Research On Cutting Force And Cutting Thermal Characteristics During Gun Drilling Of Nickel-based Alloys

Superalloy material is an important part of the rapid development of aerospace engine.It is mainly used in combustion chamber,guide vane,turbine blade and other parts,accounting for 40% ?60% of the whole engine.Nickel base superalloy is the most critical structural material to promote the development of aeroengine.Due to its poor machinability and thermal conductivity,the machining tools need to be changed frequently when machining highprecision deep hole nickel base parts.In this paper,aiming at the difficult machining problem of nickel base superalloy,the machining characteristics of nickel base alloy are studied,mainly including the following aspects:Firstly,based on the machining mechanism of nickel base superalloy,the threedimensional mechanical model in the process of gun drilling is established,the cutting force is numerically calculated,the correlation mechanism between the inner and outer corners of the tool,the width of the inner and outer cutting edges and the radial force is analyzed,and the influence law of the geometric parameters of gun drilling on the cutting force is given.Secondly,based on GH4169 nickel base superalloy,a finite element model of drilling is established to numerically simulate the mechanical behavior during drilling.In order to clarify the primary and secondary factors affecting the axial force and torque of the gun drill,a three factor and three-level orthogonal test was designed.Through multiple regression analysis of orthogonal test data,a predictive model of axial force and torque for drilling small holes in nickel alloy was established,and the effect of machining parameters on axial force and torque was analyzed.,and the optimal scheme of simulation test is given.At the same time,in order to explore the influence behavior of cutting heat on cutting force,a thermo-mechanical coupling model was established,the temperature distribution law of the drill bit during the process of gun drilling nickel-based superalloy was analyzed,and the optimal machining parameter range was determined: under the same spindle speed,the feed rate is 0.1?0.3mm/s.Finally,according to the actual machining test,the above established finite element model is verified.It is determined that the feed speed has the greatest influence on the axial force and torque,followed by the speed.Appropriately increasing the speed can reduce the axial force and torque,and the scheme to improve the drilling performance is given.