Research On The Dynamic Characteristics Of The Hard Milling Process For Automobile Panel Die

Automobile panel has the characteristics of large size and high precision.And it made the most complex process in most important parts of the car.The Hardened Mould belongs to typical high strength,high hardness materials.This paper studies the hardness of hardened steel mould insert type is defined by different materials and different hardness by finishing milling surface to the hardened mould process requirements.The assembly sequence and processing method of calibration by splicing gap hardened steel mold 0.02 mm was taken.This form of hardened steel molds are widely applied in large-scale automobile parts.Due to the existence of poor hardness,hard milling process,the impact of the strong force of the tool wear,milling vibration control will lead to the process of accelerated,and even the damage of the knife body.In the process of machining the die with insert block,the hardness of the workpiece will further aggravate the damage degree of the tool.If the process parameters and conditions are not appropriate,even the whole body will be broken when the serious.Therefore,the different degree of tool failure seriously restricts the high quality machining.This paper studies the milling force multihardness splicing hardened steel mold milling process in milling process due to mutation,splice vibration,vibration and the milling hardness difference caused by increase tool wear and reduce surface quality problems.In this paper,the study of milling force mutation and milling chatter simulation are carried out,and the milling stability region is simulated and verified by the experimental methodFirstly,the milling force model of ball end milling cutter is established based on the geometric model of ball end milling cutter and the mechanical constitutive model.The milling force coefficient of different hardness is obtained by the identification test.Secondly,different hardness of materials and different parameters areestablished multihardness splicing hardened steel milling based on the finite element model.The influence of different milling direction on the milling force is simulated,and the correctness of the simulation model is verified by experiments.Single factor experiments were carried out to study the effects of different cutting parameters on the milling force.Orthogonal test method was used to optimize the cutting parameters.Thirdly,the use of dynamic stability analysis method to establish a prediction model of multihardness splicing hardened steel milling stability,simulation of multi hardness stability curve,analyzes the influence of modal parameters on milling lobe shape,then the accuracy of milling vibration signal to determine the stability curve obtained by milling experiments.Finally,the surface quality of the workpiece obtained by the milling test and the tool wear were observed to analyze the relationship between milling chatter,surface topography and tool wear.