| Manufacturing industry is an indispensable part of economic development.Machining is the foundation of manufacturing industry.With the process of China's modernization,the country has higher and higher requirements for manufacturing industry.Therefore,the proportion of precision machining and special machining in machining is also more and more important.Because of its high strength and hardness,304 stainless steel can ensure the accuracy and the formability of the workpiece under the condition of high temperature and high pressure.It can adapt to various corrosive environments such as acid and alkaline environment,and it is used in more and more occasions.However,stainless steel has large plasticity,high toughness and poor thermal conductivity,so the plastic deformation is serious during turning.It is easy to produce crystal shift and crystal lattice distortion and work hardening phenomenon.It belongs to difficult to process materials.It is difficult to meet the machining requirements when the traditional turning is used because the cutting force is too large and the work hardening is easy to occur,and the surface quality is low.Therefore,as a new machining method,ultrasonic assisted turning has been paid more and more attention.In view of the scarcity of special ultrasonic turning machine tools in China,the manufacturing cost is higher.In this paper,the cutting force is studied by simulation,and the correctness of simulation is verified by dry ultrasonic assisted turning of 304 stainless steel shaft parts.In order to support the development and application of ultrasonic assisted turning of stainless steel,the effects of ultrasonic assisted turning and traditional turning on the surface roughness and chip of workpiece are compared.The main research points of this project;1.This paper reviews the research process and achievements of ultrasonic assisted machining at home and abroad,including the research status of ultrasonic vibration system,ultrasonic assisted turning and ultrasonic assisted turning in difficult to machine materials.The advantages of ultrasonic assisted turning system and traditional turning system are pointed out.2.Research on the mechanism of ultrasonic assisted turning,including kinematic analysis,surface formation mechanism and cutting force generation mechanism.According to the machinability of 304 stainless steel,the cutting mechanism is analyzed to reduce the cutting force.3.Finite element analysis of cutting force in ultrasonic assisted turning.By using Ansys finite element analysis software,the ultrasonic assisted turning of 304 stainless steel is simulated.The change of cutting force and stress under ultrasonic vibration is analyzed.4.Based on the analysis of ultrasonic assisted turning experiment,the existing ultrasonic vibration system and ultrasonic assisted turning equipment of CNC machine tool components are selected,and the reasonable workpiece,vibration parameters and machining parameters are selected for dry turning of 304 stainless steel.The correctness of simulation is determined by comparing experimental parameters with simulation parameters.The influence of ultrasonic parameters and machining parameters on the surface roughness and chip is analyzed by comparing the chip produced by ultrasonic assisted turning and traditional turning,and the surface roughness of workpiece.The advantages of ultrasonic assisted turning are summarized. |
PDF Full Text Request