Qiu Sheng Yan

Influence of Magnetic Field Strength on Polishing Effect of the Tiny-Grinding Wheel Cluster Based on the Magnetorheological Effect

A new tiny-grinding wheel cluster polishing method based on the Magnetorheological (MR) effect is presented to polish optical glass in this paper and some process experiments were conducted to reveal the influence of magnetic field strength, the content of carbonyl iron in the MR fluid and the speed of polishing disc on the material removal rate and the surface roughness of the glass workpiece. The results indicate that when the external magnetic field is applied, the material removal rate of the workpiece improves rapidly but the surface roughness increases slightly. When the Magnetic field strength is 100 Gs and the content of carbonyl iron is 3.5%, the material removal rate improves by a factor of 16.8% compared with that of the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece increases unobviously.

Micro Machining of Three-Dimensional Microstructure with the Tiny-Grinding Wheel Based on the Electro-Magneto-Rheological Effect

Using the tiny-grinding wheel based on the synergistic effect of the electro-magneto- rheological (EMR) fluid, a novel method is presented to machine the three-dimensional (3D) microstructure of hard-brittle materials. Machining experiments of micro-groove were conducted to reveal the machining performances of the tiny-grinding wheel. Experimental results confirm the effectiveness and feasibility of the micro machining technique with the EMR effect-based tiny-grinding wheel. The shape of machined micro groove is found to be an inverted trapezoid, and the material removal mode of normal glass with the micro machining method is the plastic-removal mode. With the increase of the rotation speed of the tool, the material removal rate, width and depth of micro grooves increased first and decreased afterwards. The maximum removal rate, width and depth of micro groove occur at different speeds of the tool.

Influence of Dresser Setting and Assembling Errors on Shape Precision of Form Wheel

Influence of dresser setting highness error and assembling error on size precision and shape precision of dressed wheel section is studied and error emulational analyzing is carried out in NC dressing form wheel. Analyzing results indicate: influence of dresser setting highness error is quite small and can be ignored, influence of dresser radial or axial assembling error on shape precision of dressed wheel section is biggish and influence of axial assembling error is bigger among them, the latter can bring wheel section shape error of the same order as itself. Therefore, necessary measures must be taken to insure that assembling errors is smaller than 10 μm in dresser assembling, then requirement of form wheel dressing precision can be met.

Advanced Nano-Finishing Process of SrTiO3 Substrate by Cluster MR-Effect Plate

As a new multifunctional material, strontium titanate (SrTiO3) ceramic has a wide application in grain boundary layer capacitor (GBLC) with the microstructure characteristics of semi-conductive crystalline grain and insulated boundary. An ultra-precision nanofishing technique is developed to lap and polish the brittle and thin SrTiO3 substrate with the cluster MR-effect plate where the abrasives are constrained by the cluster MR-effect chains, under the influence of a magnetic field, the carbonyl iron particles (CIPs) and non-magnetic abrasive particles remove material from the surface of workpiece being machined in this paper. Mahr XT20 roughmeter, Keyence VHX-600 and Olympus S4000 microscopes are used to investigate the characteristic of machined surface and the mechanism of material removal. An ultra-smooth planarization surface of SrTiO3 substrate with surface roughness Ra 3.8 nm (Mahr), RMS 0.973 nm (Veeco interferometer) is obtained under a high efficiency. It is found that the pore structures of the sintered substrate would weak the machinability of SrTiO3 and influence the further improvement of surface quality.

Ultra Smooth Polishing Research Based on the Cluster Magnetorheological Effect

Based on the principle of MR polishing processing, cluster MR-effect polishing method which formed by cluster distributed magnetic body has been put forward in this article. The author analyzed the principle of the cluster MR-effect plane polishing, developed experimental device and conducted processing experiment to K9 optical glass and silicon slice. Results show that the method is feasible and can realize high precision polishing. The surface roughness of K9 glass and silicon slice can achieve respectively Ra0.005µm and Ra0.016µm finally after processed. It has high efficiency at the same time, the surface roughness can decrease 1 order of magnitude after processed 10 minutes, the surface roughness of K9 glass and silicon slice can realize respectively decrease 3 orders of magnitude and 1 order of magnitude after processed 50 minutes.

