| The finishing of mold manufacturing is to modify the dimension precision and surface quality of the workpiece, which approximately consumes 40-50% of the whole manufacturing time. For the application of laser hardening technology in the mold field, the finishing of the pneumatic grinding wheel with softness consolidation abrasives can solve difficult problems of high hardness, high wear resistance and complex free-form surface of the laser strengthening mold surface. In the absence of research on the surface morphology and finishing on surface, there is not an effective model for surface processing and simulation analysis. Initial finishing experimental results show that softness consolidation abrasives wear severely, and abrasive particles fall off faster than the binder, which greatly reduces the wear particle effective processing participation rate and affects the finishing efficiency and processing quality.To realize the automatic precision finishing on the laser surface strengthening mold, this paper will research and construct pneumatic wheel surface topography model and initial finishing processing model based on the existing researches, which can simulate real surface manufacturing. It will optimize and improve the structure of the pneumatic wheel, which can increase the finishing efficiency and level up the processing quality. This paper mainly from the following aspects:(1) Aiming at constructing the contact surface morphology of the pneumatic wheel, contact behavior characteristics between grinding grains and workpiece are studied for reconstructing the non-Gaussian surface topography model of softness consolidation abrasives by using random field. For the simulation of finishing on workpiece surfaces, it needs to generate the wheel surface morphology by the given experiment parameter.(2) To solve problems of surface wear and abrasives fall-off, improved the traditional pneumatic wheel will be improved for avoiding changing and relocating the wheel head. The design of the layer-by-layer falling and exposure of abrasives of different sizes can save time and raise the finishing precision.(3) Based on layered elastic systems, multiple layers of the improved wheel was constructed and used in a dynamic simulation to analyze the influences of air pressure and rotational speed upon stress distribution for supporting the theoretical and data support for manufacturing and application of this modified pneumatic grinding wheel. An air pressure of 0~0.1MPa and rotational speed 1500 rpm should be used in practical applications.(4) Based on a projection relationship exists between abrasives on a pneumatic grinding wheel and the workpiece surface, the trajectory of single abrasive particle is be mapped. An algorithm is proposed to describe the interaction of SCA with the laser strengthened surface by introducing constraints of hardness, material removal model and material removal conditions.(5) According to the processing target, the corresponding experimental scheme is designed, and the experimental platform is set up for finishing of laser strengthened surfaces using pneumatic grinding wheels with softness consolidation abrasives. By finishing experiments of the material removal and surface quality, the correctness of models of pneumatic grinding wheel topography and finishing process is verified. The effectiveness of finishing on the laser surface strengthening mold by the pneumatic grinding wheels with softness consolidation abrasives is demonstrated by finishing experiments. The optimized pneumatic grinding wheel cannot improve the problem of abrasives fall-off, but also make finishing smoothly. The efficiency of finishing done by the progressive pneumatic grinding wheel was 34.6% higher than the efficiency of finishing done by the pneumatic grinding wheel with a single layer SCA. |
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