model with slots may decrease the heating and annealing time.

Nozzle-Type ELID Grinding Characteristics of Cemented Carbides

This paper reports a systematic investigation of a nozzle-type ELID grinding characteristics of cemented carbides. Two groups of experimental scheme were carried on by using fine grain cast iron diamond wheel and nozzle-type ELID grinding apparatus. The grinding forces were measured by a dynamometer and the ground surfaces were characterized using scanning electron microscopy (SEM) and atomic force microscope (AFM). The influences of electrolytic and grinding parameters on grinding force were discussed. The material removal mode and micro-morphology characteristics were also analyzed.

Error Compensation in One-Point Inclined-Axis Nanogrinding Mode for Small Aspheric Mould

A compensation method was proposed for correcting wheel setting error and residual form error in nanogrinding of axisymmetric surfaces. In this method, profile data from on-machine measurement were used to obtain the setting error of grinding wheel, as well as the normal residual form error. Compensation model of single-point inclined-axis grinding was built up for generating new compensation path. Grinding test of aspheric tungsten carbide mould was conducted to evaluate performances of the compensation method. A profile error of 182 nm (peak to valley) and average surface roughness of 1.71 nm were achieved. These results indicated that the form error compensation method may significantly improve form accuracy of ground surface.

A Novel TEM Sample Preparation by Using Micro Magnetorheological Finishing

A novel TEM sample preparation method is proposed in this paper, which utilizes magnetorheological finishing to thin TEM sample. It can effectively reduce subsurface damage caused by mechanical lapping. A magnetorheological polishing tool is designed to meet TEM sample thinning requirements. Thinning testis conducted on Φ3mm single crystal silicon. Polished surface is observed by using transmission electron microscope, and high-resolution microscopy image of single crystal silicon can be achieved.

Effects of Magnetic Fluid on Machining Characteristics in Magnetic Field Assisted Polishing Process

Magnetic characteristics of three magnetic polishing fluids such as magnetic fluid (MF), magnetorheological fluid (MRF), and magnetic compound fluid (MCF) under magnetic field are experimentally investigated and analyzed. Their magnetic cluster structures under action of magnet field are observed, and their magnetic cluster models are established. Magnetic flied assisted polishing experiments for tungsten carbide are developed used these three kinds of magnetic fluids, material removal and surface roughness are respectively measured. At last, the machining characteristic of three magnetic fluids are contrasted and discussed according to experimental results.