Method for measuring size of inner cavity of non-contact blade mold shell

Abstract

The invention discloses a non-contact blade mold shell inner cavity size measurement method, which comprises the following steps of pasting a reference point on the outer surface of a blade mold shell, and scanning the blade mold shell to obtain an outer surface model; breaking the blade mold shell to obtain a first shell and a second shell; s2, scanning a first shell to obtain a model A, and splicing the model A with the outer surface model of the blade mold shell in the step S1 according to a reference point to obtain a three-dimensional model C; scanning the second shell to obtain a model B, and splicing the model B and the three-dimensional model C according to the reference point to obtain a three-dimensional model D with a complete outer surface and a complete inner cavity surface; and processing the three-dimensional model D to obtain the size of the inner cavity of the blade mold shell. According to the method, the inner cavity of the blade mold shell is exposed, the inner cavity surface model and the outer surface model are obtained through scanning, the relative positions of the surfaces of the two half inner cavities are precisely restored through the reference points, the complete inner cavity model is obtained, and the precision of the calculated inner cavity size is high.

Description

Technical Field

[0001] The invention relates to the technical field of turbine blade precision casting, and in particular to a non-contact blade mold shell inner cavity dimension measurement method. Background Art

[0002] In order to achieve the expected engine performance of aircraft engines, the design department needs to put forward strict shape and position requirements for the outer dimensions of turbine blades. Precision casting is the mainstream process for producing aircraft engine turbine blades, and the main processes are mold making, shell making, pouring and post-processing. Molding is the process of injecting hot wax into a metal mold and opening the mold to obtain a wax model; shell making is the process of applying ceramic slurry and ceramic sand to the spliced ​​wax mold to form a cavity mold shell; pouring is the process of injecting molten metal into the mold shell cavity to obtain a casting. After the parameters or processes of these three processes are determined, a casting with a certain size can be obtained. Therefore, in order to ensure that the size of the casting meets the design requirements, it is necessary to accurately measure the size of the semi-finished products (wax mold shape, mold shell cavity and casting shape) in the process.

[0003] The turbine blade itself has a complex three-dimensional shape. The mold shell obtained by dewaxing cannot obtain the internal surface model because the light cannot reach it, making it difficult to measure the inner cavity size. At present, the following two methods are commonly used to measure the inner cavity size of turbine blades: one is to pour low-melting-point metal (such as tin-bismuth alloy), destroy the mold shell, and use three-coordinate or blue light scanning technology to measure the low-melting-point metal casting to obtain the inner cavity size of the mold shell. However, the low-melting-point metal itself undergoes a solidification and cooling process, and inevitably has shrinkage and elastic deformation, which is different from the actual inner cavity size of the mold shell; the second is to use CT technology to achieve non-destructive measurement of the inner cavity size of the mold shell, but the cost is relatively high.

[0004] At present, there are few methods for accurately measuring the inner dimensions of the mold shell, which cannot provide reliable data reference for quantitative analysis of the inner dimensions of the mold shell, increasing the cost of trial and error in the dimensions of high-temperature alloy precision castings. Therefore, it is urgent to propose a method for measuring the inner dimensions of the turbine blade mold shell. Summary of the invention

[0005] The present invention provides a non-contact blade mold shell inner cavity dimension measurement method to solve the technical problems of inaccurate mold shell inner cavity dimension measurement and high measurement cost in the prior art.

[0006] According to one aspect of the present invention, a non-contact blade mold shell inner cavity size measurement method is provided, the measurement method comprising the following steps:

[0007] Step S1: pasting reference points on the outer surface of the blade shell, and scanning the outer surface of the blade shell to obtain a blade shell outer surface model with all reference points;

[0008] Step S2: splitting the blade mold shell to expose the inner cavity of the blade mold shell, thereby obtaining a first shell and a second shell;

[0009] Step S3: Scan the first shell to obtain a model A having a first outer surface and a first inner cavity surface, and splice the model A with the outer surface model of the blade mold shell according to the reference point to obtain a three-dimensional model C having a complete outer surface, a first outer surface and a first inner cavity surface;

[0010] Step S4: Scan the second shell to obtain a model B having a second outer surface and a second inner cavity surface, and splice the model B with the three-dimensional model C according to the reference point to obtain a three-dimensional model D having a complete outer surface and a complete inner cavity surface;

[0011] Step S5: Process the three-dimensional model D to obtain the inner cavity size of the blade mold shell.

