Study On Quality Control Technology Of Ultra Precision Manufacturing Process Of Optical Component Surfaces

With the development of the optical field,the manufacturing precision of the surface of the optical component of the optical system is getting higher and higher,and higher requirements are put forward for the processing precision of the optical manufacturing.The country’s increasing demand for ultra precision optical components in the fields of laser systems,astronomical observations,and lithography and projection has driven the development of ultra precision manufacturing technology.Ultra precision manufacturing has become the most important part of mechanical manufacturing.It not only directly affects the surface of component quality,but also affects the development of ultra precision manufacturing technology and the defense industry.The traditional polishing methods for processing optical components will introduce impurities to cause problems surface contamination,and sub-surface damage of the components and other problems,which severely restricts the improvement of the accuracy of modern optical systems.Ion beam figuring uses the sputtering effect of ions and surface atoms to achieve precise removal of the surface material of the component.The non-contact ion beam figuring avoids the above problems,and the removal function has a rotating Gaussian shape,high certainty,and good robustness.Compared with the traditional polishing methods,it is more suitable for the manufacture of high-precision optical components.This paper focuses on the two key issues of ion beam figuring surface thermal effect and ion beam figuring error analysis and control in the ultra precision manufacturing of optical component surfaces.The research work of the paper mainly includes the following parts:1)Modeling and stability analysis of the removal function of ion beam polishing.Based on the Sigmund material sputtering theory,a mathematical model of the removal function is established;the ion source is a key component of ion beam figuring.Three common ion sources are introduced.The experiment verifies the stability and analysis of the ion source by scanning the Faraday cup with the ion beam.The removal function is obtained by the line scanning polishing method of the ion beam on the element,and the stability of the removal function is verified by multiple sets of experiments under the same process parameters.Use SRIM software to simulate and analyze the influence of ion beam incident energy and incident angle on the removal function.2)Simulation of temperature field and thermal stress of ion beam processing optical components and optimization of processing technology.During the ion beam polishing process,due to the uneven heating of the surface of the component,thermal stress will be generated on the surface of the component,and the surface is prone to cracking due to the thermal stress.The energy deposition model of ion beam figuring is established and SRIM is used to simulate the heat conversion of incident ions,combined with Faraday cup scanning to obtain the current density of the ion beam,and then the heat source model of the ion beam on the surface of the component is established.Based on the simulation analysis of the distribution of temperature field and thermal stress field on the quartz surface under the action of the ion beam by ANSYS software,the process parameters are studied to reduce the influence of the ion beam on the thermal effect of the fused silica surface to ensure the ion beam processing of high precision optical components.3)Analysis and control of the surface error of optical components in ion beam figuring.The main sources of errors by ion beam figuring are analyzed,and the detection methods of surface shape errors of commonly used ion beam polishing optical components and the evaluation of the surface quality of the components are introduced.Different stacking spacing will cause different removal effects,and determining the optimal stacking spacing can not only ensure processing efficiency,but also obtain high-precision component surface accuracy.In addition,analyze and eliminate the edge effect existing in processing.After the correction,the ion beam figuring experiment was performed on the fused silica component with a diameter of 50 mm,and the convergence rate of the surface accuracy of the optical component reached to 5.75,and finally a high-precision component surface was obtained.