Chatter Suppression Of Blisk Belt Grinding And Optimization Of Terminal Contact Force Control Module

Blisk is one of the key parts of modern aero-engine.The surface quality of the blade directly affects the life and safety performance of the aero--engine.Due to the high strength of the blisk material,the complex profile,the narrow spacing between the blades,the thin and slender blades,the precision machining of blisk has been a major problem in the industry.The traditional aero-engine blisk is formed by precision forging.After blade forging,the precision of the blade profile cannot meet the requirements of the use.Generally,it needs manual polishing.However,artificial buffing aero-engine blades can lead to a series of problems such as poor product consistency and low machining efficiency.The combination of grinding and polishing multi-axis CNC machine,and new open-type abrasive belt grinding technology is an ideal solution for machining aero-engine blades.Due to the unique structure of the blisk grinding end contact force control function module,causing varying degrees of chatter in the grinding of the blisk by a belt grinder,resulting in the formation of chatter marks on the surface of the aero-engine blade,which have a great influence on the surface roughness,profile accuracy,and surface morphology of the aero-engine blade.This paper is aimed at the optimization of belt grinding chatter of the blisk.The study is aiming at the end-to-end contact force control function module of the belt grinding of blisk.The function module of the terminal force control is redesigned through three-dimensional modeling and structural optimization.The structural layout of the end force control function module is changed to avoid the overlap of the natural frequency between the blade and the contact bar and wheel,which reduces grinding chatter.The effectiveness of the method is verified by experiments.The specific work having done in this paper is as follows:(1)The causes of belt grinding chatter in the grinding of the blisk is analyzed,and the main reasons for the formation of chatter in the contact force control function module at the end of grinding of the entire bladed blade is found.On the basis,the physical model of the blisk grinding process is derived,and the analytical formula of the resonant frequency of the end contact functional module system formed by the blisk and the contact wheel/rod during grinding is deduced.(2)A three-dimensional model of the contact force control function module of the blisk abrasive belt grinding is established.The static and dynamics analysis is performed on the end-to-end contact force control function module of the belt grinding of blisk.The resonance frequency of the end-to-end contact force control function module of the belt grinding of blisk is obtained.(3)The mathematical model of the contact force and contact wheel of the end-to-end contact force control module of the blisk abrasive belt grinding is established by using the variable density theory topology optimization method.The maximum stiffness of the contact bar and wheel structure is used as the optimization goal,and the contact force control function module for the end contact is established.The topology optimization design is performed to avoid the resonance frequencies of the blisk blade and the contact bar and wheel module components.The optimal structural layout of the end-to-end contact force control function module of the belt grinding of blisk is obtained.(4)Aiming at the end-to-end contact force control function module of the belt grinding of blisk before and after optimization,the orthogonal test design method is used,which taking the belt line speed,feed speed,positive grinding pressure,and contact wheel hardness as variables and the amplitude of the blisk grinding process and the surface roughness,profile accuracy and surface micro-morphology of the blade after grinding as the evaluation index.The effectiveness of the optimization method proposed in this paper is verified.