[0012] Furthermore, step S2 further includes cutting two grooves on the surface of the blade shell along the long axis direction of the blade shell;

[0013] Furthermore, the bottom of the groove is 1-2 mm away from the inner thickness of the blade shell.

[0014] Furthermore, cutting is performed along the inlet and outlet edges of the blade shell.

[0015] Furthermore, the scanning is a grating projection three-dimensional scanning, and the scanned blade shell model is obtained by using ATOS software.

[0016] Furthermore, in step S1, the surface of the blade shell is scanned multiple times, and the results of the multiple scans are spliced ​​using reference points, converted into the same coordinate system, and the mesh is refined to obtain a three-dimensional model of the blade shell.

[0017] Furthermore, in step S2, the number of reference points in the first shell and the second shell is no less than 6.

[0018] Furthermore, the blade mold shell is a blade mold shell.

[0019] Furthermore, in step S3, the blade shell outer surface model is used as a reference, a reference point common to model A and the blade shell outer surface model is selected, and model A is fitted to a position that matches the blade shell outer surface model.

[0020] Furthermore, in step S4, the three-dimensional model C is used as a reference, a reference point common to the model B and the three-dimensional model C is selected, and the model B is fitted to a position that matches the three-dimensional model C.

[0021] Furthermore, in step S5, the three-dimensional model D is processed using Geomagic software.

[0022] Furthermore, the method of processing the three-dimensional model D using Geomagic software includes the following contents:

[0023] Open the STL file of the blade shell theoretical model and the STL file of the three-dimensional model D with Geomagic software;

[0024] Select the outer surface model in Geomagic software and delete it to obtain a model with only the inner cavity.

[0025] The blade shell theoretical model is set as "reference", and the inner cavity model retained in the three-dimensional model D is set as "test". The two are compared to obtain the actual blade shell inner cavity size data.

[0026] The present invention has the following beneficial effects:

[0027] The present invention uses projection three-dimensional scanning technology to measure the inner cavity size of the blade mold shell. First, the outer surface of the blade mold shell is scanned to obtain an outer surface model of the blade mold shell with all reference points. Then, the blade mold shell is split open to obtain a first shell and a second shell, so that the inner cavity of the blade mold shell is exposed, so that the inner cavity model of the blade mold shell is obtained by using a blue light scanner; then the obtained first shell and second shell are scanned respectively, and the scanned models of the first shell and the second shell are spliced ​​with the outer surface model of the blade mold shell by pasting reference points on the outer surface of the mold shell, and the inner cavity surface models of the scanned models of the first shell and the second shell are accurately restored to the actual position inside the blade mold shell, thereby realizing accurate measurement of the inner cavity size of the mold shell.

[0028] The non-contact blade mold shell inner cavity size measurement method of the present invention overcomes the problem that the light cannot reach the blade mold shell inner cavity when using blue light scanning technology, thereby failing to obtain the blade mold shell inner cavity surface model, by breaking the blade mold shell apart to expose the blade mold shell inner cavity. At the same time, the reference point is used to accurately restore the relative positions of the two half inner cavity surfaces, so that the measurement result is not dependent on the operator's technique and proficiency. The technical process of the present invention is simple and fast, and the measurement accuracy is high.

[0029] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 It is a schematic diagram of the outer structure of the blade shell;

[0032] Figure 2 A schematic diagram of cutting a groove on the surface of a blade mold shell;

[0033] Figure 3 A schematic diagram of affixing an appropriate amount of reference points to the outer surface of the mold shell;

[0034] Figure 4 is a schematic diagram of the three-dimensional model C;

[0035] Figure 5 The schematic diagram of the model A after hiding the outer surface model of the three-dimensional model C;

[0036] Figure 6 Schematic diagram of the three-dimensional model D. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0038] The embodiment of the first aspect of the present invention provides a non-contact blade mold shell inner cavity size measurement method, the measurement method comprising the following steps:

[0039] Step S1: pasting reference points on the outer surface of the blade shell, and scanning the outer surface of the blade shell to obtain a blade shell outer surface model with all reference points;

[0040] Step S2: splitting the blade mold shell to expose the inner cavity of the blade mold shell, thereby obtaining a first shell and a second shell;

[0041] Step S3: Scan the first shell to obtain a model A having a first outer surface and a first inner cavity surface, and splice the model A with the outer surface model of the blade mold shell according to the reference point to obtain a three-dimensional model C having a complete outer surface, a first outer surface and a first inner cavity surface;

[0042] Step S4: Scan the second shell to obtain a model B having a second outer surface and a second inner cavity surface, and splice the model B with the three-dimensional model C according to the reference point to obtain a three-dimensional model D having a complete outer surface and a complete inner cavity surface;

[0043] Step S5: Process the three-dimensional model D to obtain the inner cavity size of the blade mold shell.

