| As the rapid economic and social development promote the further development of military astronomy, especially, the improvement of various fields of aeronautics and astronautics, it owns extraordinary significance for any country. All kinds of space mirrors are widely used in many aspects including large space telescope, a variety of satellites, laser radar system, space telescope and high resolution camera. Gradually, traditional materials can’t meet the demand for new mirror. Silicon carbide materials, favored by many countries, becomes the first choice for preparing space mirrors, due to a series of excellent physical and chemical properties, such as high elastic modulus, mechanical properties of isotropic.Currently, the small head grinding machining methods own low efficiency and high manufacturing cost as well as small batch and single production of silicon carbide mirror. Abrasive belt grinding, an efficient processing way, can obtain good machined surface easily. Combined with abrasive belt grinding and multi-point forming technology, new shape tool system has been developed in this paper, which can both adapt to all kinds of machining surface and improve the efficiency of processing. At the same time, this new type tool system can be adjusted to form a variety of surface type press plate. It removes mold design and manufacturing sectors, which greatly reduces the cost and the production cycle.The new type tool system includes grinding and polishing mechanism, the tensioning mechanism and electrolytic mechanism. The grinding and polishing mechanism by means of multi-point forming technology use two-dimensional mobile platform and vertical motors to control rotation of the screw. 100 contact heads could be drove to move up and down independently, which can be adjusted to the press plate with a variety of free surface. Considering the simple, fast, efficient belt tensioning, pneumatic cylinder is used to drive belt tensioner pulley. Wrap angle of the rubber-coated drive wheel is greater than 200°, which can prevent skidding effectively. Three-dimensional solid modeling of the new type tool system has been established to get virtual assembly and interference checking by CATIA V5. Besides, engineering drawings of the components have been drew and the tool system has been processed and assembled.This new type tool system has parallel and serial adjustment ways. By contrast, parallel adjustment has been chosen by this new type tool system to satisfy the demand for the size and frequency. Analyze the adjustment time and error to choose reasonable motor. Adjustment simulation of new type tool system has been established by CATIA DMU in the paper. According to the existing free-form surfaces, three-dimensional surface model has been created and specific plane has been selected to set point cloud. The point cloud could be projected onto the curved surface along the Z axis to acquire free form surface composed of point cloud. Then the coordinates of point cloud on the free surface would be extracted and drawn into the electronic prototype to complete the adjustment simulation.Due to multitude of abrasive particles own different grit shape and grinding depth in the belt grinding, it is difficult to achieve analysis of the overall grinding process. On the contrary, single abrasive grinding behavior seems to be got easily by finite element simulation. A series of single abrasive grinding finite element models have been established to analyze the effect of grinding process caused by different grinding depth, speed and the parameters of abrasive, which has response by tangential force, normal force, equivalent stress and equivalent plastic strain. Furthermore, in order to verify the simulation and study on the mechanism of abrasive belt grinding, scratch test and abrasive belt grinding forming experiment have been conducted to measure material removal rate and surface roughness. |
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