Blisk airfoil milling deformation adjustment method

Abstract

A blisk airfoil milling deformation adjustment method relates to the technical field of blisk processing and comprises the following steps: S1: design coordinate points of each section of the airfoil into editable text format, and generate a spline curve through points; S2: use a three-coordinate measuring machine to process and detect a test piece; S3: import measured points into software; S4: coincide a theoretical section with a measured section; S5: respectively establish airfoil, back, inlet edge and exhaust edge surfaces of the compensated curve through a curve grid command, and stitch the surfaces to establish a compensation model; S6: detect all sections; and S7: select an exhaust edge profile coincident section, and perform blade polishing and improvement. The method solves the problem that in the traditional adjustment method, due to large deformation differences at different positions of the airfoil, the connection is discontinuous during the reconstruction of the overall model, the surface reconstruction is difficult, the reconstruction efficiency is low, and batch production is difficult.

Description

Technical Field

[0001] This invention relates to the field of integral bladed disk machining technology, and specifically to a method for adjusting the milling deformation of the blade profile of an integral bladed disk. Background Technology

[0002] The blade profile of an aero-engine integral bladed disk (IBD) is characterized by thin walls, large spatial twist, and long cantilever. To improve strength and reduce engine weight, IBDs often use titanium alloys and aerospace-grade aluminum alloys as component materials. However, these materials have poor cold working properties, resulting in severe machining deformation. After machining, the blade profile, twist angle, and positional tolerances may fail to meet design requirements. To reduce deformation, processing methods are typically considered, such as split rough and finish milling with stress-relieving heat treatment to eliminate internal stress during machining. Sharp cutting tools are selected, and the smallest possible tool radius is chosen to reduce cutting forces. Symmetrical helical milling and appropriate cutting parameters are employed. These processing methods can reduce machining deformation, but errors relative to the machined model still exist.

[0003] As existing methods are used, their shortcomings have gradually become apparent, mainly in the following aspects: First, existing adjustment methods, when used, result in discontinuities at the joints during overall model reconstruction due to significant differences in deformation at different locations of the blade shape. This leads to difficulties in surface reconstruction, low reconstruction efficiency, and difficulty in mass production.

[0004] Secondly, existing technologies require separate processing of the inlet and outlet sides of the blades, which is time-consuming and greatly reduces the overall processing efficiency.

[0005] In conclusion, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention solves the problems of traditional adjustment methods, which, due to the significant differences in deformation at different locations of the blade, result in discontinuities at the joints during overall model reconstruction, leading to difficulties in surface reconstruction, low reconstruction efficiency, and difficulty in mass production; and the time-consuming process of separately machining the inlet and exhaust edges of the blade, which greatly reduces the overall processing efficiency.

[0007] To address the above problems, the present invention provides the following technical solution: A method for adjusting the milling deformation of an integral bladed disk blade profile includes the following steps: S1: Create the design coordinate points of each section of the blade profile into an editable text format, generate spline curves from the points, establish the theoretical curves of the section profile from the spline curves, and establish the blade profile surface from the theoretical curves of the section profile. S2: Use a coordinate measuring machine to process and inspect the test piece, and output the measured points for each cross section; S3: Import the measured points into the software, and establish spline curves by segmenting the measured values ​​according to the curvature changes. Draw the measured cross section based on the spline curves. S4: Overlap the theoretical section with the measured section, and draw the compensation section by reverse compensation of the motion of the theoretical section and the measured section overlapping; S5: Use the curve mesh command to create the compensated blade basin, blade back, air intake edge, and exhaust edge surfaces respectively, and stitch the surfaces together to create the compensation model. S6: Check all sections to see if they meet the design requirements; if they do not meet the design requirements, repeat S3-S5 to iteratively compensate the existing model. S7: Select the overlapping section of the intake and exhaust edge contours and polish the blades; compare the intake and exhaust edges of different cross-section blade types in the two sections of the blade basin and blade back; design corresponding machining tools for the overlapping section and use the variable axis machining method to machine the intake and exhaust edge contours in one piece.

[0008] Furthermore, in S1, the design coordinate points of each section of the blade are made into DAT editable text format, and the command to generate splines from points is used in the software.

[0009] Furthermore, in S1, theoretical curves for each cross section are established using spline curves, and leaf-shaped surfaces are created from the theoretical curves of each cross section using the curve mesh command.

[0010] Furthermore, the coordinate measuring machine in S2 outputs a DAT file of the measured points, and the output measured points are in a non-fit state; the coordinate measuring machine can automatically divide the points according to the curvature change, and the division method is the chord tolerance method.

[0011] Furthermore, the segmentation principle in S3 is to divide the area into the intake side, exhaust side, blade basin, and blade back according to the curvature change of the measured points; the intake side and exhaust side have a higher density of sampling points than the blade basin and blade back areas.

