Simulation And Experimental Study On The Formation Of Burr In Micro Milling Of Metallic Glass

Metallic glass is also called amorphous alloy,and its inner atoms are arranged into microscopic disorder,which makes its interior without crystal defects such as grain boundaries and dislocations,so it can have high strength and has been used in national defense and military affairs.The fabrication of metal glass micro parts is supported by micro cutting technology.It is necessary to study the micro cutting process and surface quality,especially in micro milling.It is helpful to study the influencing factors of microburr and its influence law to promote the engineering application of metallic glass.In order to solve the problem of no accurate constitutive model of metal flow stress in existing finite element software,a model considering the influence of hydrostatic stress was established.According to the thermo-dynamic characteristics of metallic glass,the constitutive model equation is segmented by glass transition temperature creatively.The material constants in the model are solved by compression test and orthogonal cutting experiment.The two-dimensional cutting model is established by using the finite element software AdvantEdge.The accuracy of the model considering the influence of hydrostatic stress was tested by comparing the cutting force and chip shape of the simulation and experiment under the same parameters.On the basis of the constitutive model,the finite element models of 0.1mm diameter double-edged flat end micro tool and single-edged ball end micro tool are established.The types of micro-grooving burrs in flat end tool milling are found as follows: up milling top burr,down milling top burr,entrance side burr,exit side burr,ball end tool micro-groove milling burr type: entrance burr and exit burr The process of burr formation at various positions during microgroove milling is analyzed.In order to analyze the effect of cutting parameters and cutter geometric parameters on the formation of micro-groove milling burr,finite element simulation is carried out for micro-groove milling process under various parameters.The influence of parameters on burr size and burr morphology is analyzed quantitatively.A special burr in milling: bottom burr.The research shows that axial depth has the greatest influence on the size of burr in each position,and the ball end tool can effectively suppress the formation of top burr.However,burrs can be formed at the bottom of the groove and at the entrance and exit of the groove.By optimizing the cutting parameters and the geometric parameters of the tool,the burr size can be reduced.The research in this paper can provide a reference for the micro-milling of metal glass and the design of the micro-tool.