Modeling Simulation And Testing On Milling Force Of Jointed Die In Consideration Of Tool Wear

Along with the automobile parts surface is complicated,the mold cavity will lead to the emergence of a large number of concave grooves and other parts of the structure,the overall processing will cause the cavity damage and reduce the service life of the mould,at the same time also easy to appear crack,galling wear serious problem.Usually,in the milling process,according to the stress characteristics required by different positions,most of the inserting die parts are assembled after the whole machining.However,because of the existence of hardness difference at the joint,there will be complex changes in the milling force.These changes will cause tool wear and milling vibration to increase in a short time.Based on the above problems,this paper mainly studies the modeling and testing on milling force of jointed die in consideration of tool wear,cutting force under different tool wear prediction,at the same time through a hardened steel mold milling experiments splicing response research on milling force and vibration characteristics of tool wear and provide the theoretical basis for the processing of complex shape parts.The main contents are as follows:Based on the metal cutting principle and the mechanical model,a single hardness ball-end milling force model is built on the basis of the shear force model and the friction stress model.The model mainly takes into account the tool flank wear in the actual machining.The milling force coefficient is identified with the same material and different hardness of hardened steel that used the mean milling force method.At the same time,it is also the modeling foundation of the milling force model of the jointed die with different hardness.Ball-end milling force model based on joint is built,which takes into account the tool flank wear.Since cutting jointed area of the ball-end mill is cutin and cut-out two times,the impact force of the joint area is introduced in thismodel.The milling process of ball-end mill is divided into different areas,and then the cutting thickness is calculated in different milling area.Finally,the resultant force of milling force is obtained through axial micro integration of milling force.The milling force model considering tool wear is predicted by simulation software,and the milling force experiment of the hardened steel ball-end mill is carried out,and the accuracy of the milling force model is verified.The changing rule of milling force under the same material hardness and different tool wear is analyzed.Meanwhile,the influence of tool wear on milling force of joint area is also analyzed.The experiment of milling vibration is carried out,and the influence of tool flank wear on the vibration characteristics of the system is mainly studied.Due to the tool vibration affects surface quality,a single factor experiment is carried out in this paper.Vibration acceleration,vibration waveform and acceleration spectrum are selected to quantitatively analyze the changing rule of different tool wear on the vibration characteristics of multi hardness jointed die.The inner reason of the milling vibration is discussed by comparing the vibration signals of different hardness regions and jointed area.The research results are the theoretical basis and the basis for the research and control of the tool wear in the milling process of the ball-end and the improvement of the stability of the milling process.