Research On Machining Parameters Optimization For Complex Surface Milling Based On Milling Force Prediction Model

Milling is an indispensable processing method in advanced manufacturing industry.The research on the basic theory and optimization method in it is of great significance to improve the quality and efficiency of machining.In order to improve the applicability,accuracy and efficiency of the feed rate optimization method,the influence analysis and optimization method of machining parameters based on milling force prediction model are studied in this paper,including modeling method of milling force oriented to tool position information input and the feed rate optimization method for constant milling load constraints,so as to provide theoretical support for parameter optimization in milling process.At present,most of the milling planning methods make feed rate constant,which inevitably leads to low overall processing efficiency.In view of this,a feed rate optimization method for constant milling load constraints is proposed.The machining requirements and corresponding constraints in each stage of milling are analyzed.According to the constraints,the milling force model is used to control the feed rate to optimize the tool path file.A general milling force modeling method is proposed by using geometric analysis.The cutting edge is discretized into a series of infinitesimal cutting edges in polar coordinates,so as to use the oblique cutting force model for equivalent calculation.The milling force is calculated by integrating.A modeling method of oblique cutting force based on surface fitting is proposed,the cutting force model of AISI-1045 steel is established by a series of cutting experiments.Aiming at the rough milling stage,a milling force and torque model of cylindrical end mill based on cylindrical coordinates is established,and the influence of axial cutting depth on milling force is studied.Firstly,the geometric model of tool and workpiece in milling is established in cylindrical coordinates.Then the cutting edge is discretized into a series of infinitesimal cutting edge,and the infinitesimal cutting force is calculated by using the oblique cutting force function.Finally,the milling force and torque acting on the tool are calculated by integrating the cutting force acting on the infinitesimal cutting edge in cutting.Based on the model,the periodic influence of axial cutting depth on milling force is analyzed,and the calculation method of axial cutting depth period and its expression form are proposed,which provides theoretical support for the optimization of axial cutting depth.Finally,the validity of the model and the correctness of the periodicity law are verified by the side-edge milling experiments.Aiming at the semi-finishing and finishing milling stage,a milling force and torque model of ball end mill based on spherical coordinates is established,and the influence of machining attitude on milling load is studied.The geometric model of tool and workpiece in milling is established in spherical coordinates.The milling force and torque acting on tool are calculated by discreting the cutting edge and integrating the infinitesimal cutting force.The three vector positioning method is proposed to describe the machining status,which makes it easy for the model to accept the machining information in the tool path file.At the same time,it supports the accurate description of variable cutting depth,variable attitude and following cut cases.The influence of machining attitude on milling radial force and torque is analyzed based on the model,and the milling load response surface is drawn to intuitively analyze the suitable machining attitude for different machining stages,which provides theoretical support for the optimization of machining attitude.Finally,the validity of the model is verified by groove milling and curve milling experiments.Aiming at complex surface milling,a feed rate optimization method based on milling state response surface is proposed.The milling torque and radial force are used as constraints according to the requirements of each machining stage.The milling moment is predicted by the moment model with cutter location file as input.The appropriate torque value is selected as the torque constraint according to the machining stage.The feed rate is controlled by the moment model,in order to optimize the tool path file.The response surface of milling state,moment and speed is drawn to record and handle a large number of machining information in tool position file,so as to greatly improve the optimization efficiency under the premise of ensuring the optimization effect.Finally,the effectiveness of the proposed method for improving the milling quality and efficiency is verified by the impeller machining experiment.The modeling method of cutting force and milling force and the analysis and optimization method of machining parameters are universal,which can be extended to other milling tools and metal materials.The established model and optimization method provide theoretical support for parameter optimization in milling process and have great application effect.It not only helps to improve the processing quality and efficiency in milling,but also lays a firm foundation for further realizing the digitalization and intellectualization of milling.