Modeling and machining method and system for engine blade split

Abstract

The invention discloses a modeling and machining method and system for an engine blade split, and belongs to the technical field of aero-engine blade machining.The method comprises the steps that a plurality of blade profile section contour lines are obtained, segmentation processing is carried out, an initial entity is constructed, an initial split sheet body is generated, a first V curve set is constructed, and V curves of a target area are screened out; forming a second V curve group, constructing a first middle sheet body and extending the first middle sheet body to a preset boundary, constructing a third V curve group, obtaining a boundary curve of the first middle sheet body, and adjusting the boundary curve to the blank size; based on the adjusted boundary curve and the third V curve group, constructing a target split model; carrying out rough milling on the blank; the rough-milled blank is subjected to finish milling; and the surface subjected to finish milling is ground, and machining is completed. On the basis of ensuring the high quality and machinability of the model, the modeling process is simplified, the machining operability is improved, and the machining precision and reliability of the aero-engine blade are optimized.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine blade processing technology, specifically relating to a modeling and processing method and system for the mid-section of an engine blade. Background Technology

[0002] With the continuous improvement of aero-engines, the structure of compressor blades has evolved from solid to hollow. One example of a hollow adjustable blade structure for an aero-engine is shown below. Figure 1 To reduce weight, it has five closed cavities that vary with the blade profile. The blade is connected to the blade base and diffuser surface via a diffusion joint, followed by machining processes such as milling to produce a finished part that meets requirements. Currently, diffusion welding results in large deformation and poor consistency, leading to significant differences in the reference datum of subsequent machining surfaces and out-of-tolerance cavity wall thickness after machining. The machining quality of the diffusion joint surface directly affects the welding quality; therefore, it is necessary to improve the machining quality of the diffusion joint surface to enhance welding quality. Since the closed cavities of the blade profile vary with the blade profile, the welding surface must be the blade split surface. The structure of the blade split surface is relatively complex, making machining difficult and compromising machining accuracy and efficiency. Summary of the Invention

[0003] This invention provides a modeling and machining method and system for the split surface of an engine blade, aiming to solve the problem that the current blade profile is complex, as the closed cavity of the blade changes with the blade profile, and its welding surface must be the split surface of the blade. This makes machining difficult and the accuracy and efficiency of machining hard to guarantee.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for modeling and machining the mid-face of an engine blade, comprising the following steps: S1. Obtain multiple airfoil section contours based on the airfoil profile; segment each airfoil section contour; construct an initial solid based on the segmented airfoil section contours; generate an initial mid-section sheet based on the initial solid; construct a first V-curve group based on the initial mid-section sheet; select the V-curves of the target region from the first V-curve group to form a second V-curve group; construct a first intermediate sheet based on the second V-curve group and extend the first intermediate sheet to a preset boundary; construct a third V-curve group based on the extended first intermediate sheet and obtain the boundary curves of the first intermediate sheet; adjust the boundary curves to the blank size; construct the target mid-section model based on the adjusted boundary curves and the third V-curve group. S2. Based on the target split surface model, perform rough milling to remove large allowances on the blank; perform fine milling on the rough milled blank to achieve the preset surface accuracy and surface roughness; perform grinding on the fine milled surface to remove milling marks, thus completing the machining of the engine blade split surface.

[0005] In some implementations, in S1, obtaining multiple blade profile contour lines based on the blade profile specifically includes: equidistantly cutting the blade profile to obtain multiple blade profile contour lines.

[0006] In some implementations, in S1, segmenting the profile lines of each airfoil section specifically includes dividing each airfoil profile line into an inlet edge line segment, an exhaust edge line segment, a blade base line segment, and a blade back line segment.

[0007] In some implementations, in S1, constructing an initial solid based on the segmented blade section profile specifically includes: performing surface group operations on the blade section profile and stretching it into a solid while retaining its shape.

[0008] Furthermore, in S1, generating the initial mid-face sheet based on the initial entity specifically includes: selecting the leaf basin part and leaf back part on the initial entity through mid-face pairing operation to generate the initial mid-face sheet.

[0009] Furthermore, in S1, selecting the V curves of the target region from the first V curve group to form the second V curve group specifically includes: deleting the V curves corresponding to the exhaust edge in the first V curve group, and retaining the V curves corresponding to the leaf basin and leaf back to form the second V curve group.

