Research On Tool Path Of Impeller Machining Based On Parallel Robot

As the core component of centrifugal compressor,turbo engine and large fan,the impeller is widely used in energy power,steel smelting,aerospace and other fields.As a typical channel-type thin-walled part,the impeller surface processing method and accuracy will directly affect the aerodynamic performance of the machine,so it is necessary to precision machine the impeller.The difficulty of impeller machining is mainly concentrated on the thin blade,narrow flow channel space,complex surface modeling and high processing precision.The five-axis CNC machine tool has high processing efficiency and good milling flexibility.It is widely used in all kinds of impeller manufacturing,but it costs a lot of money for millions of machine tools and maintenance costs.Many small mold factories can not afford that.This project is based on the existing modular reconfigurable six-degree-of-freedom slider parallel robot in the laboratory.The electric spindle with milling shank device is installed at the end of the motion platform to expand the application range of the robot instead of the expensive CNC.The machine tool realizes the processing and manufacturing of the impeller to achieve the purpose of reducing the production cost of the enterprise.This topic firstly establishes the impeller mathematical model in the UG environment based on the NURBS curve and surface construction theory,and clarifies the process specification,machining process and tool selection of the impeller machining.On this basis,the tool path in Cartesian coordinate space is planned.Several interpolation points are added to the tool path curve,and interpolation operations are performed between adjacent interpolation points to make the tool move accurately according to the preset track.The kinematics model of the parallel robot is established by geometric analysis.The conversion relationship between the position,velocity and acceleration of the tool position during the machining of the impeller between the tool coordinate system and the robot body coordinate system is obtained.In order to avoid the machining failure at the singular point or the blank to be processed in the dead space,it is necessary to determine the working space of the parallel robot.Finally,the impeller platform is built on the existing modular reconfigurable parallel robot in the laboratory,and the control system is designed for the processing platform.A machine tool model based on a parallel robot is built in VERICUT to make the tool move according to the expected trajectory and realize the virtual machining of the impeller.