[0044] Grating projection 3D scanning technology is a mature technology that integrates optical, mechanical, electrical and computer technologies. It projects grating stripes onto the surface of an opaque, non-reflective object to obtain a 3D model of the object's surface. This technology is usually used to scan the shape of an object. For blade shells with complex inner cavities, the shape of the inner cavity cannot be obtained because of the problem that light cannot reach and focus. For general objects, the steps for 3D scanning to obtain the outer surface size of the object are as follows: 1. Spray powder (to make the object opaque); 2. Paste appropriate reference points on the surface of the object; 3. Use a blue light scanner to scan the surface of the object once or multiple times; 4. Use reference points to splice the results of multiple scans and convert them to the same coordinate system; 5. Refine the grid to obtain a 3D model of the object. 6. Use conventional software to process the 3D model to obtain the required outer surface size of the object.

[0045] In the present invention, for a blade shell with a complex inner cavity, a method for obtaining the inner cavity size using grating projection three-dimensional scanning technology is as follows:

[0046] Step S1 also includes: lightly grinding the outer surface of the blade mold to ensure that the outer surface is flat; using a cutting machine to cut two or more grooves on the surface of the blade mold along the long axis of the blade mold; pasting an appropriate amount of reference points on the flat outer surface of the blade mold, and the number of reference points is set according to actual needs; and using a blue light scanner to scan the outer surface of the blade mold, and obtain the outer surface model of the blade mold on the ATOS software, and all the reference points are on the outer surface model.

[0047] The described cutting machine is used to cut two or more grooves on the surface of the blade mold shell along the long axis direction of the blade mold shell, so that the blade mold shell can be broken in half along the long axis direction of the blade mold shell later to expose the inner cavity. If the grooves are cut along the short axis or radial direction of the blade mold shell, it may cause the light to still not fully illuminate all the inner cavity surfaces after the blade mold shell is broken. When cutting grooves on the surface of the blade mold shell, the surface of the blade mold shell cannot be cut through, otherwise there will be a problem of losing the inner cavity features. The reference point needs to be firmly pasted, and the reference point is pasted on a relatively flat position on the rough outer surface of the mold shell to avoid the subsequent splicing steps from being unable to be implemented due to the reference point falling or moving. During scanning, the measured blade mold shell is placed in the center of the automatic turntable, and the turntable is rotated several times, each time a certain angle is rotated to complete a rotation of the turntable. The camera will capture a frame of image every two rotations to record the appearance of the blade mold shell, and then automatically calculate through the software to obtain the sum of the blade mold shell surface that can be "seen" by the camera in each frame in the computer software ATOS. The scanning mentioned many times in the present invention is consistent with the scanning operation here.

[0048] In step S2, the blade mold shell is split apart along the cut groove to expose the inner cavity of the blade mold shell, thereby obtaining a first shell and a second shell shell; when the blade mold shell is cut, the blade mold shell is preferably cut in half to form a groove, so that the first shell shell and the second shell shell are symmetrical structures, and the inner cavity surface of the blade mold shell is fully exposed, so that the first shell shell and the second shell shell are 3D scanned by projection 3D scanning technology to obtain a 3D model of the first shell shell and the second shell shell with an inner cavity model and an outer surface model;

[0049] In step S3, the first shell is scanned separately to obtain a model A having a first outer surface (with half of the reference points) and a first inner cavity surface, and the model A is spliced ​​with the blade mold shell outer surface model obtained in step 1 according to the reference points pasted on the outer surface to obtain a three-dimensional model C having a complete outer surface, a first outer surface and a first inner cavity surface. When scanning the first shell, since the inner cavity of the blade mold shell is exposed, there is no surface that cannot be scanned because the light cannot reach it.