[0010] In some implementations, in S1, the preset boundary is 1 mm beyond the envelope blade where the first intermediate sheet extends.

[0011] In some implementations, in S2, rough milling of the blank based on the target split surface model is performed by using a flat-end cutter on a four-axis machining center; finish milling of the blank after rough milling is performed by high-speed milling using a ball end mill on a five-axis machining center based on the target split surface model.

[0012] In some implementations, in S2, the contour of the precision milling is controlled within 0.05 mm, the surface roughness is Ra0.8, and the amount of material removed by grinding is controlled within 0.02 mm.

[0013] This invention also provides a modeling and machining system for the mid-section of an engine blade. The system is used to implement the aforementioned modeling and machining method for the mid-section of an engine blade. The system includes an initial mid-section sheet module, a first intermediate sheet module, a target mid-section model, and a mid-section machining module; wherein: Initial Split Facet Module: Used to obtain multiple airfoil section contours based on the airfoil profile; segment each airfoil section contour; construct an initial solid based on the segmented airfoil section contours; generate an initial split facet based on the initial solid; First intermediate sheet module: used to construct a first V-curve group based on the initial mid-section sheet; to select the V-curve of the target region from the first V-curve group to form a second V-curve group; to construct the first intermediate sheet based on the second V-curve group, and to extend the first intermediate sheet to a preset boundary; Target mid-face model: used to construct the third V-curve group based on the extended first intermediate sheet and obtain the boundary curve of the first intermediate sheet; adjust the boundary curve to the raw material size; construct the target mid-face model based on the adjusted boundary curve and the third V-curve group; Split-face machining module: Used to preset the profile parameters of engine blades, providing data support for the subsequent machining of the split-face of engine blades.

[0014] Compared with the prior art, the present invention provides a modeling and processing method and system for the mid-face of an engine blade, which has the following advantages: This invention discloses a modeling and machining method for the split surface of engine blades, improving upon the challenges of poor machining quality and low consistency in the diffusion connection surface of hollow aero-engine blades. Through a digital modeling process, it achieves a reliable method for transforming virtual models into physical entities. In the modeling stage, this invention employs a systematic process based on segmented processing of cross-sectional contour lines, constructing initial entities, and generating initial split surfaces. This process generates the target split surface model through multiple rounds of V-curve group selection and reconstruction, ensuring the rigor and repeatability of the model generation process. By selecting target regions from the initial V-curve group, it eliminates areas with poor surface smoothness due to abrupt curvature changes, such as exhaust edges, thus avoiding geometric defects such as irregular distortions in the final split surface model and guaranteeing the high quality and machinability of the model itself. This invention uses the optimized digital model as input for subsequent machining operations. Through three machining stages—rough milling, finish milling, and grinding—precise modeling supports the final surface geometry of the formed blade, eliminating machining deviations caused by differences in model datum or inherent model defects. This improves the machining accuracy and reliability of aero-engine blades and has practical value. Attached Figure Description

[0015] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0016] Figure 1 This is a schematic diagram of the blade structure in the modeling and processing method of the split surface of an engine blade according to the present invention; Figure 2 This is a schematic diagram of the first stage of the blade surface modeling process in the modeling and processing method of the engine blade surface of the present invention; Figure 3 This is a schematic diagram of the second stage of the blade surface modeling process in the modeling and processing method of the engine blade surface of the present invention; Figure 4 This is a schematic diagram of the third stage of the blade surface modeling process in the modeling and processing method of the engine blade surface of the present invention; Figure 5 This is a schematic diagram of the fourth stage of the blade surface modeling process in the modeling and processing method of the engine blade surface of the present invention; Figure 6 This is a schematic diagram of the fifth stage of the blade surface modeling process in the engine blade surface modeling and processing method of the present invention; Figure 7 This is a schematic diagram of the sixth stage of the blade surface modeling process in the modeling and processing method of the engine blade surface of the present invention.

