Papers by Author: Ju Long Yuan

Abstract: Deformation behavior; Aspheric surface; Finite element method; Contact area Abstract. Elastic deformation machining is a novel processing method for aspheric surface. In the machining process, the workpiece will deform and be in contact with the molded surface once load is applied. In this paper, a finite element model was built with Abaqus/CAE package to predict the deformation behavior of glass plate and some significative conclusions were obtained. The numerical simulation results show that the contact area between the plate and the mold is increasing with different pressure. Once the required pressure value is determined exactly, the glass plate can be deform and completely contact with the mold. The deformed shape of glass plate will completely contact with the mold at pressure p=100kPa. These conclusions have the positive significance for the applying of elastic deformation machining.

Abstract: Based on the hybrid combination of case-based reasoning and BP-neural network, process parameters intellectual decision strategy of function ceramics with high efficiency and precision chemical mechanical polishing (CMP) was proposed in this paper firstly. And then, referring to the technical manuals, experiences of engineering workers and experimental data, the process parameters database for function ceramics in CMP has been built with Microsoft software Access. On the basis of the above efforts, the process parameters intellectual decision support system for high efficiency and precision CMP of function ceramics has been developed by applying PowerBuilder software, which can realize the process parameters optimization, the surface roughness prediction and process parameters intellectual decision. Examples show that the prediction results are coincident with the experiments well.

Abstract: As sapphire is an important substrate material, stringent surface quality requirements (i.e., surface finish and flatness) are required. In order to acquire the higher material removal rate and the better surface quality of sapphire, the solid state-reaction were introduced in this paper; abrasive of SiO2 and SiO2 with mixing the MgF2 power were compared to polish sapphire. The result showed that abrasive of SiO2 with mixing the MgF2 can obtain higher material removal rate and better surface quality. The result of the pr

Abstract: The soluble filler in the newly developed metal bonded superabrasive tool named porous self-generation superabrasive tool (PSST) plays the most important role. To investigate the influence of filler material and its content on the mechanical properties, Zn, CaO, SiO₂ are employed as the soluble filler.Shear experiments and lapping experiments are carried out. It is found that the shear force of PSST with Zn is the highest, and declines little from 3.2 kN to 2.9kN with increase of filler content from 10wt% to 30wt%. On the contrary, the shear force of PSSTs with CaO and SiO₂ decline obviously from 2.1kN to 1.2kN, and 1.7kN to 0.6kN respectively. The wear rate of PSST depends on not only its own mechanical strength but also the dissolution rate of the filler. It comes out that the wear rate of PSST with Zn is similar to that of PSST with SiO₂, ranges from 0.04mm/h to 0.13mm/h. The wear rate of PSST with CaO is much lower, ranges from 0.02 mm/h to 0.08 mm/h.

Abstract: To improve the machining efficiency as well as surface roughness, a resin-bonded fixed abrasive tool is developed for lapping process of stainless steel substrate. To optimize the lapping ability of the fixed abrasive tool, the influences of bond material concentration on the mechanical properties of fixed abrasive lapping tool, including structure hardness, shear strength, the water-absorbing capacity and modulus of elasticity in compression are investigated. The micro structure of tools is also observed. Tools made of #1000 SiC abrasive and resin with different concentrations is employed in the tests. It is found, the hardness, shear strength, and modulus of elasticity in compression reach highest value, as the 35%wt bond material are used. The water-absorbing capacity increases as the bond material concentration decreases. It is judged from the SEM images that the number of pores in tool with 35%wt bond material is at the most.

Abstract: The dressing principle of a newly developed metal bonded superabrasive tool named porous self-generation superabrasive tool (PSST) is introduced. It is found that the ‘soluble’ filler added in the bond material can be dissolved by certain solution, and porous structure can be formed on the highly compacted surface layer of the metal-bonded superabrasive tool. The dressing process of PSST are investigated by a series of lapping experiments. Surface topography of PSST during lapping process is observed. It is found that the porous structure can be maintained on the PSST surface layer during the lapping process. There is little jam happened on the PSST surface. The generated porous binder on PSST surface layer is more susceptible to bond fracture, which is benefit to the self-sharpening of the metal bonded superabrasive tool.

Abstract: After making a detailed analysis about the one-side machining theory, based on the homogeneous coordinate transformation and the conjugate meshing theory of spatial mechanisms, applying Newton’s iteration, this paper realizes the synthetic analysis of the one-side milling profile error about the inner engaged globoidal cam for the potential cutter error and installation inaccuracy. A computer simulation example is presented, and the results can effectively disclosure and predict the law of influence of the various errors on the cam profile normal error. Consequently, a scientific proof has been supplied to improve the precision and quality of the one-side machining of the inner engaged globoidal cam.

Abstract: The lapping trace distribution on ball surface is one of the key factors during the lapping process, which can affect the sphericity of lapping. The Rotated Dual-Plates lapping mode (RDP lapping mode) can achieve better uniformity of lapping trace distribution on precision ball surface, which ensure the results of forming sphere by lapping. Combining with the basic principle of RDP lapping mode, as well as the analysis of the kinematics of the RDP lapping method, this paper puts forward a basic rule about the material removal at the contact point between the ball and the plate with the material removal rate equation of bearing steel, and the improvement of the sphericity which can be simulated, and is defined as the lapping uniformity according to basic rule equation. The influence caused by the lapping pressure and the speed of the plates are considered in the simulation, the surface of ball is triangle grid divided. The uniformity of lapping is evaluated at different speed ratio, and eventually a better curve of the speed ratio can be got, so the lapping uniformity during the RDP lapping mode can finally be accurately evaluated.

Abstract: Spin angle is an important target of expressing ball rotation in the lapping process. Whether lapping track can uniformly cover the ball surface or not is directly determined by the variation of the angle. The simulation of spin angle track of the ball based on ADAMS (Automatic Dynamic Analysis of Mechanical Systems) with Dual Rotation Plates Lapping Method by applying virtual prototype technology and using ADAMS is given by the article. The track based on ADAMS is similar with the track of using mathematical theory on the whole. The simulation results show that DRP lapping method owns better lapping uniformity and it is easy to apply to science for the simplicity of structure and control. The spherical lapping uniformity will be further studied with ADAMS in a convenient way.

Abstract: The V-groove angle of the machine is considered as one of important factors affecting the processing and the ball’s precision. To study its effect, the three-dimensional model of RDP lapping machine is built and a series of simulations at different V-groove angles are carried out, using the software ADAMS based on the RDP principle. The influence of three parameters including spin angle, spin angular velocity and revolution angular velocity are discussed by observing and analyzing the simulation results. It is concluded that some optimized V-groove angles can improve the sphericity of ball; some ones can induce the balls to move back and roll during some periods of the processing.