Study On The Machining Process Of An Extended Casing

As we know,aero engines have thousands of parts due to their different functions.To lighten the weight of aero engine,most casings are thin-wall.Also,some intractable materials,such as titanium alloys and Super alloys,are widely used in aero engines.Hence,long processing cycle and difficult to be machined are the main problems of the process of manufacturing an aero engine.Due to the feature of large diameter and thin wall,the parts deform much more easily during the process of manufacturing,which leads to parts are more difficult to be machined.As a whole,this paper analyzes the casings aiming at aero engine casings.Then,the paper briefly introduces some typical aero engine casings,according to their structure,such as integral annulus casing,split casing and casing with struts.Next,the manufacturability of different types of casings is discussed and the general principles of process routes of casings mentioned above and their features in CNC machining are analyzed.After briefly researching and analyzing manufacturing process of aero engine casings,taking a typical casing for an example,the paper comprehensively analyzes the manufacturing process and production demand,which guarantees the quality of part and satisfies the demand of parts from developing to mass production.The author selected a typical HPC extension casing as the carrier.At the beginning of developing aero engine,it is enough that satisfies the size and technical requirements of the design drawing.Lacking understanding of machining and machining features and high requirement of machining efficiency and process cycle,a relatively long process route was made,which removed materials step by step and dispersedly to guarantee the quality of casings as high as possible.In order to satisfy the mass production demand,the author simplified and optimized the process route by accumulating experience.During the period of optimization and verification,there were several unstable factors which would influence the quality of the casing.The deformation of some casings after finish turning inner surfaces is the main problem.Aiming at this problem,the author concluded and analyzed the data of size and technical conditions.To solve these problems,the author designed three different plans to optimize the process route further by considering the features of part structures and analyzing the factors which would lead to the deformation at this period.Comparing these three plans with each other,the author chose the most reasonable one which achieved the requirements of stable mass production.As advanced machines are used and technologies are applied,the manufacturing efficiency and quality need to been improved to a higher level due to the increase of the quality of aero engines.For example,milling-turning process,high speed milling and adaptive machining have been applied in the process of extension casing.The author initially mastered these advanced manufacturing methods of intractable material thin-wall casings,such as milling-turning and other high efficiency machining methods in the casing.Both manufacturing efficiency and quality have improved a lot.What’s more,it also builds the foundation of enlarging the application of such technologies in other casings.