Turbine blade dovetail groove machining method capable of aligning center

Abstract

The invention provides a machining method of a turbine blade dovetail groove capable of centering, which comprises the following steps: designing a centering electrode, machining a special electrode for the dovetail groove, designing an auxiliary centering cylindrical pin with the diameter of phi 1 at the bottom of the electrode, and enabling the center of the centering pin to pass through a symmetric plane of the electrode so as to ensure accurate centering. According to the machining method capable of aligning the center, before machining, the center of the auxiliary hole is aligned through the centering function of a machine tool, and the dovetail groove which is symmetrical relative to the center of the auxiliary hole is machined through programming with the auxiliary hole as the center. The turbine blade dovetail groove machining method capable of aligning the center has the advantages that programming alignment machining of the dovetail groove is achieved, and the debugging period of parts is shortened by 70%; operation and mastering are easy, and dependence on the operation skill level of workers is greatly reduced; and the machining qualification rate of the dovetail groove is improved by 30%.

Description

Technical Field

[0001] The invention relates to the field of special electrodes and processes for centering dovetail grooves of turbine blades, and in particular to a method for processing dovetail grooves of turbine blades that can be centered. Background Art

[0002] The working blades of high-pressure turbines have a complex inner cavity structure. In order to ensure that the core strength meets the casting requirements or the core stripping is smooth during the casting process, it is generally necessary to design one or more casting process holes on the bottom end face of the tenon, and then seal the process hole later. The sealing method is generally to process a dovetail-shaped groove on the basis of the process hole. The dovetail groove has a small structural size, a straight surface on the back side of the basin (Y direction), and a degree surface on the intake and exhaust side (X direction). Use pressure to press the curved sealing plate into the dovetail groove. After the pressure flattens the curved plate, the plate is clamped by the slope of the dovetail groove wall in the X direction. The symmetry center of the dovetail groove must be consistent with the symmetry center of the process hole to ensure that the plate is reliably embedded. According to the position and shape requirements of the dovetail groove, the present invention designs an alignable electrode and a processing technology that can meet the processing requirements of this type of dovetail groove. Summary of the invention

[0003] The purpose of the present invention is to ensure simple operation and accurately process a dovetail groove whose symmetry center is consistent with the symmetry center of a process hole, and particularly provides a turbine blade dovetail groove processing method capable of finding the center.

[0004] The present invention provides a method for machining a dovetail groove of a turbine blade capable of finding a center, and the technical solution includes the following contents:

[0005] 1) Design of electrodes that can find the exact center

[0006] The electrode is specially designed for dovetail groove processing. The bottom of the electrode is designed with a diameter of The center of the auxiliary alignment pin passes through the symmetry plane of the electrode to ensure accurate alignment. Figure 1 .

[0007] 2) Processing method that can find the exact center

[0008] Before processing, use the centering function of the machine tool to find the center of the process hole, and program and process a dovetail groove that is symmetrical relative to the center of the process hole with the process hole as the center.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] The method for machining dovetail grooves of turbine blades capable of centering described in the present invention realizes programming and centering machining of dovetail grooves, shortening the debugging cycle of parts by 70%; it is easy to operate and master, and the dependence on the operating skill level of workers is greatly reduced; the qualified rate of dovetail groove machining is increased by 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0012] Figure 1 This is a schematic diagram of the electrode structure that can find the exact center;

[0013] Figure 2 Schematic diagram of dovetail groove structure;

[0014] Figure 3 It is the schematic diagram for aligning the dovetail groove in the Y direction;

[0015] Figure 4 This is the schematic diagram for aligning the dovetail slot in the X direction;

[0016] Figure 5 Schematic diagram of the dovetail groove processing steps. DETAILED DESCRIPTION

[0017] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0018] 1. Determine the position of the dovetail groove in the Y direction: Figure 3 As shown, use the electrode alignment pin to touch the hole wall in the Y direction of the process hole, use the centering function of the machine tool to determine the position of the dovetail groove in the Y direction, and clear the Y direction of the machine tool to 0.

[0019] 2. Determine the position of the dovetail groove in the X direction: Figure 4 As shown in the figure, after determining the Y direction position of the dovetail groove, move the electrode when the Y axis = 0, use the electrode alignment pin to touch the hole wall of the process hole in the X direction, use the centering function of the machine tool to determine the X direction position of the dovetail groove, and clear the X direction of the machine tool to 0.

[0020] 3. Dovetail groove processing

[0021] First, at the position of X-axis = 0 and Y-axis = 0 of the machine tool, the electrode moves downward, and after the discharge machining reaches the designed depth of the dovetail groove, the electrode moves in the negative direction of the X-axis to perform the groove expansion discharge machining until the specified size is reached. See attached. Figure 5 (a).

[0022] Then, the electrode rotates 180° around the Z axis, and at the position of the machine tool X axis = 0, Y axis = 0, the electrode moves downward, and after the dovetail groove is processed to the designed depth, the electrode moves in the positive direction of the X axis to perform slot expansion EDM until the specified size is reached. See attached. Figure 5 (b).

[0023] Matters not covered by the present invention are known technologies.

[0024] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for machining a dovetail groove of a turbine blade capable of finding a center, characterized in that: Specifically include the following: Electrode that can be found exactly at the center: The electrode is specially designed for dovetail groove processing. An auxiliary alignment cylindrical pin with a diameter of φ1 is designed at the bottom of the electrode. The center of the alignment cylindrical pin passes through the symmetry plane of the electrode to ensure accurate alignment. Processing methods that can find the exact center: Before processing, use the centering function of the machine tool to find the center of the process hole, and program and process a dovetail groove that is symmetrical relative to the center of the process hole with the process hole as the center.

2. The method for machining a turbine blade dovetail groove capable of being centered according to claim 1, characterized in that:

1. Determine the position of the dovetail groove in the Y direction: Use the electrode alignment pin to touch the hole wall in the Y direction of the process hole, use the centering function of the machine tool to determine the position of the dovetail groove in the Y direction, and clear the Y direction of the machine tool to 0; 2. Determine the position of the dovetail groove in the X direction: After determining the position of the dovetail groove in the Y direction, move the electrode when the Y axis = 0, and use the electrode alignment pin to touch the hole wall in the X direction of the process hole. Use the centering function of the machine tool to determine the position of the dovetail groove in the X direction, and clear the X direction of the machine tool to 0; 3. Dovetail groove processing: At the position of X-axis = 0 and Y-axis = 0 of the machine tool, the electrode moves downward, and after the discharge processing reaches the designed depth of the dovetail groove, the electrode moves in the negative direction of the X-axis to perform the groove expansion discharge processing until the specified size is reached; The electrode rotates 180° around the Z axis, and at the position where the machine tool X axis = 0 and the Y axis = 0, the electrode moves downward. After the dovetail groove is processed to the designed depth, the electrode moves in the positive direction of the X axis to perform groove expansion discharge machining until it is processed to the specified size.

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