KDP晶体超精密飞切加工表面形貌形成过程仿真与实验研究
发布时间：2018-10-11 11:53
【摘要】：KDP晶体(KH2PO4)是惯性约束核聚变固体激光器光路系统中的关键光学元件,制造精度要求很高,但是KDP晶体具有易潮解、质软、脆性高、易开裂等不利于加工的特点,使其成为最难加工的光学元件。目前对KDP晶体的加工广泛使用的是超精密飞切加工技术。如何在加工中控制好KDP晶体的粗糙度和波纹度误差是当下研究的重点。本文首先分析了超精密飞切加工表面形貌形成过程仿真模型中需要考虑的影响因素,主要包括主轴的偏摆运动、刀具—工件的相对振动、切削过程刀具的热变形情况和切削参数。该加工表面形貌形成过程仿真模型的建立是基于加工的运动规律,加工表面形貌由刀具在工件上的切削运动轮廓形成。因此分别对各影响因素建立了刀尖的运动规律。其中,由于切削过程中刀具热膨胀导致的刀尖位移变化不能通过实验测量。因此本文进行了超精密飞切加工主切削力的测量实验,并建立了切削热理论模型,计算了切削过程中不同切削参数和主切削力对应的输入刀尖的热流量,通过有限元仿真的方法分析了刀具热变形所引起的刀尖位移变化,从而拟合得到了相应的刀尖位移方程。此外,本文还考虑了多次切削的切削截面轮廓干涉现象和刀尖圆弧半径对于仿真中切削深度的影响,在仿真算法中进行了相应的设计并建立了完整的超精密飞切加工表面形貌的仿真模型。利用所建立的KDP晶体超精密飞切加工表面形貌的仿真模型,本文分别分析了切削参数、主轴偏摆运动、刀具—工件的相对振动以及刀具的热变形对KDP晶体加工表面形貌的影响。分析过程中通过编程实现了对仿真形貌的滤波,形貌信息提取及粗糙度、波纹度误差的评价。结果表明切削参数对工件表面粗糙度的影响较大,而主轴偏摆运动及刀具—工件相对振动情况对粗糙度和波纹度均有影响,刀具的热变形不会对粗糙度和波纹度误差造成明显影响,其主要影响加工表面的面形特征。最后,进行了KDP晶体的超精密飞切加工实验,对实验结果进行了分析并验证了超精密飞切加工表面形貌形成过程仿真模型的有效性及合理性。利用本文中的KDP晶体超精密飞切加工表面形貌形成过程仿真模型可以分析不同加工条件下的加工表面形貌变化规律,优化加工过程参数,对于KDP晶体加工表面形貌精度的提高是很有意义的。
[Abstract]:KDP crystal (KH2PO4) is a key optical element in the optical system of inertial confinement fusion solid-state laser. The manufacturing precision is very high, but the KDP crystal has the characteristics of easy moisture solution, soft quality, high brittleness, easy cracking and so on. Make it the most difficult optical element to process. At present, ultra-precision flying cutting technology is widely used in the processing of KDP crystals. How to control the roughness and corrugation error of KDP crystal is the focus of current research. In this paper, the factors that need to be considered in the simulation model of the formation process of surface morphology in ultra-precision flying cutting are analyzed, including the deflection of the spindle, the relative vibration of the cutting tool and workpiece. Hot deformation of cutting tool and cutting parameters. The simulation model of the formation process of the machined surface topography is based on the motion law of the machining, and the machined surface morphology is formed by the cutting contour of the cutting tool on the workpiece. Therefore, the movement law of knife tip is established for each influencing factor. The change of tip displacement caused by cutting tool thermal expansion can not be measured experimentally. In this paper, the measurement experiment of the main cutting force of ultra-precision flying cutting is carried out, and the theoretical model of cutting heat is established, and the heat flux of the input cutter tip corresponding to different cutting parameters and main cutting forces in the cutting process is calculated. The change of tip displacement caused by tool thermal deformation is analyzed by finite element simulation method, and the corresponding tip displacement equation is obtained by fitting. In addition, the influence of the interference phenomenon of cutting cross-section profile and the radius of cutter tip arc on the cutting depth in the simulation is also considered in this paper. The simulation algorithm is designed and a complete simulation model of the surface morphology of ultra-precision flying cutting is established. Based on the simulation model of the surface morphology of ultra-precision flying cutting of KDP crystal, the effects of cutting parameters, the movement of spindle deflection, the relative vibration of cutter and workpiece and the thermal deformation of tool on the surface morphology of KDP crystal are analyzed in this paper. In the process of analysis, the filter of simulation topography, the extraction of topography information and the evaluation of roughness and corrugation error are realized by programming. The results show that the cutting parameters have a great influence on the surface roughness of the workpiece, while the movement of the spindle deflection and the relative vibration of the cutting tool and workpiece have effects on the roughness and the corrugation of the workpiece. The thermal deformation of the tool has no obvious effect on roughness and corrugation error, and it mainly affects the surface shape characteristics of the machined surface. Finally, the experiment of ultra-precision flying cutting of KDP crystal is carried out. The experimental results are analyzed and the validity and rationality of the simulation model for the formation process of surface morphology of ultra-precision flying cutting are verified. The simulation model of the formation process of the surface morphology in ultra-precision flight cutting of KDP crystal in this paper can be used to analyze the changing law of the surface morphology under different processing conditions and to optimize the processing process parameters. It is significant to improve the surface morphology precision of KDP crystal.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TL632;TN248.1