[0017] Figure 8 This is a schematic diagram of the seventh stage of the blade surface modeling process in the modeling and machining method for engine blade surface of the present invention. Figure 9 This is a schematic diagram of the eighth stage of the blade surface modeling process in the modeling and machining method for engine blade surface of the present invention. Figure 10 This is a schematic diagram of the facet machining process in the modeling and machining method for facets in an engine blade according to the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0021] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0022] Furthermore, the functional modules in the various embodiments described herein can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part. Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of the present invention. After reading the above content, various modifications and substitutions of the present invention will be obvious to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0023] like Figure 1-10 As shown, the present invention provides a method for modeling and machining the facets of an engine blade, comprising the following steps: S1. Obtain multiple airfoil section contours based on the airfoil profile; segment each airfoil section contour; construct an initial solid based on the segmented airfoil section contours; generate an initial mid-section sheet based on the initial solid; construct a first V-curve group based on the initial mid-section sheet; select the V-curves of the target region from the first V-curve group to form a second V-curve group; construct a first intermediate sheet based on the second V-curve group and extend the first intermediate sheet to a preset boundary; construct a third V-curve group based on the extended first intermediate sheet and obtain the boundary curves of the first intermediate sheet; adjust the boundary curves to the blank size; construct the target mid-section model based on the adjusted boundary curves and the third V-curve group. S2. Based on the target split surface model, perform rough milling to remove large allowances on the blank; perform fine milling on the rough milled blank to achieve the preset surface accuracy and surface roughness; perform grinding on the fine milled surface to remove milling marks, thus completing the machining of the engine blade split surface.

[0024] Compared to the traditional theoretical model of points, lines, and surfaces, the method of this invention simplifies the complex and tedious modeling process. Points are the centers of the circles tangent to the blade base and blade back within each cross-section; lines are the connections between the centers of n tangent circles; and surfaces are formed by stretching the lines connecting the centers of the tangent circles of each cross-section. Furthermore, the model is optimized to ensure smoothness of the modeled surfaces. The portion of the mid-section that extends from the part boundary to the blank boundary does not extend naturally, resulting in excessive edge curvature; instead, it transitions smoothly, reducing welding difficulty and increasing welding strength. The profile of the machined mid-section is controlled within 0.05mm, and the roughness reaches Ra0.4, providing technical support for reducing diffusion welding deformation.

[0025] In some embodiments, this invention generates multiple airfoil cross-sectional contour lines using an equidistant interception method, ensuring that the data points acquired along the airfoil axis are uniformly distributed. This provides a geometric data foundation for the split-face model and improves the reliability of the entire modeling process. This invention decomposes the complex airfoil cross-sectional geometry into the inlet edge, exhaust edge, blade base, and blade back, enabling the system to individually identify and process each segment. This allows for targeted modeling strategies for different regions, resulting in more efficient generation of high-quality split-face models. Furthermore, this invention, through surface group operations and shape-preserving extrusion, ensures that the complex geometric features of the airfoil cross-section are fully preserved during the solidification process. The generated initial solid accurately reflects the actual shape of the airfoil, providing a realistic and accurate volume reference model for generating the split-face.

[0026] This invention uses a mid-surface pairing operation and selects the portion corresponding to the leaf base and leaf back on the initial entity. Based on the geometric relationship of the leaf body entity, it calculates the mid-surface region located between the leaf base and leaf back. This method is more accurate and faster, and has an inherent correlation with the entity model, directly affecting subsequent curve selection and sheet reconstruction. It transforms the search for the mid-surface into a repeatable geometry-based operation.

[0027] The present invention selects V curves of the target region from the first V curve group to form the second V curve group. Specifically, this includes: deleting the V curves corresponding to the exhaust edge in the first V curve group, retaining the V curves corresponding to the blade base and blade back to form the second V curve group, discarding the mid-plane curve generated in the geometrically complex and curvature-drastic region of the exhaust edge, and retaining the V curves corresponding to the blade base and blade back. The invention uses curves with relatively smooth geometric shapes and higher quality to reconstruct the surface, thereby avoiding the generation of poor geometry and ensuring that the constructed second V curve group has excellent smoothness and machinability.

[0028] This invention, based on a target mid-surface model, performs rough milling on the blank using a flat-end mill on a four-axis machining center. Then, based on the same model, it performs finish milling on the blank using a ball-end mill on a five-axis machining center. This approach optimizes cost while maintaining accuracy and efficiency. Rough milling on the four-axis machining center utilizes the high rigidity and efficiency of the machine tool, along with the high metal removal rate of the flat-end mill, to quickly and stably remove most of the machining allowance. Finish milling on the five-axis machining center uses a ball-end mill for high-speed milling, achieving precise shaping of complex curved surfaces. The combination of the ball-end mill and high-speed milling results in a surface with excellent quality. The finish milling process of this invention controls the contour within 0.05 mm, achieving a surface roughness of Ra0.8, while the grinding removal is controlled within 0.02 mm, collectively defining a surface condition suitable for high-quality diffusion welding.

