Method for machining turbine blade expansion holes through electric spark milling

Abstract

The invention discloses a method for machining turbine blade expansion holes through electric spark milling. The method comprises the steps that a turbine blade three-dimensional model is preset; a turbine blade is installed, and the theoretical point taking orientation is measured; the corresponding preset turbine blade three-dimensional model is fitted according to the theoretical point taking orientation, hole positions, hole shapes and the number of the holes are determined, and corresponding machining electrodes are selected; the machining electrodes are subjected to loss testing and correction compensation; the machining electrodes are controlled for alignment machining to obtain single machining holes consistent with the three-dimensional model according to the three-dimensional model; and feeding and milling of the machining electrodes are repeatedly controlled till all the machining holes are machined. According to the method, the three-dimensional model is preset, then the turbine blade is subjected to configuration detection and matched with the corresponding three-dimensional model, the positions, shapes and number of the actual machining holes are determined, the corresponding machining electrodes are selected for alignment machining, and the positions, shapes and number of the machining holes are consistent with those of the three-dimensional model. The positionsare regular, the shapes are unified, and the machining technology indexes of the turbine blade expansion holes reach a high level.

Description

technical field [0001] The invention relates to the technical field of machining turbine engine workpieces, in particular to a method for electric discharge milling to process expansion holes of turbine blades. Background technique [0002] Air film cooling is a cooling technology applied to gas turbine blades. It is mainly to design a large number of air film holes on the leading edge of the turbine blade and the blade body surface. The hole diameter is generally 0.2-0.8mm, and the space angle is complicated. The high-pressure cold air is extracted from the high-pressure stage and transported to the inner channel of the blade. The cold air strengthens the convection heat transfer in the channel and takes away part of the heat. At the same time, a part of the cold air is ejected from the air film hole on the blade wall. Under the action, it bends downstream, adheres to the blade wall, forms a cold air film with a lower temperature, isolates the wall from the high-temperature...

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Problems solved by technology

[0004] Based on this, it is necessary to provide a method for EDM machining the expansion hole of the turbine blade to solve the problem of irregular position and non-uniform shape of the expansion hole of the turbine blade. By designing the hole model and writing a program, the bottom hole is cut by an EDM machine tool. The hole and the expansion hole are processed together to make the expansion hole of the turbine blade regular in position and uniform in shape to meet the theoretical design requirements

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