Ultra Smooth Planarization Polishing Technique Based on the Cluster Magnetorheological Effect

A new planarization polishing method based on the cluster magnetorheological (MR) effect is presented to polish optical glass in this paper. Some process experiments were conducted to reveal the influence of the content of carbonyl iron and the abrasive materials in the MR fluid on the machining effect, and the machining characteristic of polished surface was studied. The results indicate that the surface roughness of the polished workpiece can be reduced rapidly when the strong magnetic field is applied, and ultra smooth surface with Ra 1.4 nm can be achieved while the CeO2 abrasives are used in the MR fluid. The content of carbonyl iron obviously influences the machining effect of this planarization polishing method based on cluster MR-effect. With the increase of the content of carbonyl iron in the MR fluid, the material removal rate improves and the surface roughness reduces rapidly. However, the difference of abrasive material results in various machining effects. As for the K9 optical glass, the CeO2 abrasive is better polishing abrasive than the SiC abrasive in the planarization polishing technique based on the cluster MR-effect.

Development of a New Plate Polishing Technique with an Instantaneous Tiny-Grinding Wheel Cluster Based on Magnetorheological Effect

A new plate polishing technique with an instantaneous tiny-grinding wheel cluster based on the magnetorheological (MR) effect is presented in this paper, and some experiments were conducted to prove its effectiveness and applicability. Under certain experimental condition, the material removal rate was improved by a factor of 20.84% as compared with the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece was not obviously increased. Furthermore, the composite of the MR fluid was optimized to obtain the best polishing performance. On the basis of the experimental results, the material removal model of the new plate polishing technique was presented.

A Study of Micro Machining with Instantaneous Tiny-Grinding Wheel Based on the Fe3O4 Magnetorheological Fluid

In this study, Fe3O4 particles were used as magnetic particles to form Fe3O4 magnetorheological (MR) fluid, and experiments were conducted to polish optical glass using this Fe3O4 MR fluid. The machining characteristics of glass surface with different MR fluids that are added diamond abrasives and short fibres are studied. Experimental results indicate that the tiny-grinding wheel based on the Fe3O4 MR fluid can effectively polish optical glass and that the maximum diameter and depth of machined region increase obviously in the presence of diamond abrasives and short fibres. When both of diamond particles and short fibres are added to the Fe3O4 MR fluid, the removal efficiency of the tiny-grinding wheel is markedly enhanced due to the synergetic effect of diamond abrasives and fibres.

A Novel Superfine Machining Technology Based on the Magnetorheological Effect of Abrasive Slurry

Based on the magnetorheological (MR) effect of abrasive slurry, this paper presents an innovative superfine machining method. In this technique, the particle-dispersed MR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles so as to form a dynamical tiny-grinding wheel. This tiny-grinding wheel can be used to polish the surface of brittle materials in millimeter or sub-millimeter scale. The characteristics of the machined glass surfaces examined by the scanning electron microscope (SEM) and the Talysurf roughness tester confirmed the effectiveness of the finishing technique. The machined surface with convex center and concave fringe demonstrates that the material removal process is dominated by the synergy of the applied pressure and the relative velocity between the abrasives and workpiece. In the case of glass finishing, the mode of material removal is found to be plastic, and controlled by the abrasive-wear mechanism.

Error Estimate of Approximate Double Circular Arc Interpolated Method for Curve Smoothing

Approximate Double Circular Arc Interpolated Method which was put forward by author, is different from other circular arc interpolated methods in demanding only the corner between normal directions of each circular arcs at intersection point are less than designated allowed value but not demanding contiguous circular arcs are tangent, and makes the calculating be predigested. In order to estimate error of the method, emulated calculating is carried out, namely the course of curve being obtained by reverse engineering is simulated in this paper. The results show: if space between measure points is about 0.1mm in curve being obtained by reverse engineering, then, the most departure of smoothing results from original curve is 0.552μm for the stated example. Influence of the error on NC machining is quite small, so it can meet the needs of NC machining.