Research On Machining Technologies Of Robotic Automatic Grinding For Blades

As one of the key parts of aero-engine,blade has been working in the harsh conditions of high temperature,high pressure and so on,and its quality determines the aero-engine's working performance and service life directly.The grinding processes of blade now include:manual grind,CNC belt-grinding machine system,industrial robotic belt-grinding system.Manual grind requires higher skills for workers,causing lower machining efficiency,and it can not guarantee the machining quality of blade effectively;Grinding by CNC belt-grinding machine system can improve the machining accuracy,and it is widely used for large blades,but the cost is higher at the same time.Grinding by robotic belt-grinding system can obtain a higher machining efficiency,better processing consistency and lower cost.Therefore,it is a effective way to grind blades by industrial robotic automatic grinding system.This paper focuses on the key technology of robotic automatic grinding for blades.The main research contents are as follows:?1?Self built for robotic belt-grinding system.According to the coordinate transformation relationship based on the system,a new set of fixtures were designed,which could make the translation of workpiece coordinate system?T_g?relative to flange plate coordinate system?T₆?only with position translation without pose rotation,simplifying the calculation.?2?A mathematical model was established based on the characteristics of belt grinding,and the motion equation of single grain was deduced,then the motion equations of multiple abrasive grains were obtained.The surface profile of the workpiece along the feed direction was acquired through MATLAB.The influence of grinding parameters,such as grain numbers?M?,belt speed?V_s?,workpiece feed speed?V_w?and grinding depth?a_p?,on surface roughness were gained.?3?The methods of describing the robot end position-posture in robot motion space were studied.The translation of workpiece coordinate system from homogeneous transformation matrix to RPY angle was carried out through the Robotics Toolbox of MATLAB.Several trajectory planning methods of robotic belt-grinding for blades were introduced.According to the characteristics of blade used in this project,the grinding area was rational divided.The iso-planar method was used to generate grinding trajectory,scattered processing points were acquired by equal step method,and robot processing code was generated by robot off-line programming software in combination with the requirements of robotic gesture during grinding.?4?By using the robotic belt grinding system,the aluminum alloy grinding experiment was carried out.Surface roughness under different processing parameters was acquired respectively and compared with the simulation value to vertify simulation accuracy.According to the technology requirements,choose rational processing parameters to complete the blade grinding process.