[0050] In step S4, the second shell is scanned separately to obtain a model B having a second outer surface (with the other half of the reference points) and a second inner cavity surface, and the model B is spliced ​​with the three-dimensional model C in step S3 according to the reference points pasted on the outer surface to obtain a three-dimensional model D with a complete outer surface and a complete inner cavity surface. The splicing of model A with the outer surface model of the blade mold shell in step S3 and the splicing of model B with the three-dimensional model C in step S3 in step S4 are routine operations of the blue light model processing software, which need to use the mold shell shape scanned for the first time as a reference, select the reference points (no less than 6) shared by each mold shell and the mold shell shape, and fit the inner cavity of each mold shell to a position that matches the shape.

[0051] In step S5, the three-dimensional model D is processed using conventional software Geomagic to obtain the inner cavity size of the blade mold shell.

[0052] The present invention uses projection three-dimensional scanning technology to measure the inner cavity size of the blade mold shell. First, the outer surface of the blade mold shell is scanned to obtain a blade mold shell outer surface model with all reference points. Then, the blade mold shell is split apart along the cutting line on the blade mold shell surface to obtain a first shell and a second shell, so that the inner cavity of the blade mold shell is exposed, which is convenient for obtaining the blade mold shell inner cavity model by blue light scanning; the first shell shell and the second shell shell are scanned respectively, and the scanned models of the first shell shell and the second shell shell are spliced ​​with the blade mold shell outer surface model by pasting reference points on the outer surface of the mold shell, and the inner cavity surface model of the scanned models of the first shell shell and the second shell shell is accurately restored to the actual position inside the blade mold shell, thereby realizing accurate measurement of the mold shell inner cavity size.

[0053] The non-contact method for measuring the inner cavity size of a blade mold shell of the present invention overcomes the problem that the light cannot reach the inner cavity of the blade mold shell when using the blue light scanning technology, thus making it impossible to obtain the surface model of the inner cavity of the blade mold shell, by splitting the blade mold shell to expose the inner cavity of the blade mold shell. At the same time, the relative positions of the two half inner cavity surfaces are accurately restored by using reference points, so that the measurement result does not depend on the operator's technique and proficiency. The technical process of the present invention is simple and fast, and the measurement accuracy is high.

[0054] In an embodiment of the present invention, the scanning is raster projection three-dimensional scanning, and the scanned blade mold shell model is obtained by using ATOS software. The present invention uses a three-dimensional blue light scanner to scan the blade mold shell and uses ATOS software to process the obtained scanned blade mold shell model.

[0055] In an embodiment of the present invention, in step S1, the surface of the blade mold shell is scanned multiple times, and the results of the multiple scans are stitched using reference points, converted into the same coordinate system, and the grid is refined to obtain the three-dimensional model of the blade mold shell. During the scanning process, the blade mold shell to be measured is placed in the center of the automatic turntable. The turntable rotates in several times, each time rotating a certain angle to complete one full rotation of the turntable. A frame of image is captured by the camera at the interval between every two rotations to record the appearance shape of the blade mold shell. Then, through automatic calculation by the software, the sum of the surface of the blade mold shell that can be "seen" by each captured shot is obtained in the computer software ATOS. The results of the multiple scans are stitched using reference points, converted into the same coordinate system, and the grid is refined to obtain the three-dimensional model of the blade mold shell.

[0056] In an embodiment of the present invention, the number of reference points in the first shell and the second shell in step S2 is not less than 6. The number of reference points in the first shell and the second shell in the present invention is more than 6. When pasting reference points on the surface of the blade mold shell, the positions of the reference points can be determined according to the 6-point positioning principle, which is convenient for making the positioning of the model more accurate during subsequent model stitching.

[0057] In an embodiment of the present invention, in step S1, it also includes cutting the blade mold shell from the blade module using a cutting machine to ensure the integrity of the blade mold shell; cutting two grooves on the surface of the blade mold shell along the long axis direction of the blade mold shell, and the distance from the bottom of the groove to the inner cavity thickness of the blade mold shell is 1-2 mm. The blade mold shell has a complex three-dimensional shape. Since the light cannot reach the inside, it is impossible to obtain the internal surface model, making it difficult to measure the inner cavity size. The blade mold shell is usually an integral structure and has a complex inner cavity. The present invention cuts two grooves on the surface of the blade mold shell along the long axis direction of the blade mold shell, which is beneficial for scanning the outer surface of the blade mold shell and then splitting the blade mold shell along the grooves to expose the inner cavity, facilitating the scanning of the inner cavity of the blade mold shell to obtain a complete inner cavity model.

