A test specimen, a fixture and a method of testing a three-segment roller profile

Abstract

The application discloses a test sample, a clamp and a test method of a three-section roller profile, the test sample comprises a test processing area and a thickened bottom, and the connection between the bottom and the processing area is an arc-shaped connection. The clamp comprises a bottom plate, a pair of side positioning blocks arranged on the upper end surface of the bottom plate, and an angular positioning block arranged on the side surface of the bottom plate. The test method comprises the following steps: clamping the test sample by using a special tool, testing and processing after the profile of a diamond roller is modified, performing three-section scanning profile by using a three-coordinate after the test and processing are completed, importing profile data into CAD to produce a roller profile, and completing profile data analysis by using a profile analysis method. The application improves the determination accuracy of the profile size consistency of the roller after manufacturing, provides a more accurate determination method for the result determination of the profile, and provides theoretical data support for the manufacturing and acceptance of the roller.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine blade technology, specifically relating to a test specimen, fixture, and test method for a three-section roller profile. Background Technology

[0002] Aero-engine blades are mainly divided into stationary blades and moving blades. Moving blades are generally connected to disc-shaped parts via tenons. The blade tenons are high-precision machines with small profile requirements and strict tolerances, and are mostly machined using creep-feed grinding. Creep-feed grinding is a process of forming male and female molds by dressing the grinding wheel profile with rollers, so the manufacturing precision and profile conformity requirements of the rollers are extremely high.

[0003] In traditional roller profile machining and testing, graphite or stainless steel test pieces are often used, typically around 1mm thick. While graphite test pieces are less prone to deformation, they are difficult to machine and easily break or fracture during processing, making the design of the clamping method challenging. Stainless steel test pieces, due to insufficient rigidity, are more likely to deform before and after machining, and the risk of deformation is even higher during long-term storage. This leads to inaccurate test results, substandard rollers, and failure to pass acceptance testing. Summary of the Invention

[0004] To address the aforementioned problems, this invention aims to provide a testing method for a test specimen, a fixture, and a three-section roller profile.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a test specimen, including a test processing area and a thickened bottom, wherein the connection between the bottom and the processing area is an arc-shaped connection.

[0006] Preferably, the test piece is subjected to stress relief treatment using a heat treatment regime of HRC35-40.

[0007] Preferably, the thickness of the processed area of ​​the test piece is 20 mm, the thickness of the bottom is 40 mm, and the reference surface is treated with surface finish.

[0008] A test fixture includes a base plate, a pair of side positioning blocks disposed on the upper surface of the base plate, and angular positioning blocks disposed on the side of the base plate.

[0009] Preferably, the lateral positioning block is "L" shaped, and the upper end of the lateral positioning block is divided into a clamping support. A clamping screw hole is provided on the side of the clamping support, and a clamping bolt is provided to cooperate with the clamping screw hole to fix the test piece. There is a clamping space between the two lateral positioning blocks, and the angular positioning block is fixed to the side of the base plate corresponding to the clamping space by screws.

[0010] Preferably, the surface roughness of the clamping space is greater than or equal to 1.60, which is consistent with the surface roughness of the test piece, and the fixture is made of 45# steel that has been quenched.

[0011] A three-segment roller profile testing method includes the following steps: Step 1: Install the test fixture on the feed device, align the fixture in the X and Y directions, and fix the fixture. Step 2: Install the test piece on the clamp and tighten the clamping bolts to secure the test piece; Step 3: Adjust the machining process parameters and use a roller to dress the grinding wheel. The dressing depth is greater than the maximum contour X of the roller. On the machine tool, use the dressed grinding wheel to perform roughing, semi-finishing, and finishing multi-tool machining on the test piece to simulate the actual machining state of the part and complete the contour machining. Step 4: Use a coordinate measuring machine to perform a three-segment scan on one interface on the left and right sides of the test piece and another interface within the middle of the test piece. The scan results will provide feedback on the contour deviation caused by the instability of the grinding process. Step 5: Compare the scanning results obtained in Step 4 with the contour tolerance zone required by the process. If each contour segment meets the tolerance zone requirements, then the contour of the roller during manufacturing conforms to the process drawing requirements.

[0012] Preferably, in step 3, the processing parameters are adjusted to be consistent with the actual processing parameters of the roller, and the roller is made of diamond.

[0013] Preferably, the three-segment scanning position in step 4 also includes arbitrarily selecting three interfaces for contour scanning, and the three-segment contour can also be a multi-segment contour.

[0014] Preferably, the R-dimensional dimension at the contour transition point of the test piece is determined by drawing a circle at three points.

