光学玻璃F-theta自由曲面磨削的形状误差补偿精密加工研究

发布时间：2018-01-24 01:08

本文关键词： 光学自由曲面零件金刚石砂轮 F-theta透镜误差补偿精密磨削　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：与光学球形及非球面部件相比,光学自由曲面零件更能集成光学系统。因集成光学系统的聚热产生较高的温度,所以要采用耐高温、耐腐蚀、热变形小的光学玻璃作材料。但是,光学玻璃为硬脆性材料,机械加工易产生微裂纹,导致加工精度受损。金刚石砂轮因其优异的切削性能和良好的耐磨性,已经应用于光学轴对称非球面零件的精密磨削加工,但由于难于生成刀具轨迹而尚未应用于非轴对称的光学自由曲面零件加工。因此,提出采用椭圆环面金刚石砂轮,在三轴数控磨削中控制砂轮和工件的曲面相切点,实现光学玻璃自由曲面精密磨削加工。针对磨削中的砂轮、机械、设计等综合误差,提出形状误差补偿的精密磨削加工方法。首先,光学自由曲面零件设计为企业所需的激光打印机中F-theta透镜零件,然后,对椭圆环面砂轮的精密修整工艺参数进行正交试验研究。最后,建立自由曲面数控磨削的刀具轨迹法向算法,分析砂轮轮廓误差补偿、垂直误差补偿、法向误差补偿和磨削加工工艺参数对形状精度和表面质量的影响。具体研究结果如下:1、参照现有光学系统对激光打印机中F-theta透镜进行初始结构设计,并使用ZEMAX光学软件优化其结构以满足设计要求。2、影响砂轮修整形状误差的主要工艺参数为砂轮转速,较厚的磨石能提高砂轮修整精度;在合适的修整工艺条件下,砂轮轮廓形状误差可达到22.6μm。3、在F-theta透镜的误差补偿磨削加工中,砂轮轮廓误差补偿不需检测后的二次加工就可以减小形状误差55%。此外,垂直误差补偿和法向误差补偿分别可减小形状误差62%和64%。4、影响光学玻璃表面粗糙度的主要工艺参数为进给速度;在合适的轴向磨削工艺条件下能加工出粗糙度达44.7 nm的镜面光学自由曲面,从而避免了对零件的研磨抛光。综合上述,采用椭圆环面金刚石砂轮和刀具轨迹的法向算法,可以实现F-theta透镜的磨削加工。利用砂轮轮廓误差和工件曲面误差可以实现高精度的误差补偿加工。此外,采用#3000超细金刚石砂轮可以实现光学自由曲面零件的镜面磨削加工。
[Abstract]:Compared with optical spherical and aspherical components, optical free-form surface parts can integrate optical systems more effectively. Due to the high temperature due to the heat accumulation of integrated optical systems, high temperature and corrosion resistance should be adopted. Optical glass with small thermal deformation is used as material. However, optical glass is a hard brittle material, which is easy to produce micro-cracks in mechanical machining, which results in damage of machining accuracy. Diamond grinding wheel has excellent cutting performance and good wear resistance. It has been applied to the precision grinding of optical axisymmetric aspheric parts, but it has not been applied to the non-axisymmetric optical free-form surface parts because it is difficult to generate tool paths. The elliptical ring diamond grinding wheel is used to control the tangent point between the grinding wheel and the workpiece in the three-axis NC grinding to realize the precision grinding of the optical glass free surface. A precision grinding method for shape error compensation is proposed. Firstly, the optical free-form surface parts are designed for the F-theta lens parts in laser printers required by the enterprise. The orthogonal experimental study on the precision dressing process parameters of elliptical toroidal grinding wheel is carried out. Finally, the normal algorithm of tool path of NC grinding with free surface is established, and the contour error compensation and vertical error compensation of grinding wheel are analyzed. The effect of normal error compensation and grinding process parameters on shape accuracy and surface quality. The results are as follows: 1. According to the existing optical system, the initial structure of F-theta lens in laser printer is designed, and the structure of F-theta lens in laser printer is optimized by ZEMAX optical software to meet the design requirements. 2. The main technological parameter affecting the shape error of grinding wheel is wheel speed, and the thicker grinding stone can improve the dressing accuracy of grinding wheel. The profile error of grinding wheel can reach 22.6 渭 m.3 under proper dressing conditions, which is used in the error compensation grinding of F-theta lens. The contour error compensation of the grinding wheel can reduce the shape error by 55. In addition, the vertical error compensation and the normal error compensation can reduce the shape error by 62% and 64.4, respectively. The main technological parameters affecting the surface roughness of optical glass are feed speed. A mirror optical free surface with a roughness of 44.7 nm can be machined under suitable axial grinding conditions, thus avoiding the grinding and polishing of the parts. The normal algorithm of elliptical toroidal diamond grinding wheel and tool path is used. The grinding process of F-theta lens can be realized. The grinding wheel contour error and workpiece surface error can be used to compensate for the high accuracy. The mirror grinding of optical free-form surface parts can be realized by using #3000 ultrafine diamond grinding wheel.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ171.734

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