Papers by Author: Dian Rong Luan

Abstract: Metal bonded diamond grinding wheels are very important for precision grinding operations of hard and brittle materials especially like ceramics or cemented carbides. But the trueing and dressing problem has affected its wide use. In this paper, a new EDD (Electrical discharge dressing) device was developed for the dressing of metal bonded diamond arc grinding wheels. The EDD experiments were carried out with the new dressing device. The influence of dressing parameters on the dressing efficiency and precision was studied. Experimental results shown that the increase of pulse period and duty period helped improve the dressing efficiency in a certain range. The higher electrical parameters could get better dressing efficiency. The detection results revealed that the error of the arc profile after EDD could reach to around 3μm. mazhaokai2014

Abstract: TN85 cermets is one kind of particle reinforced metal matrix composites, which is high hardness, good wear resistance, and bring great difficulties in processing, so it is necessary to study the processing performance. During the test on ELID grinding TN85 cermets, it is found that plastic removal is the main ways during grinding TN85 cermets materials. The powder particle size of W2.5 diamond wheel is successfully used in full removal of TN85 cermets plastic, the surface roughness value of rms: 16.81nm and Ra: 12.52nm. The results showed that: ELID grinding wheel with diamond powder technology can be used in ultra-precision machining TN85 cermets.

Abstract: Concave aspheric surface with small curvature radius is difficult to fabricate by most of existing technologies. Ultrasonic- magnetorheological combined finishing (UMC) is a new technique for the ultraprecision machining of aspheric surfaces, especially for the ultrasmooth surfaces machining of small-radiuses concave surfaces and freeform surfaces. According to the characteristics of rotary symmetrical aspheric surface, path algorithms for UMC finishing have been developed. Propose and compare two kinds of polishing dwell time algorithms, and the derivation process and computer simulation result of the algorithms was also presented. The experiments using the control algorithm have been conducted, and the efficiency of algorithm is proved by experimental results.

Abstract: The traditional ELID Grinding Technology has many limitations in grinding small diameter hole and spherical face. As a solution, a new method for ELID grinding - the fourth generation ELID Grinding Technology, ELID IV, is presented in the recent research. To serve the industrialized application of ELID IV, a series of experiments were performed to reveal principle of ELID IV. Results of these experiments indicated that: (1) electrolyse function is enhanced obviously when the workpiece is connected to the positive pole of the power supply using 45 steel as the material of test piece; (2) the relationship between the effect of electrolysis and the electrode gap is studied by using the 120 # Rail Based grinding wheel on the cemented specimens carbide for electrolytic grinding, and 1mm is determined the best electrode gap.

Abstract: A computational fluid dynamic (CFD) model for submersion jet has been developed to investigate the hydrodynamics in nanoparticle colloid jet machining with small diameter nozzle about 0.21mm. With this model, the fluid field characteristics and pressure distributions in the system are computed under the condition of vertical injection and aslant injection when jet pressure is 4MPa. The corresponding material removal experiments in nanoparticle colloid jet machining have been done to validate the rationality of the CFD model. And the simulated data are in good agreements with the experimental results.

Abstract: A new ultraprecision machining technology for KDP crystals, deliquescent polishing technology for KDP crystals, is presented. On the basis of analyzing the definitions of deliquescence, the dissolution experiment of KDP crystal’s surface was conducted. Through the experiment, the material removal mechanism in deliquescent polishing of KDP crystals is proposed, and the deliquescent polishing device for KDP crystals is described. Based on the material removal mechanism in deliquescent polishing of KDP crystals, the deliquescent polishing experiment of KDP crystal was carried out, the experimental result has verified the validity, feasibility and effectiveness of the material removal mechanism.

Abstract: 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.

Abstract: Concave aspheric surface with small radius is difficult to be fabricated by most of existing technologies for optical manufacture. Ultrasonic- magnetorheological compound finishing (UMC finishing) is a new technology for the ultra-precision machining of concave aspheric surface with small radius and freeform surface. The principle and experimental deviece used in UMC finishing are introduced. Main technological parameters in UMC finishing include the magnetic flux density, the gap between the polishing tool head and the workpiece, the rotational speed of polishing tool head and so on. The technology experiment of UMC finishing for optical glass K9 is conducted, and the influence of main technological parameters on the material removal rate has been studied by analysis of experimental results. The analysis of removal profile curve of UMC finishing spots prove that the material removal function of UMC finishing meet the surface error convergence requiement in computer control precise optical surface machining. The part surfaces after UMC finishing are measured by an Atomic Force Microscopy (AFM), and the surface roughness Ra is 1.591 nm after polishing for 10 min. It is demonstrated that the polishing capability of the technology is excellent.

Abstract: A nanoparticle colloid jet machining system has been developed for polishing ultra smooth surface of brittle materials. Interaction between nanoparticles and work surface in nanoparticle colloid jet machining has been given, and the theoretical dependence of the material removal rate with various important process parameters of the nanoparticle colloid jet machining have been investigated through material removal experiments. Some material removal results of nanoparticle colloid jet machining show that it is possible to obtain removal rates of one nanometer level per minute for glass surfaces with appropriate machining process parameters. A K9 glass surface was polished for obtaining ultra smooth surface. The surface roughness value of atomic force microscopy (AFM) observations is under 1nm Rms.

Abstract: The paper presents a newly developed optical polishing method, Ultrasonic-magnetorheological compound finishing (UMC finishing). The mechanism of UMC finishing is introduced in the paper. Experiments are carried out to study the surface quality of the optical glass K9 in UMC finishing. The result shows that the surface roughness Ra of the optical glass is 4.0nm, which is measured by the profile meter. The rules of surface roughness for optical glass by the main processing parameters are also acquired by the experiments. The study will be the basis for the further study of UMC finishing technology.