Evaluation Method For Service Life Of Micro-arc Diamond Tool

Ultra-precision machining refers to technologies that enable the machining of surfaces with nanometer-level surface roughness and sub-micron geometric shape accuracy.The cutting process with single crystal diamond tools,often referred to as single point diamond machining,is an important way to achieve ultra-precision machining,and its initial development was focused on optical machining for energy and defense-related needs.Today,single point diamond machining has a wider range of applications,including precision optical freeform fabrication for defense and commercial applications,as well as for functional surfaces.Micro-arc diamond tools are circular-edge diamond tools with tip radii less than 100 ?m that can be used to machine optical and microstructured surfaces.Machining optical surfaces with them can reduce diffraction effects.Microstructured surfaces are a way to realize functional surfaces and are often used in backlight panels in LCDs to make the picture clearer by the principle of optical scattering.A sinusoidal microstructure is a surface structure with a wavelength of 10 ?m and an amplitude of 5 ?m.The smaller the wavelength and the larger the amplitude,the smaller the radius of the tool tip arc that needs to be used.Since the tool tip arc radius is very small,tool wear is easily generated during machining,which leads to poor surface quality of the machined workpiece and failure to meet production requirements.Tool life is mainly related to tool wear,when the tool wears to a certain extent,the surface quality of the machined workpiece does not meet the production requirements,the tool will fail.In the production practice,to know the tool life in advance,can guide the producer when to change the tool,improve production efficiency.This paper focuses on a systematic study of the service life of micro-arc diamond tools,which includes the following aspects.Firstly,the wear form and wear mechanism of micro-arc diamond tools cutting 6061 aluminum alloy are studied.Several high-quality micro-arc diamond tools were prepared on a PG3 B planetary diamond tool grinding machine,and the prepared tools were used to cut 6061 aluminum alloy on an ultra-precision four-axis machine tool developed by HIT for experiments,which caused a certain degree of tool wear.The surface morphology of the tool was observed by scanning electron microscope,and it was found that the tool wear was mainly in the form of rear tool surface wear.X-ray energy spectrum analysis of the tool wear area showed that no diffuse wear occurred.The diamond structure was examined using a pinpoint-enhanced laser confocal Raman spectroscopy system,and no phase change from diamond to graphite was found;under the experimental conditions of this paper,the wear mechanism of the tool cutting 6061 aluminum alloy is mainly chemical wear,and mechanical wear also exists.Secondly,the evaluation index of the service life of micro-arc diamond tools cutting 6061 aluminum alloy was determined.The prepared tools were used to turn the end face of 6061 aluminum alloy workpiece on an ultra-precision four-axis machine tool,and the workpiece face roughness Sa and tool surface ripple degree Wa were measured at each turning distance.A wear model was established,and the width of the wear zone and the wear volume were derived from the tool tip surface corrugation.The relationship between cutting distance,micro-arc diamond tool tip circular corrugation,workpiece surface roughness,and micro-arc tool wear(wear band width and wear volume)was obtained,and the tool life evaluation index was determined in a multi-dimensional way.Finally,the service life of micro-arc diamond tools was evaluated based on cutting dosage and tool geometry parameters.Based on the cutting dosage,a three-factor,three-level orthogonal test was established to obtain the tool life equation.Based on this equation,the tool life can be predicted and the effect of cutting dosage on the service life is obtained.Based on the geometric parameters of the tool,the influence law of the front and back angles of the tool on the tool life was obtained.