[0015] Compared with existing technologies, this invention has the following advantages: This invention uses a 20mm thick stainless steel test piece with a heat treatment process of HRC35~40, and employs a dedicated clamping fixture. The three-segment or multi-segment contour judgment and transition radius judgment methods improve the accuracy of determining the conformity of the roller's post-manufacturing contour dimensions, providing a more precise method for contour determination and offering theoretical data support for roller manufacturing and acceptance. Furthermore, this invention thickens the deformable end of the test piece, reducing the risk of deformation over long periods. Once the provided test piece passes inspection, it can be used with confidence, reducing repeated testing and lowering the product scrap rate. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a three-dimensional view of the test specimen in this invention; Figure 2 This is a side view of the test specimen in this invention; Figure 3 This is a top view of the test specimen in this invention; Figure 4 This is a three-dimensional schematic diagram of the test fixture in this invention; Figure 5 This is a schematic diagram of the sample clamping in this invention; Figure 6 This is a diagram illustrating the process of roller dressing the grinding wheel and grinding wheel machining test piece in this invention; Figure 7 This is a 30x magnified comparison image of the three contours in this invention; Figure 8 for Figure 7 Enlarged view of point A; Figure 9 This is a schematic diagram of the determination of the adapter R in this invention; In the diagram, 1-lateral positioning block; 2-base plate; 3-clamping support; 4-angular positioning block; 5-roller; 6-grinding wheel. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0019] The test piece, fixture, and testing method of this invention are designed for machining complex surface profiles such as blade tenons and blade crowns using creep-feed grinding, providing a stable and long-term testing method for the manufacture and inspection of rollers with complex blade profiles. By designing a more rigid and easier-to-store test piece, fixture, and a three-segment roller profile determination method, more accurate diamond roller profile data is provided.

[0020] Reference Figures 1-3A test specimen is proposed, comprising a test processing area and a thickened bottom, with an arc-shaped connection between the bottom and the processing area. The design of the specimen aims to ensure both high rigidity and strength while also considering manufacturing economy. A 20mm thick test processing area was ultimately chosen, with a 40mm thickened design within the bottom 20mm range. After processing, the specimen undergoes stress relief treatment according to an HRC35-40 heat treatment regime. The advantages of this design are: firstly, it guarantees the rigidity of the specimen at a technical level, significantly exceeding that of 1mm thick stainless steel and graphite specimens; secondly, it offers superior toughness and wear resistance. Furthermore, the surface finish of the reference surface is treated to meet the requirements of aero-engine blade positioning surfaces, ensuring the surface finish of the specimen's clamping surface and further guaranteeing clamping consistency during processing and testing.

[0021] Reference Figures 4-5 The test fixture consists of a 45# steel base plate 2, side positioning blocks 1, angular positioning blocks 4, clamping supports 3, and 6 positioning screws and 1 clamping bolt. The side positioning blocks 1 are L-shaped, with the upper end divided into clamping supports 3. Clamping screw holes are provided on the side of the clamping supports 3, and clamping bolts are installed to engage with these holes to secure the test piece. A clamping space is provided between the two side positioning blocks 1, which are fixed to the upper surface of the base plate 2 by positioning screws. The angular positioning block 4 is fixed to the corresponding side end of the base plate 2 by screws. The positioning surfaces of the fixture maintain the same surface finish as the test piece, meeting the requirement of a surface roughness of 1.60 according to the positioning reference surface requirements for aero-engine blades, ensuring compatibility between the test piece and the fixture. The fixture is ingeniously designed, with overall dimensions of 120mm × 60mm, and is easy to use; during use, the test piece can be secured simply by tightening the clamping bolt through the clamping screw holes.

[0022] The verification process is as follows: 1) Install the test fixture on the feed device, align the fixture in the X and Y directions, and fix the fixture; 2) Install the test piece onto the clamp and tighten it; 3) Adjust the machining process parameters to be consistent with the actual machining parameters of the part, and then use roller 5 to complete the initial dressing of grinding wheel 6. The dressing depth should be greater than the maximum contour X of the roller to ensure that the machining contour is completely dressed. Figure 4 As shown; after the tool setting of the test piece is completed on the machine tool, the machining is divided into roughing, semi-finishing and finishing multi-tool machining through program adjustment to simulate the actual machining state of the part and complete the contour machining; before finishing, roller 5 is used to complete the finishing before finishing, with a correction amount of 2 to 5 mm to ensure the accuracy of the roller contour before finishing. 4) Reference Figures 6-8Using a coordinate measuring machine, a three-section scan is performed on one interface within a 3-5mm range on the left and right sides of the test piece, and another interface within a 2mm range in the middle of the test piece. Alternatively, any three interfaces can be selected for contour scanning. The contour data is then imported into CAD to produce the roller contour, and contour data analysis is performed using surface contour analysis methods. Three-section or multi-section contour scanning can provide actual feedback on contour deviations caused by instability in the grinding process, further confirming the accuracy of the roller contour and the consistency of contours between different sections. 5) Compare the scanning results obtained in step 4 with the contour tolerance zone required by the process. If each contour segment meets the tolerance zone requirements, then the contour of the roller meets the requirements of the process drawing during manufacturing.

