A six-point positioning detection method for turbine blades

Abstract

The application provides a turbine blade six-point positioning detection method, which comprises the following steps: obtaining six final positioning points on a non-machining surface of a blade by using a six-point positioning method, wherein the points include a first positioning point A3 on a Y axis in a six-point positioning coordinate system, and the first positioning point A3 is located on a blade back section; an intermediate positioning point A3' is arranged on an extended section of a shroud sealing tooth of a blade crown, and the intermediate positioning point A3' and the other five points except the first positioning point A3 form six-point positioning points; in a detection and machining process, a six-point positioning gauge is used to detect whether the position of the first positioning point A3 is within a preset offset threshold range by using the intermediate positioning point A3', if yes, detection and machining are performed, otherwise, the position of the first positioning point A3 is re-determined; and the application avoids the problems of large detection error of a blade body profile and a blade passage surface, poor machining consistency and high machining scrap rate caused by large differences between positioning points.

Description

Technical Field

[0001] The invention belongs to the field of precision casting technology, specifically relating to a six-point positioning detection method for turbine blades. Background Technology

[0002] Turbine blades are complex, wide-ranging, stress-exposed, and load-bearing components in aero-engines and gas turbines. The geometry and size of the blade determine its performance, while the surface quality of the blade has a significant impact on the secondary flow loss of the engine, directly affecting its energy conversion efficiency. The positioning points of larger parts of the blade can be affected by the shrinkage of the wax mold during cooling, the shrinkage of the metal during the casting cooling process, and the displacement of the positioning points caused by the polishing of the blade surface. Therefore, the traditional six-point positioning detection of the blade surface will lead to inaccurate detection of the blade profile and blade flow channel surface dimensions, which will affect the performance of the turbine blade.

[0003] CN216731276U proposes a six-point positioning fixture for turbine blades, which allows the entire serrated surface to be ground on a grinding machine in a single clamping operation, improving the machining accuracy of the serrated surface. CN114043183A proposes a machining and verification method for turbine blades. CN114043183A proposes a six-point positioning gas turbine blade clamping gauge.

[0004] (CN203083481U) proposes a gas turbine blade clamping gauge based on six-point positioning. By ensuring consistency with the positioning datum of the blank manufacturer, it improves the pass rate of castings entering the factory and the pass rate of processing. The above patents all use traditional six-point positioning on the blade surface for positioning, which cannot solve the positioning point of the larger blade size. The positioning point will be offset due to the cooling shrinkage of the wax mold, the shrinkage of the metal during the casting cooling process, and the blade surface polishing. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a six-point positioning detection method for turbine blades, which can solve the problem of positioning point offset during blade processing and improve the positioning and processing accuracy of blades.

[0006] This invention is achieved through the following technical solution:

[0007] A method for six-point positioning and detection of turbine blades includes the following steps:

[0008] Six final positioning points are obtained on the unmachined surface of the blade using a six-point positioning method. The positioning points include a first positioning point A3 located on the Y-axis in the six-point positioning coordinate system. The first positioning point A3 is located on the blade back section.

[0009] An intermediate positioning point A3' is set on the extension of the leaf crown sealing tooth, and the intermediate positioning point A3' and the other five points excluding the first positioning point A3 constitute a six-point positioning point;

[0010] During the inspection and processing, a six-point positioning measuring tool is used to check whether the position of the first positioning point A3 is within the preset offset threshold range. If it is within the preset offset threshold range, inspection and processing are carried out; otherwise, the position of the first positioning point A3 is redefined.

[0011] Furthermore, the six final positioning points include two second positioning points A1 and a sixth positioning point A2 located on the root extension surface of the leaf back. The second positioning point A1 and the sixth positioning point A2 together with the first positioning point A3 determine the Y-axis of the leaf.

[0012] The six final positioning points also include a third positioning point B4 located on the side end face of the locking slot, and a fourth positioning point B5 located on the side of the blade crown sealing tooth. The third positioning point B4 and the fourth positioning point B5 together determine the blade X-axis.

[0013] The six final positioning points also include a fifth positioning point C6 located on the flow channel surface of the rim plate, which determines the blade's Z-axis.

