Study On The Precise Micro Fabrication Of Roller Grating Template

As a detection device of top grade CNC (Computer numerical control) machinetools for precise grating position detection, large scale micro-pitch grating directlydetermines the level of the national manufacturing capacity of CNC machine tools.And using nanoprinting roller technology to achieve ultra-high-precision large scalemicro-pitch grating is a viable technology innovation. In this paper, the micro-cuttingprocess of the V-shaped grooves on roller grating template for nanoimprint wasinvestigated. We also presented machining method by FIB milling for the diamondtool used in the micro-cutting process. We focused on the three main aspects ofmicro-cutting: the manufacturing method by FIB milling for the diamond tool, theoptimizing of the micro-cutting process of roller grating template and the mechanismto explore micro-characterization during the process.To improve the manufacturing method by FIB milling for the diamond tool, wedesigned and manufactured several kinds of sharp edge micro-tool in geometricshapes such as triangular, trapezoidal, etc. by this method we improved the surfacequality significantly. To fill the need of imprinting we also designed several kinds ofsingle crystal diamond tool in different geometric shape, which all achieved goodcarving effects;On the aspect of the micro-cutting process of roller grating template, based on thestudy of processing on different pitch (0.5μm~20μm cycle), we put up a theory abouthow to infer the impacts of micro-cutting process on the quality of micro-cutting,which is through the morphological changes of chips. Based on this theory, wederived variety ways to improve surface quality and reduce the burr. Two of them areincreasing the rake face angel and bringing in multi-step, these two steps have themost obvious effects on improving the quality of cutting surface. By lots ofexperiment with different pitches, we obtained the parameters which applicable at allpitch under the multi-step process. And we found that based on different depths of thefirst step of cutting, in the second step, the best cutting effects should be obtained with0.33to0.5times the first step cutting depth. We optimized design and manufacture ofthe cutting tools, and researched the20μm,10μm and4μm pitch precision micro cutting of a diameter of110mm roller grating template in full circle, by consideringvarious factors such as efficiency, quality of cutting, quality of nanoimprint, etc. in thecutting process of10μm pitch, the number of the grooves is more than ten thousand,the cutting time is over62hours, the average deviation is~10nm, and the total spliceerror of the roller grating template is less than500nm.On the aspects of the mechanism to explore micro-characterization during theprocess, we discovered a phenomenon through the experiments of different cuttingpitches in the micro-cutting process. When the pitch was reduced from20μm to10μm,under the same cutting parameters, the cutting quality will be significantly improved.However, from the decrease of10μm to2μm, the cutting quality was not obviouslyimproved during cutting process, and when the cutting cycle is less than2μm, thereeven appeared the phenomenon of continuous area with burrs. Based on thisphenomenon, we drew the conclusion that the main factor which affect the cuttingquality under small cutting cycle is the metallographic distribution of the brown brassthrough the EDS analysis and ion beam imaging microscopy characterizationmethods.