[0023] In this experiment, three contour points—5mm, 25mm, and 45mm—were scanned to obtain the actual contour. These contours were then compared with the required tolerance zones specified in the manufacturing process. All contour segments met the tolerance zone requirements, thus confirming that the roller's contour conformed to the process drawings during manufacturing. (Refer to...) Figure 9 For the adapter R dimension, the radius of the adapter R can be determined by drawing a circle at three points, provided that the tolerance zone requirements are met.

[0024] This invention involves testing by increasing the thickness of the test piece from 2mm to 20mm. The formed contour is generally not less than 30mm. Using a 2mm thick contour test piece increases the risk of inconsistent repeated measurements during later storage. After receiving the roller, it may be used for an extended period, and testing after this time will reveal deviations in dimensional stability. Directly using this roller for processing risks product scrapping and increases acceptance costs. The advantage of using a test piece of this thickness is that, after thickening and heat treatment, the rigidity is more stable, and a stable 20mm contour can be produced. Through three-segment contour comparison analysis, the accuracy of the contour can be more accurately determined, providing a more accurate judgment method for roller manufacturing, testing, and retesting.

[0025] The present invention has provided a detailed description of a test specimen, fixture, and test method for a three-section roller profile. Specific examples have been used to illustrate the structure and working principle of the invention. The descriptions of the embodiments are merely for the purpose of helping to understand the method and core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A three-segment roller profile testing method, characterized in that: Auxiliary tests were conducted using test pieces and fixtures. The test piece included a test processing area and a thickened bottom. The thickness of the processing area of ​​the test piece was 20 mm, and the thickness of the bottom was 40 mm. The reference surface was treated with a smooth finish. The connection between the bottom and the processing area was an arc-shaped connection. The test piece was subjected to stress relief treatment using a heat treatment regime of HRC35~40. The fixture includes a base plate (2), a pair of side positioning blocks (1) set on the upper end face of the base plate (2), and angular positioning blocks (4) set on the side of the base plate (2). A clamping space is left between the two side positioning blocks (1). The surface roughness of the clamping space is greater than or equal to 1.60, which is consistent with the surface roughness of the test piece. The fixture is made of 45# steel quenched. Test methods Includes the following steps, Step 1: Install the test fixture on the feed device, align the fixture in the X and Y directions, and fix the fixture. Step 2: Install the test piece on the clamp and tighten the clamping bolts to secure the test piece; Step 3: Adjust the processing parameters and use the roller (5) to dress the grinding wheel (6). The dressing depth is greater than the maximum contour X of the roller (5). On the machine tool, use the dressed grinding wheel (6) to perform roughing, semi-finishing, and finishing multi-tool processing on the test piece to simulate the actual processing state of the part and complete the contour processing. Step 4: Use a coordinate measuring machine to perform a three-segment scan on one interface on the left and right sides of the test piece and another interface within the middle of the test piece. The scan results will provide feedback on the contour deviation caused by the instability of the grinding process. Step 5: Compare the scanning results obtained in Step 4 with the contour tolerance zone required by the process. If each contour segment meets the tolerance zone requirements, then the contour of the roller during manufacturing conforms to the process drawing requirements.

2. The three-segment roller profile test method according to claim 1, characterized in that: In step 3, the processing parameters are adjusted to be consistent with the actual processing parameters of the roller, and the roller is made of diamond.

3. The three-segment roller profile test method according to claim 1, characterized in that: The three-segment scanning position in step 4 also includes arbitrarily selecting three interfaces for contour scanning, and the three-segment contour can also be a multi-segment contour.

4. The three-segment roller profile test method according to claim 1, characterized in that: The radius (R) at the contour transition of the test piece is determined by drawing a circle at three points.

5. The three-segment roller profile test method according to claim 1, characterized in that: The lateral positioning block (1) is "L" shaped. The upper end of the lateral positioning block (1) is divided into a clamping support (3). A clamping screw hole is provided on the side of the clamping support (3), and a clamping bolt is provided to cooperate with the clamping screw hole to fix the test piece. The angular positioning block (4) is fixed to the side of the base plate (2) corresponding to the clamping space by screws.

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