[0014] Furthermore, the extension section of the leaf crown sealing tooth is provided with a U-shaped groove, and the intermediate positioning point A3' is located on the side of the U-shaped groove.

[0015] Furthermore, the thickness of the U-shaped groove is the same as the thickness of the crown sealing tooth, and the length of the U-shaped groove is 8-10mm and the height is 10-15mm.

[0016] Furthermore, the intermediate positioning point A3' is also located at the center of the central surface of the crown riser.

[0017] Furthermore, the contraction of the intermediate positioning point A3' in the Y-axis direction is minimized.

[0018] Furthermore, there are multiple crown sealing teeth, and the intermediate positioning point A3' is located on the crown sealing tooth in the middle position.

[0019] Furthermore, the dimensions of the turbine blade profile and flow channel surface are measured during the detection process.

[0020] Furthermore, during the detection process after fixing the turbine blades at the six positioning points, the offset threshold range is ±0.1mm.

[0021] Furthermore, during the processing, the blade blank is processed into a finished blade.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] This invention provides a six-point positioning detection method for turbine blades, comprising the following steps: obtaining six final positioning points on the unmachined surface of the blade using a six-point positioning method, wherein the positioning points include a first positioning point A3 located on the Y-axis in the six-point positioning coordinate system, the first positioning point A3 being located on the blade back section; setting an intermediate positioning point A3' on the extension section located on the crown sealing tooth, the intermediate positioning point A3' and the other five points excluding the first positioning point A3 forming a six-point positioning point; during the detection and machining process, using a six-point positioning gauge to detect whether the position of the first positioning point A3 is within a preset offset threshold range using the intermediate positioning point A3'; if it is within the preset offset threshold range, detection and machining are performed; otherwise, the position of the first positioning point A3 is redefined; this application employs a method with smaller shrinkage and more accurate dimensions. The position is used as the intermediate positioning point of the turbine blade. The final positioning point is checked to ensure that it is within the preset offset threshold range. Then, the dimensions of the blade profile and flow channel surface are checked using the final positioning point. This prevents the positioning point from being inaccurate due to subsequent grinding, and avoids the problems of large detection errors, poor machining consistency, and high machining scrap rate of turbine blade profile and flow channel surface caused by large differences in positioning points. In this application, the positioning point is selected at the center position in the Y-axis direction. This position is the part with the least contraction in this direction during the cooling of the wax mold and the cooling of the metal casting, which prevents the positioning inaccuracy caused by the cooling and contraction of the wax mold or molten metal. This method has been applied to the production of working blades of a two-stage hollow turbine of a gas turbine. The casting positioning is accurate, the turbine blade machining consistency is high, and the scrap rate is low. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the intermediate positioning point in the extension section of the leaf crown sealing tooth in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the U-shaped groove on the leaf crown sealing tooth in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the leaf-dorsal extension root in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the locking slot structure in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the edge plate flow channel in an embodiment of the present invention;

[0029] Figure 6 This is a top view of the blade in an embodiment of the present invention.

[0030] In the diagram: 1. Leaf crown sealing teeth; 2. Leaf back root extension; 3. Locking plate groove; 4. U-shaped groove; 5. Edge plate flow channel. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] This invention provides a six-point positioning detection method for turbine blades, comprising the following steps:

[0035] Six final positioning points are obtained on the unmachined surface of the blade using a six-point positioning method. The positioning points include a first positioning point A3 located on the Y-axis in the six-point positioning coordinate system. The first positioning point A3 is located on the blade back section.

[0036] An intermediate positioning point A3' is set on the extension of the crown sealing tooth 1, and the intermediate positioning point A3' and the other five points excluding the first positioning point A3 constitute a six-point positioning point;

[0037] During the inspection and processing, a six-point positioning measuring tool is used to check whether the position of the first positioning point A3 is within the preset offset threshold range. If it is within the preset offset threshold range, inspection and processing are carried out; otherwise, the position of the first positioning point A3 is redefined.