[0058] The number of the grooves is preferably two, and they are preferably symmetrically arranged so that the blade mold shell can be split in half, and the inner cavity of the blade mold shell is fully exposed, avoiding the situation where the blue light cannot be scanned. If only one groove is cut on the surface of the blade mold shell, it is not conducive to splitting the mold shell, and there is a situation where the blue light cannot be scanned. The present invention can also cut more than two grooves on the surface of the blade mold shell according to actual conditions to divide the blade mold shell into multiple parts. The bottom of the cut groove needs to be 1-2mm away from the inner cavity of the mold shell for the following reasons: on the one hand, it can avoid the problem that the crack does not crack along the inlet and exhaust edges when the mold shell is split in step S2 due to the large distance, thereby affecting the integrity of the inner cavity scan; on the other hand, it also reduces the phenomenon of losing the inner cavity characteristics of the mold shell due to directly cutting through the mold shell.

[0059] In an embodiment of the present invention, cutting is performed along the inlet and outlet edges of the blade mold shell. Using a cutting machine to cut along the inlet and outlet edges of the blade mold shell in the long axis direction of the blade mold shell can ensure that as many mold shell inner cavity model features as possible are obtained in each scan. If the mold shell is not cut along the inlet and outlet edges, when the mold shell inner cavity is scanned, only a small number of mold shell inner cavity model features can be obtained due to the straight-line irradiation of the light.

[0060] In the embodiment of the present invention, in step S3, the blade mold shell outer surface model scanned and obtained in step S1 is used as a reference, the reference points common to the model A corresponding to the first shell (with half of the reference points) and the blade mold shell outer surface model are selected, and the model A is fitted to a position that matches the blade mold shell outer surface model to obtain a three-dimensional model C. Through this step, the first inner cavity surface model of the first mold shell can be obtained.

[0061] In the embodiment of the present invention, in step S4, the three-dimensional model C is used as a reference, the reference points common to the model B corresponding to the second shell (with the other half of the reference points) and the three-dimensional model C are selected, and the model B is fitted to a position that matches the three-dimensional model C to obtain the three-dimensional model D. Through this step, the second inner cavity surface model of the second mold shell is obtained, and the second inner cavity surface model is spliced ​​with the first inner cavity surface model, so that the complete inner cavity surface model of the blade mold shell can be obtained.

[0062] In the embodiment of the present invention, in step S5, the three-dimensional model D is processed using Geomagic software.

[0063] The method for processing the three-dimensional model D using Geomagic software comprises the following steps:

[0064] The STL file of the blade shell theoretical model and the STL file of the three-dimensional model D (with the shell cavity and shell shape) finally obtained by blue-ray scanning are opened with Geomagic software;

[0065] Select the part of the mold shell shape in the software and delete it to obtain a model with only the inner cavity shape (model denoising);

[0066] Set the blade shell theoretical model to "reference" and the shell inner cavity model to "test", compare the two, and obtain the actual shell inner cavity size data.

[0067] The following examples describe the present disclosure in more detail, and these examples are intended for illustrative purposes only.

[0068] Example 1

[0069] This embodiment provides a non-contact mold shell inner cavity size measurement method, comprising the following steps:

[0070] Step 1: Use a cutting machine to cut the blade mold from the mold set to ensure that the blade mold is complete. Figure 1 ;

[0071] Step 2: Slightly grind the outer surface of the blade shell to ensure that the outer surface is flat; the flat surface formed by cutting the shell from the module is used here;

[0072] Step 3: Use a cutting machine to cut two grooves on the surface of the blade mold along the long axis of the blade mold, along the inlet and outlet edges of the blade, with the bottom of the groove 1-2mm away from the thickness of the mold cavity; see Figure 2 ;

[0073] Step 4: Paste appropriate reference points on the flat outer surface of the mold shell, see Figure 3 , the reference points are pasted on both sides of the blade mold shell; and a blue light scanner is used to scan the outer surface of the mold shell, and the outer surface model of the blade mold shell is obtained on the ATOS software. The outer surface model has all the reference points.

