Papers by Author: Jian Wu Yu

Abstract: Silicone oil based magnetic compound fluid was prepared to polishing stainless steel in this paper. The new fluid consists of nano-sized magnetite particle, micro-sized diamonds, micro-sized iron particle and α-cellulose. The characteristics of the fluid were analyzed. The length and quality of the magnetic cluster in the compound fluid was observed under a magnetic field. Polishing experiment of stainless steel was conducted using the silicone oil based magnetic compound fluid on an inclined polishing finishing device. The micro morphology of the stainless steel’s surface was measured. The results showed the surface quality was improved remarkably and the final roughness of the surface was Ra (Average roughness) 0.020μm.

Abstract: An extracting method of normal residual error from a ground profile was proposed in this paper. Original measurement data was re-processed for obtaining an actual ground profile in an on-machine contact measurement system. The robust Gaussian regression filtering and NURBS fitting methods were employed to filter and fit these discrete data for getting the accurate realistic ground profile. By utilizing iterative partitioning algorithm, the normal residual error could be accurately obtained between the actual ground profile and the ideal one. Measurement data achieved from grinding experiment of aspheric mould were dealt with. After form error compensation grinding, the difference between normal residual error and original reached 40 nm in stead of initially 140 nm.

Abstract: Stainless steel; Aspheric mould; Ultra-precision turning; Magnetorheological polishing Abstract. The ultra precision turning and the inclined-axis type of magnetorheological polishing were introduced for the small aspheric mould of stainless steel. The method was based on the principle of two kinds of processing methods, and the processing feature of stainless steel material. Firstly, the ultra-precision turning was employed to shape aspheric surface rapidly and obtain a relatively good surface. And then, the inclined-axis type of magnetorheological polishing as the final finishing was used to decrease sub-surface damage to obtain better precision. Several of experiments were carried out, the experimental results show that surface roughness can be achieved for Ra 0.0073μm.

Abstract: 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

Abstract: Based on the magnetic field controlling principle, a new manufacturing method and experimental research of fine grain diamond grinding wheel were introduced. The magnetic particles could form spatial chain structures under magnetic field which can make abrasives distributed uniformly within the mold. Therefore, small surface roughness can be obtained when grinding. The manufacturing and dressing of fine grain diamond grinding wheel based on magnetic field controlling (acronym FGDWMC) were introduced. The comparison grinding tests between the magnetic field controlling and nonmagnetic field controlling of wheels were studied. The grinding experiment result showed that the surface roughness was better after being machined by FGDWMC, and it was improved by about 20nm.

Abstract: With the rapid development of opto-electronics communications, optics, aerospace and other industries, ultra-precision aspheric glass lenses are widely used in middle/high-grade optical opponent because of its high resolution and imaging quality. To achieve ultra-precision molding pressing of micro-lens, ultra-precision mold must be fabricated firstly. In this paper, some key new technologies were proposed for fabricating ultra-precision mold of small-size aspheric optical lens. A method of finite element simulation was employed to predict mould pressing process of the glass lens for correcting molds and improving the formation efficiency. An ultra-precision inclined-axis grinding and error compensation technology was also used to improve form accuracy of micro lens mold.

Abstract: The basic principles of ultrasonic transducer and ultrasonic elliptical vibration polishing are investigated. A new kind of single-incentive ultrasonic transducer is designed, and the finite element simulation is conducted, a polishing device is developed based on the ultrasonic elliptical vibration. The polishing experiment is adopted to polish a tungsten carbide mold with the diameter 5cm. The experimental result shows that the tungsten carbide mould surface roughness changes from the original 0.026μm to 0.017μm.