Design And Research Of Blade Grinding Device For Aeroengine Compressor

As a key component of aero-engine,blade plays an important role.The quality of blade is the precondition for the efficient and safe operation of aero-engine.It is known that the blade,composed with twisted complex surface,requires a high precision.Therefore,every process should be complicated and critical,during the procedure of designing and manufacturing.Nowadays,the hardest issue for China is the manufacture of the blade instead of its design.Blade grinding,the last process of blade shaping,relies on manual grinding and polishing by workers,leading to unassuerd efficiency.Therefore,in order to improve the efficiency of the blades when they are polished,a set of hybrid grinding and polishing device is designed for compressor blade.First of all,start with the blade itself.Using reverse engineering technology to complete the reverse modeling.After obtaining a large number of blade point cloud by 3d scanning,the method of median filtering algorithm and uniform sampling method are used to denoising and simplify the data.The processed point cloud data is fitted with the method of cubic b-spline global approximation to fit a cross section profile.A complete 3D model of compressor blade was obtained by lofting the section profile formed with different blade heights in SolidWorks.Based on UG secondary development and surface differential geometry theory,the grinding path planning of compressor blade was completed.Secondly,according to the structural characteristics of the compressor blade,determine the size of the moving platform of the parallel mechanism in the hybrid device.The detailing of the driving rod of the 3-RPS parallel mechanism should meet its working space,and then the assembly of 3-RPS parallel mechanism as a whole could be completed.Similarly,the cross slide screw and abrasive belt grinding device are designed and assembled.On completing the selection of important parts and components,an integrated blade hybrid gringing device in 3D software is composed.Kinematics analysis is performed on the 3-RPS parallel mechanism to obtain the positive and negative solutions of its position,velocity,and acceleration.With ADAMS,the kinematic positive and negative solutions of 3-RPS parallel mechanism are simulated.Obtaining the time-varying curve of the displacement,speed,angular velocity,and angular acceleration of the moving platform and driving rod.Meanwhile,the movement laws of driving rod and moving platform are studied while the profile of blade was polished,and use ADAMS software simulation verification.The maximum workspace of the 3-RPS parallel mechanism and the hybrid grinding device were obtained on combining Monte Carlo method and Limit boundary search method.The results show that device meets the requirement of working space during the grinding of the compressor blades.Finally,a finite element model of a 3-RPS parallel platform and a hybrid grinding device was established.On using the static analysis and modal analysis are realized by ANSYS Workbench finite element software,the stress-strain diagrams of the moving platform at different positions and the vibration pattern diagrams in different orders are obtained.From the stress-strain diagram,it can be seen that the stiffness of both parallel mechanism and mixed grinding device all meet the requirements of working conditions.After analyzing the natural frequencies of different orders and the vibration patterns,a method to avoid resonance is proposed.