[0029] This invention also provides a modeling and machining system for the mid-section of an engine blade. The system is used to implement the aforementioned modeling and machining method for the mid-section of an engine blade. The system includes an initial mid-section sheet module, a first intermediate sheet module, a target mid-section model, and a mid-section machining module; wherein: Initial Split Facet Module: Used to obtain multiple airfoil section contours based on the airfoil profile; segment each airfoil section contour; construct an initial solid based on the segmented airfoil section contours; generate an initial split facet based on the initial solid; First intermediate sheet module: used to construct a first V-curve group based on the initial mid-section sheet; to select the V-curve of the target region from the first V-curve group to form a second V-curve group; to construct the first intermediate sheet based on the second V-curve group, and to extend the first intermediate sheet to a preset boundary; Target mid-face model: used to construct the third V-curve group based on the extended first intermediate sheet and obtain the boundary curve of the first intermediate sheet; adjust the boundary curve to the raw material size; construct the target mid-face model based on the adjusted boundary curve and the third V-curve group; Split-face machining module: Used to preset the profile parameters of engine blades, providing data support for the subsequent machining of the split-face of engine blades.

[0030] The system of the present invention provides a dedicated system for the present invention by setting up an initial mid-face piece module, a first intermediate piece module, a target mid-face model module, and a mid-face processing module, which has certain practical significance.

[0031] The following detailed description of a modeling and processing method and system for the mid-face of an engine blade according to the present invention will be provided through specific embodiments.

[0032] A method for modeling and machining the facets of an engine blade, specifically including the following: like Figure 1 The image shows the structure of a hollow adjustable guide vane for a certain type of engine. The vane is made of titanium alloy and is a double-journey hollow blade with five enclosed internal cavities that change with the blade profile. The faceting process is achieved through the following steps: I. Mid-plane modeling: 1) such as Figure 2 As shown, n blade profile lines are equidistantly cut from the blade surface; 2) such as Figure 3 As shown, the airfoil cross-sectional profile is divided into four segments: the inlet edge, the exhaust edge, the blade base, and the blade back. 3) such as Figure 4 As shown, the blade section is stretched into a solid shape by using a surface group while retaining its shape; 4) such as Figure 5 As shown, by selecting the leaf basin and the back of the leaf through mid-surface pairing, a leaf-shaped mid-section is generated; 5) such as Figure 6 As shown, 20 V curves are regenerated from the split-face body using isoparametric curves; 6) For example Figure 7 As shown, the generated V curve is removed from the exhaust edge portion and re-stretched into a sheet (since the exhaust edge portion is not smooth and irregular, the mid-section surface extended from the exhaust edge portion will produce an irregular shape), and the sheet is extended to 1mm outside the envelope blade. 7) For example Figure 8 As shown, the V-curve is regenerated using the extended sheet body, and the edge curve is translated to the fabric size; 8) For example Figure 9As shown, the translated edge curve and the generated V curve are used to generate a new sheet body through a surface group, and extended longitudinally to the size of the raw material. Finally, a machinable split surface is formed by the U curve of the extended sheet body.

[0033] II. Processing of the center-parted surface: 1) Rough milling is performed on a four-axis machining center. The blank is placed on the machine tool platform, and it is positioned and clamped from all four sides. A Φ32R6 flat end mill is used to remove the large amount of material.

[0034] 2) such as Figure 10 As shown, the finish milling was performed on a five-axis machining center using a Φ10 ball end mill at high speed. The profile was controlled within 0.05mm, and the milling roughness reached Ra0.8.

[0035] 3) Use belt grinding to remove milling marks to complete the machining of the split surface, removing less than 0.02mm, and complete the machining of the blade.

[0036] In summary, the present invention provides a modeling and machining method and system for the split surface of engine blades. By ensuring the split surface, a critical characteristic of the final part, this end-to-end solution meets extremely stringent quality requirements, improving the manufacturing quality and reliability of core components of aero-engines and providing technical support for ensuring engine performance.

