关键词: 航空发动机叶片, 前后缘, 电火花加工, 点云数据, NURBS, 加工误差分析

Abstract: There is machining errors in the leading and trailing edges of aero-engine blade after Electrochemical Machining (ECM).Electric Discharge Machining (EDM) technology was proposed to trim the leading and trailing edges of blade to reduce machining errors,and then the machining errors of leading and trialing edges were analyzed.The self-developed six-axis EDM machine was used to trim the trailing edges of blade by an electrode with curved surface.The point cloud data of blade surface was collected using a set of Coordinate Measuring Machine (CMM).The Genetic Algorithm (GA) and Iterative Closest Point (ICP) algorithm were used to register the blade point cloud data after envelope processing with the theoretical model of blade,and the least square ellipse and NURBS curve fitting were used to process the point cloud data.Aiming at the fitted blade contour curve after machining,the machining errors at the trailing edge of the blade and the overall trend of machining errors were reflected by taking equidistant points on the curve and calculating the distance between these points and the theoretical contour of the blade.The results show that the profile error of the trailing edge of the blade is between-16.4~88.5 μm,and the average error is 53.7 μm.The profile error at the edge head of the trailing edge of the blade is the smallest,which verifies the feasibility of the EDM technology to cover the leading and trailing edges of the blade.

Key words: aero-engine blade, leading and trailing edges, EDM, point cloud data, NURBS, machining error analysis