Electric discharge modeling method for shrouded impeller

Abstract

The invention discloses an electric discharge modeling method for a shrouded impeller, and relates to the technical field of electric discharge machining. The modeling method comprises the following steps of mounting a workpiece, aligning hole sites, machining a conical hole, machining a cylindrical hole and finishing machining. According to the method, a tool electrode assembly is arranged on an adjusting mechanism, and after the output end of an electric cylinder is reset and returned, all the flow direction of working fluid is changed into the mode by which the working fluid rushes out from an oblique flow hole in a first electrode obliquely downwards, rushes into the single-side direction in the cylindrical hole, then rushes out from the other side of the first electrode after passing through an area below the first electrode in the hole. Electric corrosion products in the deep cylindrical hole can be effectively discharged in the flow direction, so that the arc discharge or short circuit phenomenon is avoided, and the hole wall quality in an air film hole is ensured; and by arranging a mechanical arm and the adjusting mechanism, the oblique interference part of a workpiece can be avoided, and it is guaranteed that the air film hole is smoothly machined in the to-be-machined position of the joint between a blade body and a blade crown of the workpiece.

Description

technical field [0001] The invention relates to the technical field of electric discharge machining, in particular to an electric discharge forming method for a crowned impeller. Background technique [0002] The working conditions of the internal turbine blades of the aero-engine are very harsh, and they rotate at high speed under the impact of high-pressure corrosive gas. The structure mainly relies on the cooling film holes opened on the end surface for cooling. The existing technology usually uses EDM technology to process the blades. The microporous machining of cooling gas film holes means immersing and positioning the workpiece in the EDM working fluid, using the rotating integrated electrode to directly process the tapered holes and cylindrical holes on the processing surface, and at the same time, through the integrated ultrasonic vibration assisted Equipment to discharge the electro-corrosion products generated during the EDM process. [0003] However, during the ...

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Problems solved by technology

[0003] However, during the long-term modeling and processing of crowned impeller blades, our company found that the existing technology still has certain disadvantages: 1. The structure of the gas film hole is small and deep, and before the end surface of the gas film hole is completely opened, the ultrasonic vibration It can only cooperate with the working fluid to bring out the electro-corrosion products on the side of the one-piece electrode near the orifice, but the electro-corrosion products located at the lower part of the one-piece electrode with a relatively large height and diameter in the hole cannot be effectively eliminated, resulting in arcing or short circuit. It affects the quality of the hole wall in the lower part of the air film hole; 2. Since the blade crown of the shrouded impeller is longer than the blade body of the blade, and the junction of the two has a certain structural angle, the integrated electrode is processed. There is an interference phenomenon at all times, and there is air flow interaction between the processed interference air film hole and the rest of the cooling air film hole, which leads to the cooling effect of the blade to be improved

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