[0038] It should be noted that the six-point positioning method is existing technology. Its principle is that the workpiece has six degrees of freedom in space, namely, the translational degree of freedom along the three rectangular coordinate axes (x, y, z) and the rotational degree of freedom about these three coordinate axes. Therefore, to completely determine the position of the workpiece, these six degrees of freedom must be eliminated. Typically, six support point positioning elements are used to restrict the six degrees of freedom of the workpiece, with each support point restricting one corresponding degree of freedom.

[0039] It should be noted that the six-point positioning measuring tool is based on the six-point positioning method to measure the target positioning point, such as patent CN216745778. This content is prior art, and this application will not elaborate on it here.

[0040] Preferred, such as Figures 1-6 As shown, the six final positioning points include two second positioning points A1 and a sixth positioning point A2 located on the leaf back root 2 surface. The second positioning point A1 and the sixth positioning point A2 together with the first positioning point A3 determine the leaf Y-axis.

[0041] The six final positioning points also include a third positioning point B4 located on the side end face of the locking slot 3, and a fourth positioning point B5 located on the side of the blade crown sealing tooth 1. The third positioning point B4 and the fourth positioning point B5 together determine the blade X-axis.

[0042] The six final positioning points also include a fifth positioning point C6 located on the rim plate flow channel 5, which determines the blade Z-axis.

[0043] Preferably, the extension section of the leaf crown sealing tooth 1 is provided with a U-shaped groove 4, and the intermediate positioning point A3' is located on the side of the U-shaped groove 4.

[0044] Preferably, the thickness of the U-shaped groove 4 is the same as the thickness of the crown sealing tooth 1, and the length of the U-shaped groove 4 is 8-10mm and the height is 10-15mm.

[0045] Preferably, the intermediate positioning point A3' is located at the center of the central surface of the crown riser.

[0046] Preferably, the shrinkage of the intermediate positioning point A3' in the Y-axis direction is minimal. It should be noted that, in this embodiment, the minimal shrinkage in the Y-axis direction means that this position is the part with the least shrinkage in this direction during the cooling of the wax mold and the cooling of the metal pouring, thus preventing the positioning inaccuracy caused by the shrinkage of the wax mold or molten metal during cooling.

[0047] Preferably, there are multiple leaf crown sealing teeth 1, and the intermediate positioning point A3' is located on the leaf crown sealing tooth 1 at the middle position.

[0048] Preferably, the dimensions of the turbine blade profile and the flow channel surface are detected during the detection process.

[0049] Preferably, the offset threshold range during the detection process after fixing the turbine blades at the six positioning points is ±0.1mm.

[0050] Preferably, the blade blank is processed into a finished blade during the processing.

[0051] Example 1:

[0052] This embodiment takes the first-stage moving blade of a gas turbine turbine as an example. It is a directional columnar crystal blade, a type of...

[0053] The six-point positioning method for turbine blades is performed according to the following steps:

[0054] S1: Select six points (A1, A2, A3, B4, B5, C6) on the non-machined surface of the blade as the final positioning method for casting dimension inspection. Among them, positioning point A3 is on the blade back profile, and points A1 and A2 are at the blade back root. Points A1, A2, and A3 together determine the blade Y-axis.

[0055] S2: A notch is designed on the extension of the crown sealing tooth. One side of the notch is the center surface of the back of the basin. The thickness of the notch is the same as that of the crown sealing tooth, with a length of 10mm and a height of 15mm. All edges of the notch are rounded.

[0056] S3: Select a positioning point A3' at the center of the central surface of the crown riser described in step S2, where the contraction of point A3' in the Y-axis direction is minimal. Point A3' replaces the blade positioning point A3 that needs to be repaired in step S1, and together with the other five original positioning points (A1, A2, B1, B2, C6), forms a six-point positioning method. Detect the blade positioning point A3 to ensure that the fluctuation range of point A3 is controlled within the theoretical value ±0.10mm.

[0057] S4: After the blade positioning point A3 meets the requirements, the six-point positioning described in step S1 is used to detect the dimensions of the blade profile, flow channel surface, etc.

[0058] S5: Using the same positioning method, the blade blanks are processed to obtain the finished blades. The blade processing consistency is good and the scrap rate is low.

[0059] Example 2:

[0060] This embodiment uses the second-stage moving blade of a gas turbine as an example, which is an equiaxed crystal blade. A vortex...