[0037] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Anyone skilled in the art can readily implement the present invention according to the description and above. Any modifications, alterations, or variations made based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A method of modeling and machining a midspan of an engine vane, characterized by, Comprise the following steps: S1, based on the blade profile obtains a plurality of blade section profile lines; each blade section profile line is segmented; based on the segmented blade section profile line, an initial entity is constructed; based on the initial entity, an initial middle surface sheet is generated; based on the initial middle surface sheet, a first V curve group is constructed; the V curve of the target area is selected from the first V curve group to form a second V curve group; based on the second V curve group, a first intermediate sheet is constructed, and the first intermediate sheet is extended to a preset boundary; based on the extended first intermediate sheet, a third V curve group is constructed, and a boundary curve of the first intermediate sheet is obtained; the boundary curve is adjusted to the size of the raw material; based on the adjusted boundary curve and the third V curve group, a target middle surface model is constructed; S2, based on the target middle surface model, the rough milling of the blank is removed; the rough milling of the blank is performed to achieve the preset surface roughness and the surface roughness of the precision milling; the surface of the precision milling is removed by milling and grinding, and the processing of the middle surface of the engine blade is completed.

2. The method of modeling and machining a section of an engine blade according to claim 1, wherein, In the S1, based on the blade profile, a plurality of blade section profile lines are obtained, which specifically comprises: the blade profile is equally intercepted to obtain a plurality of blade section profile lines.

3. The method of modeling and machining a split in an engine vane blade of claim 1, wherein, In the S1, each blade section profile line is segmented, which specifically comprises: each blade section profile line is divided into an inlet edge line segment, an exhaust edge line segment, a blade basin line segment and a blade back line segment.

4. The method of modeling and machining a split in an engine vane according to claim 1, wherein, In the S1, based on the segmented blade section profile line, an initial entity is constructed, which specifically comprises: the blade section profile line is operated by surface group, and the shape is stretched to an entity.

5. The method of modeling and machining a split in an engine vane blade of claim 3, wherein, In the S1, based on the initial entity, an initial middle surface sheet is generated, which specifically comprises: through the middle surface pairing operation, the initial entity corresponding to the blade basin part and the blade back part is selected to generate the initial middle surface sheet.

6. The method of modeling and machining a split in an engine vane blade of claim 3, wherein, In the S1, the V curve of the target area is selected from the first V curve group to form a second V curve group, which specifically comprises: the V curve corresponding to the exhaust edge in the first V curve group is deleted, and the V curve corresponding to the blade basin and the blade back is retained to form the second V curve group.

7. The method of modeling and machining a split in an engine vane blade of claim 1, wherein, In the S1, the preset boundary is that the first intermediate sheet is extended to 1mm outside the envelope blade.

8. The method of modeling and machining a split in an engine vane blade of claim 1, wherein, In the S2, based on the target middle surface model, the rough milling of the blank is performed by using a flat bottom cutter on a four-coordinate machining center; based on the target middle surface model, the rough milling of the blank is performed by using a ball head cutter on a five-axis machining center.

9. The method of modeling and machining a split in an engine vane blade of claim 1, wherein, In the S2, the profile control of the precision milling is within 0.05mm, the surface roughness is Ra0.8, and the removal amount of the grinding processing is controlled within 0.02mm.

10. A system for modeling and machining of an engine vane midsection, comprising: The system is used to realize the modeling and processing method of the middle surface of the engine blade in any one of claims 1-9, and the system comprises an initial middle surface sheet module, a first intermediate sheet module, a target middle surface model and a middle surface processing module; wherein: The initial middle surface sheet body module is used to obtain a plurality of blade profile section contour lines based on a blade body profile, segment each blade profile section contour line, construct an initial entity based on the segmented blade profile section contour line, and generate an initial middle surface sheet body based on the initial entity. The first intermediate sheet body module is used to construct a first V curve group based on the initial middle surface sheet body, select V curves of a target region from the first V curve group to form a second V curve group, construct a first intermediate sheet body based on the second V curve group, and extend the first intermediate sheet body to a preset boundary. The target middle surface model is used to construct a third V curve group based on the extended first intermediate sheet body, obtain a boundary curve of the first intermediate sheet body, adjust the boundary curve to a raw material size, and construct a target middle surface model based on the adjusted boundary curve and the third V curve group. The middle surface processing module is used to preset a profile parameter of an engine blade, and provide data support for subsequent processing of the middle surface of the engine blade.

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