[0074] Step 5: Split the blade mold shell along the two grooves, and scan the first mold shell. The obtained model A consists of half of the outer surface (with half of the reference points) and half of the inner surface;

[0075] Step 6: Using the reference points attached to the outer surface of the mold shell, join the model A obtained in step 5 with the outer surface model of the blade mold shell obtained in step 4 to obtain a three-dimensional model C with a complete outer surface, half of the outer surface, and half of the inner surface; see Figure 4 , Figure 4 The middle gray part is the outer surface model of the blade mold shell, and the red part is model A. After splicing model A with the outer surface model of the blade mold shell, the outer surface model of the blade mold shell is hidden, and only model A is displayed. Figure 5 shown.

[0076] Step 7: Scan the second mold shell, and the obtained model B consists of half of the outer surface (with half of the reference points) and the other half of the inner surface;

[0077] Step 8: Use the reference points attached to the outer surface of the mold shell to splice the model B obtained in step 7 and the three-dimensional model C obtained in step 6 to obtain a three-dimensional model D with a complete outer surface and a complete inner cavity surface. Figure 6 .

[0078] Step 9: Open the STL file of the blade shell theoretical model and the STL file of the 3D model D (with the shell inner cavity and shell shape) finally obtained by blue-ray scanning with Geomagic software;

[0079] Select the part of the mold shell shape in the software and delete it to obtain a model with only the inner cavity shape (model denoising);

[0080] Set the blade shell theoretical model to "reference" and the shell inner cavity model to "test", compare the two, and obtain the actual shell inner cavity size data.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A non-contact blade mold shell inner cavity size measurement method, characterized in that: The measuring method comprises the following steps: Step S1: pasting reference points on the outer surface of the blade shell, and scanning the outer surface of the blade shell to obtain a blade shell outer surface model with all reference points; Step S2: splitting the blade mold shell to expose the inner cavity of the blade mold shell, thereby obtaining a first shell and a second shell; Step S3: Scan the first shell to obtain a model A having a first outer surface and a first inner cavity surface, and splice the model A with the blade mold shell outer surface model in step S1 according to the reference point to obtain a three-dimensional model C having a complete outer surface, a first outer surface and a first inner cavity surface; Step S4: Scan the second shell to obtain a model B having a second outer surface and a second inner cavity surface, and splice the model B with the three-dimensional model C according to the reference point to obtain a three-dimensional model D having a complete outer surface and a complete inner cavity surface; Step S5: Process the three-dimensional model D to obtain the inner cavity size of the blade mold shell.

2. The non-contact blade mold cavity size measurement method according to claim 1 is characterized in that: Step S1 also includes cutting two grooves on the surface of the blade shell along the long axis direction of the blade shell.

3. The non-contact blade mold cavity size measurement method according to claim 2 is characterized in that: The bottom of the groove is 1-2 mm away from the inner cavity thickness of the blade mold shell.

4. The non-contact blade mold cavity size measurement method according to claim 2 is characterized in that: Grooves are formed by cutting along the inlet and outlet edges of the blade shell.

5. The non-contact blade mold shell inner cavity dimension measurement method according to claim 1, characterized in that: In step S1, the surface of the blade shell is scanned multiple times, and the results of the multiple scans are spliced ​​using reference points and converted into the same coordinate system to obtain a three-dimensional model of the blade shell.

6. The non-contact blade mold shell inner cavity dimension measurement method according to claim 1, characterized in that: In step S2, the number of reference points in the first shell and the second shell is no less than 6.

7. The non-contact blade mold shell inner cavity dimension measurement method according to claim 1, characterized in that: In step S3, the blade shell outer surface model is used as a reference, a reference point common to model A and the blade shell outer surface model is selected, and model A is fitted to a position that matches the blade shell outer surface model.

8. The non-contact blade mold shell inner cavity dimension measurement method according to claim 1, characterized in that: In step S4 , the three-dimensional model C is used as a reference, a reference point common to the model B and the three-dimensional model C is selected, and the model B is fitted to a position that matches the three-dimensional model C.

9. The non-contact blade mold cavity dimension measurement method according to claim 1, characterized in that: In step S5, the three-dimensional model D is processed using Geomagic software.

10. The non-contact blade mold shell inner cavity dimension measurement method according to claim 9, characterized in that: The method of processing the three-dimensional model D using Geomagic software includes the following: Open the STL file of the blade shell theoretical model and the STL file of the three-dimensional model D with Geomagic software; Select the outer surface model in Geomagic software and delete it to obtain a model with only the inner cavity. The blade shell theoretical model is set as "reference", and the inner cavity model retained in the three-dimensional model D is set as "test". The two are compared to obtain the actual blade shell inner cavity size data.

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