Machining Technology Of Cooling Air Film Holes On Turbine Blades Of Aero Plane Engines

The heart of the aircraft-aircraft engines, determines the performance of the aircraft, and one of the key indicators is its thrust-weight ratio, which directly determines the function of fighter airplanes. So the development of aircraft engines affects the development of the aircraft in the long run. With the increasing requirement of thrust weight ratio of gas turbine engine, to improve thermal efficiency has become a critical aspect, which challenges the high-temperature-resistant function of the materials. The effective solution is to adopt cooling protection technology to reduce the local part temperature, so that the same material can be used at a higher-temperature working environment. Turbine entrance gas temperature has improved from1000K of generation I to2000K of generation II, so the increase in the entrance temperature is a severe test on the material. As "heart" of the aircraft engine, turbine blades play an important role in the performance of the aircraft engines.Film cooling is a very effective means of cooling. This essay studies the machining technology of turbine blade film hole cooling, and focuses on analysis of the parameter selection in high-pressure turbine blade film hole machining process and how to remove the remelted layer by spark punching. Considering the shape, size of film holes and equipment condition, the author adopts high-speed drilling EDM machining technology, which improves of the company’s original eight-axis CNC high-speed EDM drilling machines and enhances the X, Y axis positioning accuracy, repeated-positioning accuracy and backlash. In the spark punch experiment, orthogonal test is applied and the analysis is based on four main EDM drilling machining parameters, including machining current, pulse width, pulse interval, servo feed rate. According to the test data, this technology solidifies the optimum parameters of machining film holes.This essay focuses on the analysis of the harmful effects of remelted layer on the products’quality, and introduces the method of removing it. According to the structural features of the blade, combined with the difficult machining features of high-temperature alloys, the author applies the extrusion Abrasive Flow Machining process test. After analyzing the machining features of removing remelted layer by abrasive flow, the author takes the amount of increased aperture as a standard to test the remelted-layer removal situation. According to accumulated experimental data, a conclusion can be drawn that when theΦ0.3hole abrasive flow aperture increases to0.04mm, no micro crack is found on all the holes; when Φ0.5hole abrasive flow aperture increases to0.02mm, remelted layer are removed from all apertures, and there are radius at entrances and exits. This meets the design needs.The result of this study has been applied to production. Compared with the previous film hole machining, the product quality and blade manufacturing standards have been improved significantly. This technique has been promoted in this field, and provided theoretical and technical support for the turbine blades manufacture of aircraft engines.