Research On Design Method And Material Removal Characteristic Of Softness Consolidation Abrasives Pneumatic Wheel

In mould industry, laser hardening could not only significantly improve surface hardness, wearing resistance and corrosion resistance, but also optimize performance of mould and extend its service life. However, these advantages have also brought tremendous difficulties to the finishing process of laser hardening surface, such as irregular freeform surface, high hardness and local difference of hardness. In the view of its wide future prospects, it becomes very important to figure out this problem.In allusion to the problems above, a new finishing method based on the softness consolidation abrasives (SCA) pneumatic wheel is brought forward in this paper. Firstly, in order to improve the tearing stability of interior rubber of SCA, fiber reinforced method is adopted. Meanwhile, the prediction models of modulus and ruggedness are established. Secondly the mechanics characteristic of hemispheric compound rubber is analysed by the simulation. Thirdly discrete element method is brought in for the research on the dynamic characteristic of SCA. Also moulding process of wheel is introduced. Finally the material removal prediction model of SCA is given, which is verified by the experiments. The main contents in this paper are as followed.(1) The distribution of the fiber in the compound rubber shows a complex poly-dimensional net. Orientation factor is used to normalize the fiber reinforce characteristic. The prediction model of modulus is set up by the modified Halpin-Tsai equation. At the same time, the prediction model of ruggedness is given. The test that Aramid Pulp is added to the Styrene-Butadiene rubber is finished and the hemispheric compound rubbers are created with kinds of size and different fiber volume fraction. The tensile tests’results are in accordance with the prediction model which is proved to be more accurate in the cases of using lower modulus of original rubber and improvement of fiber volume fraction. The points discussed above lay the foundations for the succedent performance analysis of pneumatic wheel.(2) The contact process between pneumatic wheel and workpiece is simulated and the conclusions show the stress increases with the improvement of fiber volume fraction and modulus of original rubber. On the contrary, the strain decreases in that case. Combined with the layers’ elastic theory, the dynamic characteristic of the pneumatic wheel is analysed and the relationship between stress and stain is given. The simulation shows that thin layer of compound rubber is beneficial to enhance the softness of the wheel and fit for the machining to surface with large curvature. However, the thick layer of compound rubber can help to concentrate the cutting stress and improve the efficiency of the machining. The analysis of mechanics characteristic of pneumatic in this section provides a basis for the optimization of the manufacturing parameters.(3) According to the soft-ball model of discrete element method, the normal and tangential contact stress formula has been established for the relationship discussion between two particles. The translational and rotational displacement formulas of SCA are given and the creeping phenomenon is proved out by the simulation. It is also verified that the SCA has much more powerful stress net and can supply more cutting stress working on the workpiece than the free abrasives’. Besides, the craft and evaluation criterion of manufacture of SCA has been introduced and the standard of mixture ratio between abrasives and binder is given for adapting to the different machining situation. The discussions above explain the microscopic mechanism of the SCA, which provides the basis for the material removal model in the next section.(4) The mechanics model of single particle is analysed and the relationship between microscopic mechanism of the SCA and macroscopic machining charateristic of the pneumatic wheel has been given. Combined with the Rabinoweizc’s theory, the coefficient of Preston equation is established. Meantime, cutting stress is modified in the case of particles’ working under the soft support and velocity formula of SCA is figured out. Finally, the material removal model of pneumatic wheel is given, which has been proved out by the experiments. The experimental results show that the SCA has better material removal ability than the free abrasives’and can avoid the scratches to the freeform surface which the fixed abrasives always left in the same situation. This section finally shows the SCA’s machining ability.