[0012] Furthermore, in S3, the measured points in the divided areas are used to draw spline curves using the curve-artistic spline command to draw four curve segments: the intake side, the exhaust side, the blade base, and the blade back, forming the measured cross section.

[0013] Furthermore, in the software, S4 uses an alignment command to individually move the four curves of the measured cross-section—inlet side, exhaust side, blade base, and blade back—to the theoretical cross-section, translating and offsetting them to the optimal position.

[0014] Furthermore, the S4 replicates the theoretical cross-sectional curve and, through curvature changes, also divides it into four curves: the intake side, exhaust side, blade basin, and blade back. The replicated theoretical cross-sectional curves are then shifted in the same reverse direction as the aforementioned shift parameters to obtain the compensated cross-sectional curves.

[0015] Furthermore, S4 connects the moved curves and forms a complete closed-loop section curve using the bridging curve command in the software. Then, all sections of the blade are processed in the same way.

[0016] Furthermore, in step S5, the blade base, blade back, air intake edge, and exhaust edge curved surfaces are stitched together to create a compensated blade model.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Reverse compensation can improve machining accuracy and product qualification rate, and solve the problems of blade profile, torsion angle and positional deviation caused by deformation.

[0018] Each section of the blade base, blade back, air intake edge, and air exhaust edge is adjusted separately and then the curved surface is stitched together. This avoids the situation where the theoretical cross-section curve shrinks inward or expands outward simultaneously, which occurs when the compensation section is reversed as a whole. This is beneficial for compensating for different deformations in different parts of the blade, improving the compensation qualification rate and machining accuracy, and reducing the number of compensations.

[0019] Polishing is an important machining method to ensure the dimensions of the air intake and exhaust sides. It uses special tools to process the overlapping parts of the air intake and exhaust sides, realizing the integrated machining of the air intake and exhaust side contours, which greatly improves the overall machining efficiency and has good economic benefits. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 This is a schematic diagram of the overall bladed disk shape of the present invention; Figure 2 This is a schematic diagram of the measured cross-section of the integral bladed disk airfoil of the present invention; Figure 3 This is a schematic diagram of the overall bladed disk blade profile compensation section of the present invention; Figure 4 This is a schematic diagram of the overlapping section of the intake side blade basin with different cross sections according to the present invention; Figure 5 This is a schematic diagram of the overlapping section of the intake side blades with different cross sections according to the present invention. Detailed Implementation

[0022] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0023] like Figures 1 to 5 As shown, a method for adjusting the milling deformation of an integral bladed disk includes the following steps: S1: Create the design coordinate points of each section of the blade profile into an editable text format, generate spline curves from the points, establish the theoretical curves of the section profile from the spline curves, and establish the blade profile surface from the theoretical curves of the section profile. S2: Use a coordinate measuring machine to process and inspect the test piece, and output the measured points for each cross section; S3: Import the measured points into the software, and establish spline curves by segmenting the measured values ​​according to the curvature changes. Draw the measured cross section based on the spline curves. S4: Overlap the theoretical section with the measured section, and draw the compensation section by reverse compensation of the motion of the theoretical section and the measured section overlapping; S5: Use the curve mesh command to create the compensated blade basin, blade back, air intake edge, and exhaust edge surfaces respectively, and stitch the surfaces together to create the compensation model. S6: Check all sections to see if they meet the design requirements; if they do not meet the design requirements, repeat S3-S5 to iteratively compensate the existing model. S7: Select the overlapping section of the intake and exhaust edge contours and polish the blades; compare the intake and exhaust edges of different cross-section blade types in the two sections of the blade basin and blade back; design corresponding machining tools for the overlapping section and use the variable axis machining method to machine the intake and exhaust edge contours in one piece.

[0024] In S1, the design coordinate points of each section of the blade are created as editable DAT text, and the spline is generated from the points using the software's command.

[0025] In S1, theoretical curves for each cross section are established using cubic spline curves, and leaf-shaped surfaces are created from these theoretical curves using the curve mesh command.

[0026] The coordinate measuring machine in S2 outputs a DAT file of the measured points, and the output measured points are in a non-fit state.

[0027] The coordinate measuring machine in S2 can automatically divide points according to curvature changes, and parameters can be set to achieve the density of points at different curvature change locations.

[0028] In S3, the measured points are imported into the software, and the measured values ​​are segmented to create cubic spline curves.

[0029] The segmentation principle in S3 is to divide the area into the intake side, exhaust side, blade basin, and blade back according to the curvature change of the measured points; the intake side and exhaust side have a higher density of sampling points than the blade basin and blade back areas.