[0061] The six-point positioning method for wheel blades is performed according to the following steps:

[0062] S1: Select six points (A1, A2, A3, B4, B5, C6) on the non-machined surface of the blade as the final positioning method for casting dimension inspection. Among them, positioning point A3 is on the blade back profile, and points A1 and A2 are at the blade back root. Points A1, A2, and A3 together determine the blade Y-axis.

[0063] S2: A notch is designed on the extension of the crown sealing tooth. One side of the notch is the center surface of the back of the basin. The thickness of the notch is the same as that of the crown sealing tooth, 10mm in length and 12mm in height. All edges of the notch are rounded.

[0064] S3: Select a positioning point A3' at the center of the central surface of the crown riser described in step S2, where the contraction of point A3' in the Y-axis direction is minimal. Point A3' replaces the blade positioning point A3 that needs to be repaired in step S1, and together with the other five original positioning points (A1, A2, B1, B2, C6), forms a six-point positioning method. Detect the blade positioning point A3 to ensure that the fluctuation range of point A3 is controlled within the theoretical value ±0.10mm.

[0065] S4: After the blade positioning point A3 meets the requirements, the six-point positioning described in step S1 is used to detect the dimensions of the blade profile, flow channel surface, etc.

[0066] S5: Using the same positioning method, process the blade blank to obtain the finished blade.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for six-point positioning and detection of turbine blades, characterized in that, Includes the following steps: Six final positioning points are obtained on the unmachined surface of the blade using a six-point positioning method. The positioning points include a first positioning point A3 located on the Y-axis in the six-point positioning coordinate system. The first positioning point A3 is located on the blade back section. An intermediate positioning point A3' is set on the extension of the leaf crown sealing tooth (1), and the intermediate positioning point A3' and the other five points excluding the first positioning point A3 constitute a six-point positioning point; During the inspection and processing, a six-point positioning measuring tool is used to check whether the position of the first positioning point A3 is within the preset offset threshold range. If it is within the preset offset threshold range, inspection and processing are performed; otherwise, the position of the first positioning point A3 is redefined. The six final positioning points include two second positioning points A1 and a sixth positioning point A2 located on the leaf back root (2) surface. The second positioning point A1 and the sixth positioning point A2 together with the first positioning point A3 determine the leaf Y-axis. The six final positioning points also include a third positioning point B4 located on the side end face of the locking slot (3) and a fourth positioning point B5 located on the side of the blade crown sealing tooth (1). The third positioning point B4 and the fourth positioning point B5 together determine the blade X-axis. The six final positioning points also include a fifth positioning point C6 located on the surface of the flange flow channel (5), which determines the blade Z-axis.

2. The six-point positioning and detection method for turbine blades according to claim 1, characterized in that, The extension section of the leaf crown sealing tooth (1) is provided with a U-shaped groove (4), and the intermediate positioning point A3' is located on the side of the U-shaped groove (4).

3. The six-point positioning and detection method for turbine blades according to claim 2, characterized in that, The thickness of the U-shaped groove (4) is the same as the thickness of the crown sealing tooth (1). The length of the U-shaped groove (4) is 8-10 mm and the height is 10-15 mm.

4. The six-point positioning and detection method for turbine blades according to claim 1, characterized in that, The intermediate positioning point A3' is also located at the center of the central surface of the crown riser.

5. The six-point positioning and detection method for turbine blades according to claim 1, characterized in that, The contraction of the intermediate positioning point A3' in the Y-axis direction is minimal.

6. The six-point positioning detection method for turbine blades according to claim 1, characterized in that, There are multiple leaf crown sealing teeth (1), and the intermediate positioning point A3' is located on the leaf crown sealing tooth (1) in the middle position.

7. The six-point positioning and detection method for turbine blades according to claim 1, characterized in that, The dimensions of the turbine blade profile and flow channel surface are measured during the testing process.

8. The six-point positioning and detection method for turbine blades according to claim 1, characterized in that, After the turbine blades are fixed at the positions of the six positioning points, the offset threshold range during the detection process is ±0.1mm.

9. The six-point positioning and detection method for turbine blades according to claim 1, characterized in that, During the processing, the blade blank is processed into a finished blade.

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