To Explore The Gridinding Mechanism Of KDP Crystal By Diamond Micro Structure

KDP(Potasstium Dihydrogen Phosphate,chemical formula of K2HP04)crystal has some characteristics,such as:high laser damage threshold,low optical absorption coefficient,high optical uniformity and good through the band,etc.At present,it is mainly used in electric shutter,electro-optic modulation,solid-state light,especially the large diameter of KDP crystals which is indispensable optical element to manufacture large laser system.Because of its processing characteristics(soft and fragile?easy deliquescence?sensitive to temperature changes?anisotropic and so on),it is now recognized as one of the difficult processing of optical materials.The conventional processing method of KDP crystal include cutting?single point diamond cutting?grinding?polishing?etc.Currently,there are some characteristics with the single point diamond cutting,diamond grinding wheel grinding and the magnetic rheological polishing which is belong to Ultra-precision machining way,such as small size waviness,grinding grain embedded,edge collapse and low efficiency.Aiming at the existing defects of traditional processing methods,this paper creatively puts forward the CVD diamond whole grain surface micro blade to processing the KDP crystal,and trying to find processing method to ensure machining efficiency under the premise of no small waviness and no grinding grain embedded,the specific research contents are as follows:(1)Design a diamond tool for the method,analyze the structure of CVD diamond machining surface micro blade and the processing parameters which influences the structure of the blade.The results show that:the micro blade distributed evenly and sharp;with pulse frequency changes,the density of micro blade distribution is different;(2)The feasibility study of this method.Analyze the movement of the machining process,explore the influence of the micro blade structure on surface roughness.And the results show that:The method is feasible,and the structure of the micro blade is the main factor which influences the surface roughness of crystal;(3)Comparing the microtopography and impurities embedded type of the crystals which processed by CVD diamond blade grinding and Diamond grinding wheel,results present that:Using the method of CVD diamond micro blade,the microtopography of crystal is uniform,and there is no micro broken area?no grain embedded,but embedded abrasive appears at local area;(4)Analyze the mechanical properties of the machined surface of KDP crystal.By studying indentation morphology under different load or different crystal orientation,we draw the conclusion that:KDP crystal has ductility domain;there exist obvious indentation size effect on crystal surface;both the maximum hardness and the minimum of fracture toughness appear at 50°of crystal orientation?...