本文编号：2264090
[Abstract]:KDP crystal (KH2PO4) is a key optical element in the optical system of inertial confinement fusion solid-state laser. The manufacturing precision is very high, but the KDP crystal has the characteristics of easy moisture solution, soft quality, high brittleness, easy cracking and so on. Make it the most difficult optical element to process. At present, ultra-precision flying cutting technology is widely used in the processing of KDP crystals. How to control the roughness and corrugation error of KDP crystal is the focus of current research. In this paper, the factors that need to be considered in the simulation model of the formation process of surface morphology in ultra-precision flying cutting are analyzed, including the deflection of the spindle, the relative vibration of the cutting tool and workpiece. Hot deformation of cutting tool and cutting parameters. The simulation model of the formation process of the machined surface topography is based on the motion law of the machining, and the machined surface morphology is formed by the cutting contour of the cutting tool on the workpiece. Therefore, the movement law of knife tip is established for each influencing factor. The change of tip displacement caused by cutting tool thermal expansion can not be measured experimentally. In this paper, the measurement experiment of the main cutting force of ultra-precision flying cutting is carried out, and the theoretical model of cutting heat is established, and the heat flux of the input cutter tip corresponding to different cutting parameters and main cutting forces in the cutting process is calculated. The change of tip displacement caused by tool thermal deformation is analyzed by finite element simulation method, and the corresponding tip displacement equation is obtained by fitting. In addition, the influence of the interference phenomenon of cutting cross-section profile and the radius of cutter tip arc on the cutting depth in the simulation is also considered in this paper. The simulation algorithm is designed and a complete simulation model of the surface morphology of ultra-precision flying cutting is established. Based on the simulation model of the surface morphology of ultra-precision flying cutting of KDP crystal, the effects of cutting parameters, the movement of spindle deflection, the relative vibration of cutter and workpiece and the thermal deformation of tool on the surface morphology of KDP crystal are analyzed in this paper. In the process of analysis, the filter of simulation topography, the extraction of topography information and the evaluation of roughness and corrugation error are realized by programming. The results show that the cutting parameters have a great influence on the surface roughness of the workpiece, while the movement of the spindle deflection and the relative vibration of the cutting tool and workpiece have effects on the roughness and the corrugation of the workpiece. The thermal deformation of the tool has no obvious effect on roughness and corrugation error, and it mainly affects the surface shape characteristics of the machined surface. Finally, the experiment of ultra-precision flying cutting of KDP crystal is carried out. The experimental results are analyzed and the validity and rationality of the simulation model for the formation process of surface morphology of ultra-precision flying cutting are verified. The simulation model of the formation process of the surface morphology in ultra-precision flight cutting of KDP crystal in this paper can be used to analyze the changing law of the surface morphology under different processing conditions and to optimize the processing process parameters. It is significant to improve the surface morphology precision of KDP crystal.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TL632;TN248.1
【参考文献】
相关期刊论文 前2条
1 谢英明;李新政;郑滨;杨兰兰;;KDP(KH_2PO_4)晶体材料的研究进展[J];河北工业科技;2006年06期
2 王皖燕;晶体学和晶体材料研究的进展[J];科技导报;2002年03期
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