Measurement And Error Evaluation Of Microstructure Arrays In Ultra-precision Machining Process

The ultra-precision lathe(UPL)based on ditamond cutting is a device with high positioning accuracy.Also with the multiple degrees of freedom,the UPL is widely used in different fields,such as semiconductor manufacturing,aeronautics and astronautics.Although the lathe always works in a high positioning accuracy state,errors could be introduced by the tool wear during long time continuous machining and other environment conditions.So high-precision measurement of the cut surface is needed to make some error compensation,which is important for the machining of large-area of microstructure arrays.Most of the existing high-precision measurement systems work in a customized measuring space,and to take an offine measurement would introduce errors from the secondary installation and hinders the efficiency of the machining process.In this paper,an on-machine measurement system was developed for the topography during UPL based diamond cutting.Meanwhile,a surface matching algorithm based on the weighted evaluation of Gaussian curvature is proposed,and the error evaluation process for the topography measurement surface and designed surface is prepared.Then two on-machine measurement experiments of artificial compound eye components with plane and spherical substrate were carried out,respectively.The error evaluation of plane compound eyes array shows the whole process about machining and testing with the on-machine measurement system.This paper presents the development of an on-machine measurement system for micro-structure array in UPL-based diamond cutting.The measuring system utilized the idea of scanning probe microscope,and a centering scheme for measurement system is proposed;With the extraction algorihm of feature points on freeform surface by Gaussian curvature features,the system makes a quick matching process with the extraction points between the measured surface and the designed surface;The on-machine measurement experiments with compound eye array on plane substrate and the spherical one,were conducted respectively.Then the matching and error evaluation of the plane compound eyes array are present to verify the matching algorithm proposed,and the matching error maps helps to make an evaluation of machining process.The development of the on-machine measurement system and the machining algorithm with Gaussian curvature features help to build up the"Design-Process-Measurement" cycle,and contribute to the development of the ultra-precision processing of microstructure array.