Research On Machining Method Of Hexagonal Cube Corner Array Retroreflector

Retroreflectors are common optical element that returns incident light in a certain angular range parallel or approximately parallel to the direction of incidence to the light source.Through decades of research and development,retroreflectors have evolved into higher-performance and more versatile cell array structures.These arrays typically consist of a single angular cone prism structure in polygonal shapes such as hexagons and triangles.Among them,the hexagonal cube corner reflector,by its unique optical reflection characteristics,and its simple reflection mechanism,high reflectivity.Retroreflectors are widely used,such as road safety warning device,helmet display system,optical measurement system,suspension display,etc.With the continuous development of modern industrial technology,the current requirements for optical performance,production efficiency,and production cost of hexagonal cube corner reflectors are increasing.However,the traditional processing method for hexagonal cube corner array structure,Pin-Bundling-Electroform（PBE）,gradually becomes difficult to meet the current usage requirements.Therefore a new processing method for hexagonal cube corner return reflector needs to be proposed to meet the current optical performance as well as processing efficiency requirements.The thesis developed a new machining method for hexagonal cube corner arrays with higher efficiency and wider applicability,and analyzes and investigates the cutting mechanism of the method,and finally performs experimental verification of the machining on an ultra-precision machine tool.This thesis focuses on the following four parts of the research work.（1）A staggered cutting machining method for hexagonal cube corner arrays was proposed.The cutting strategy of the method was analyzed to improve the machining efficiency.In order to realize the machining of hexagonal cube corner arrays,the horizontal direction machining scheme used a specific angle inclined table fixture and the vertical direction machining scheme used the machine tool turntable rotation are studied respectively.Special wedge-shaped diamond tools were designed for the characteristics of this cutting and machining method to realize the cutting and machining of cube corner microstructures.（2）The method of generating machining paths for hexagonal cube corner arrays was studied and the machining time was estimated.Combining the cube corner structure and the geometric characteristics of the diamond tool,the corresponding machining programs were calculated and generated for different processes in the cutting process.The machining time of the staggered cutting method was estimated,and the results showed that the proposed method had higher machining efficiency.（3）The cutting mechanism of the diamond dislocating cutting method was analyzed,and the cutting force variation law at different cutting depths in each machining stage of the cutting process was studied.The finite element models of different machining stages were established using ABAQUS finite element analysis software to analyze and calculate the magnitude of cutting forces at each stage,which provides theoretical guidance for the optimization of subsequent machining experimental process parameters.（4）Experimental studies on the machining of hexagonal cube corner arrays were carried out,and the machining results were analyzed.The cutting force measurement experiment,vertical machining experiment,and horizontal machining experiment were carried out on a5-axis ultra-precision machine（Moore Nanotech 350FG）.The actual cutting forces at different stages of the machining process were measured to verify the correctness of the preliminary cutting force simulation;the hexagonal cube corner array structures with 200 m and 500 m structural unit sizes were successfully machined by the vertical and horizontal machining schemes,respectively.Finally,the roughness measurement of the optical reflective surface of the array structure basically meets the requirements of the optical performance of the reflector array,which verifies the feasibility of the diamond dislocating cutting method.