[0030] In S3, the measured points in the divided areas are used to draw spline curves using the curve-artistic spline command to draw four curve segments: the intake side, exhaust side, blade base, and blade back, forming the measured cross section.

[0031] In the software, S4 uses the alignment command to move the four curves of the measured cross-section—inlet side, exhaust side, blade head, and blade back—to the theoretical cross-section individually, translating and offsetting them to the optimal position.

[0032] S4 replicates the theoretical cross-sectional curve and divides it into four curves—the intake side, exhaust side, blade basin, and blade back—through curvature changes. The replicated theoretical cross-sectional curves are then shifted in the reverse direction using the same shifting parameters to obtain the compensated cross-sectional curves.

[0033] S4 connects the moved curves and forms a complete closed-loop section curve using the bridging curve command in the software. Then, all sections of the airfoil are processed in the same way.

[0034] S5 stitches together the curved surfaces of the blade base, blade back, air intake edge, and air exhaust edge to create a compensated blade model.

[0035] S6 checks whether the design requirements are met. If they are met, the processing is completed; otherwise, S3-S5 are repeated to iteratively compensate the existing model.

[0036] The S7 blade basin has two sections on the back of the blade, with different cross-sectional blade shapes for the inlet and exhaust sides. The corresponding overlapping section machining tool is designed, and the variable axis machining method is used to machine the contours of the inlet and exhaust sides in one piece.

[0037] The coordinate measuring machine is a ZEISS coordinate measuring machine.

[0038] 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. Such 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, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for adjusting the milling deformation of an integral bladed disk blade profile, characterized in that: Includes the following steps: S1: Create the design coordinate points of each section of the blade profile into an editable text format, generate spline curves from the points, establish the theoretical curves of the section profile from the spline curves, and establish the blade profile surface from the theoretical curves of the section profile. S2: Use a coordinate measuring machine to process and inspect the test piece, and output the measured points for each cross section; S3: Import the measured points into the software, and establish spline curves by segmenting the measured values ​​according to the curvature changes. Draw the measured cross section based on the spline curves. S4: Overlap the theoretical section with the measured section, and draw the compensation section by reverse compensation of the motion of the theoretical section and the measured section overlapping; S5: Use the curve mesh command to create the compensated blade basin, blade back, air intake edge, and exhaust edge surfaces respectively, and stitch the surfaces together to create the compensation model. S6: Check all sections to see if they meet the design requirements; if they do not meet the design requirements, repeat S3-S5 to iteratively compensate the existing model. S7: Select the overlapping section of the inlet and exhaust edge contours for blade finishing; compare the inlet and exhaust edges of different cross-section blade types in two sections: the blade basin and the blade back; design corresponding machining tools for the overlapping section, and use a variable axis machining method to machine the inlet and exhaust edge contours in one piece. The coordinate measuring machine in S2 outputs a DAT file of the measured points, indicating a misfit state. The coordinate measuring machine can automatically divide the points based on curvature changes, using the chord tolerance method. The segmentation principle in S3 is as follows: based on the curvature change of the measured points, the area is divided into the intake side, exhaust side, blade base, and blade back; the intake side and exhaust side have a higher density of measurement points than the blade base and blade back areas. The S4 step uses an alignment command in the software to individually move the four curves of the measured cross-section—the inlet side, exhaust side, blade head, and blade back—to the optimal position, translating and offsetting them to the theoretical cross-section. The S4 replicates the theoretical cross-sectional curve and, through curvature changes, divides it into four curves: the intake side, exhaust side, blade head, and blade back. The replicated theoretical cross-sectional curves are then shifted in the reverse direction using the same shifting parameters to obtain the compensated cross-sectional curves. S4 connects the moved curves and forms a complete closed-loop section curve using the bridging curve command in the software. Then, all sections of the blade are processed in the same way.

2. The method for adjusting the milling deformation of an integral bladed disk according to claim 1, characterized in that: In step S1, the design coordinate points of each section of the blade are created as DAT editable text, and the command to generate splines from points is used in the software.

3. The method for adjusting the milling deformation of an integral bladed disk according to claim 2, characterized in that: In S1, theoretical curves for each cross section are established using spline curves, and leaf-shaped surfaces are created from these theoretical curves using the curve mesh command.

4. The method for adjusting the milling deformation of an integral bladed disk according to claim 1, characterized in that: In S3, the measured points in the divided areas are used to draw spline curves using the curve-artistic spline command to draw four curve segments: the intake side, the exhaust side, the blade base, and the blade back, forming the measured cross section.

5. The method for adjusting the milling deformation of an integral bladed disk according to claim 1, characterized in that: S5 involves stitching together the curved surfaces of the blade base, blade back, air intake edge, and air exhaust edge to create a compensated blade model.

Images