Nanoparticle colloid hydrodynamic cavitation jet polishing (HCJP) is a supersmooth surface machining technology that utilizes the interface reaction to remove material from workpiece, applying the cavitation effect to improve the processing efficiency. In this paper, a plototype equipment of HCJP is introduced and the experiment of HCJP and common jet polishing has been done. The experiment results indicate that in both cases, the processed area presents the orbicular structure of “W” shape when the angle of jet and horizon is 90°; the position that has the best surface quality located on the annulus of processing region where the most material removed. Compared with the common jet polishing, the surface quality processed by HCJP that uses the swirling jet is better. In processing experiment of HCJP, the supersmooth surface with roughness of Ra 0.758nm is obtained.

This paper presents an experimental and theoretical study of surface generation in ultra-precision grinding of hard and brittle materials. The study takes into account material properties, the relative vibration between the grinding wheel and the workpiece, machining parameters and the phase shift of the grinding process.The Taguchi approach is employed to study the influence of machining parameters on the surface quality and shows the feed speed and rotational speed of the workpiece are key factors. Experiments have been conducted to study individual variable and the results further show that the feed rate and the cross-feed distance have significant effect on the surface generation. It is found that the spirals around the central area of the workpiece are the primary mechanism for surface generation, which originates from the synchronous relative tool-work vibration. The integral part of the ratio of the rotational speed of the grinding wheel to rotational speed of the workpiece determines the number of the spirals and its fractional part controls the spiral geometry. A theoretical model for predicting the single spiral generation has been developed to explain the accumulation of the phase shift and the geometry. The changeable feed speed near the end of grinding is also modelled, revealing the approximate straight lines around one circle in the central region. The simulated results indicate the theoretical models and the ground surfaces are in close agreement. The scallop-height model is developed to calculate the influence of phase shift on surface quality and it is found that the phase shift near the medium value can effectively improve surface quality. Finally, a comparison for different surface generation mechanisms in grinding mould Steel, tungsten carbide (WC) and reaction bonded silicon carbide (RB-SiC) is investigated. It is interesting to note that the Spanzipfel effect contributes to the surface generation not only on ductile materials such as mould Steel but also on brittle materials such as WC and RB-SiC. The Spanzipfel effect is most significant in grinding mould Steel. For WC and RB-SiC, the ground surface contains both ductile region and brittle region in form of micro fracture.

We developed a nanoparticle colloid jet machining to fulfill the requirement for ultrasmooth surface in terms of the studying on micro structure of work surface, the high surface energy and intense adsorption of SiO2 nanoparticle. In this paper, three types impact in nanoparticle colloid jet machining have been analysed and the atom removing model has been founded based on the physical chemistry theory of solid surface and interface. The factors which may influence the nanoparticle colloid jet machining quality (such as the diameter of nanoparticle, colloid jet velocity and dynamical viscidity) have been studied to provide theoretical support for further studying in nanoparticle colloid jet machining.

The characteristics and principle of deliquescent polishing technology for potassium dihydrogen phosphate (KDP) crystals are introduced, and the performance requirements of deliquescent polishing fluid for KDP crystals are proposed. The main components of the deliquescent polishing fluid for KDP crystals were selected according to these performance requirements. Through uniformity experiment, stability experiment and fluidity experiment, uniformity, stability and fluidity of deliquescent polishing fluid for KDP crystals prepared using the selected components were tested. Through deliquescent polishing experiment of KDP crystal, polishing performance of deliquescent polishing fluid compounded using the selected components was tested. The material removal rate of the KDP crystal in the deliquescent polishing experiment was 6.03μm/min, and the surface roughness of the KDP crystal after deliquescent polishing was 4.857nm. The experimental results show that the compounded deliquescent polishing fluid for KDP crystals has good polishing performance and can reach the requirements.

The factors influencing surface quality for brittle materials is theoretically analyzed during ultra-precision grinding. Grinding experiments of brittle materials are carried out. The results show that the average abrasive grain size of the diamond wheel has a main influence on the surface quality, and the influence of the wheel speed and feed rate is secondary. In the case of s =1200m/min, f=0-20 µm/rev, and a p =0.1-10µm, only when the average abrasive grain size of the diamond wheel is less than 10µm, the super-smooth surface, for which Ra is 6.200nm and rms is 8.201 nm, can be obtained under grinding in the ductile mode.