Milling and turning combined machining deformation control method for rigid-flexible integrated structural part

Abstract

The invention discloses a rigid-flexible integrated structural member milling and turning combined machining deformation control method which is characterized in that multi-dimensional element suitability optimization of a milling and turning combined machining center is achieved by building a multi-feature tool adaptation model; a machining deformation simulation analysis model is established, and the deformation mechanism and the distribution rule of the cabin structural part in the machining process are analyzed; a low-stress supporting tool is introduced, rigid supporting and flexible adaptation are combined, and a workpiece is comprehensively supported. And a multi-feature cutter adaptive model is applied, so that each cutter can better adapt to the geometrical shape and material characteristics of the workpiece in the machining process, the rigidity distribution of the workpiece and the tool is uniform, and the machining deformation of the workpiece is reduced.

Description

Technical Field

[0001] This invention relates to a method for controlling deformation during milling and turning of rigid-flexible integrated structural parts, belonging to the field of machining deformation control technology. Background Technology

[0002] With the development of spacecraft, the complexity of products and the demand for lightweighting are becoming increasingly stringent. Currently, Lockheed Martin and the Russian Space Agency have upgraded the traditional single-panel welding process to an integrated manufacturing process, striving to reduce stress concentration during the fabrication of the cabin structure. The new generation lunar module adopts a lightweight, high-load-bearing integrated stiffened panel structure design, which, compared to previous manned cabin structures, requires an integrated manufacturing process. During manufacturing, it is crucial to ensure both overall dimensional accuracy and geometric tolerances. The processing quality of large, thin-walled, and weakly rigid cabin structures has always been a major challenge in the aerospace manufacturing field.

[0003] The manufacturing process of weakly rigid cabins is influenced by multiple factors, including machining allowance and process precision, during different stages of the production line. The evolution mechanism of their geometric characteristics is complex, and manufacturing precision is difficult to predict. Traditional machining of large, weakly rigid cabin structural components typically uses rigid fixtures to fix the workpiece. While this method provides some support, the insufficient rigidity of the workpiece itself, coupled with its complex geometry, often leads to significant deformation due to cutting forces. Particularly during milling and turning, uneven force distribution makes it difficult to guarantee machining accuracy, severely impacting surface quality and wall thickness consistency. Furthermore, during cabin machining, the coupled effects of cutting forces, cutting heat, and clamping forces cause machining deformation in the cabin structural components, resulting in poor uniformity of cabin skin wall thickness and failing to meet product machining precision requirements. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method for controlling deformation during milling and turning of rigid-flexible integrated structural parts, thereby reducing workpiece deformation during machining.

[0005] The technical solution of this invention is: This invention discloses a method for deformation control during milling and turning of rigid-flexible integrated structural parts, comprising: Construct a multi-feature tool adaptation model; Based on the multi-feature tool adaptation model, a machining deformation simulation analysis model is established; Using a machining deformation simulation analysis model, the deformation law of the cabin structural components during the machining process is analyzed, and the weak areas of cabin machining deformation are identified. Based on the weak areas of deformation during cabin machining, low-stress support fixtures are selected to support the workpiece; Based on the multi-feature tool adaptation model and combined with the deformation law of the cabin structure during the machining process, a stiffness evolution model of the workpiece and tooling rigid-flexible integrated structure is established under different machining path conditions. Using a stiffness evolution model of the rigid-flexible integrated structure during the processing, with the goal of uniform attenuation of structural stiffness during the processing, the product processing path is obtained. Based on the product processing path, plan the milling and turning composite machining process route for the rigid-flexible integrated structure. Based on the influence of process parameters on processing deformation and surface quality, specific processing parameters are formulated. The workpiece is machined according to the machining process route and parameters of the rigid-flexible integrated structure milling and turning composite machining process.

[0006] Furthermore, in the above method, the construction of the multi-feature tool adaptation model specifically involves: Based on the structural characteristics of the workpiece and the processing requirements, processing features are identified, and a processing feature constraint model is established. Based on the machining feature constraint model, select the appropriate cutting tools and corresponding process parameters; Based on the modeling of machining feature constraints and combined with process parameters, a multi-dimensional element adaptation model of workpiece, tool and process is formed.

[0007] Furthermore, in the above method, the establishment of the processing deformation simulation analysis model specifically includes: Using a coordinate measuring machine or a 3D laser profile scanner, the deformation data of the cabin structure before and after machining is measured, and a visual deformation field of the structure is constructed. Based on deformation data, establish a simulation analysis case for machining deformation; Based on the visualized deformation field and processing deformation simulation analysis examples of the structural components, the processing deformation of the rigid-flexible integrated structural components is analyzed to obtain the weak areas of cabin processing deformation.

[0008] Furthermore, in the above method, the step of selecting low-stress support fixtures to support the workpiece based on the weak deformation areas of the cabin machining specifically involves: Based on the weak areas of deformation during cabin machining, the clamping force is controlled to match the workpiece stiffness, so that the local elastic-plastic response and residual stress distribution meet the requirements. In areas of the cabin where deformation is weak, additional support points are added to ensure the local rigidity of the rigid-flexible integrated structural components; By dynamically adjusting the clamping force, stable clamping is ensured while minimizing deformation.

[0009] Furthermore, in the above method, a stiffness evolution model for the processing of a rigid-flexible integrated structure is used, with the goal of uniformly reducing the structural stiffness during processing, to obtain the product processing path. The specific method is as follows: The processing procedure is simplified into steps including roughing, semi-finishing, and finishing. Calculate the product stiffness and evolution path when using typical nodes; Add low-stress support fixtures to the weak areas of the cabin during machining to make the stiffness decrease evenly. Adjust the rigidity of the fixture in real time to ensure that the accuracy and stability during the machining process meet the requirements; Based on the stiffness evolution model of the workpiece and tooling integrated rigid-flexible structure during the machining process, the product machining path is obtained.

[0010] Furthermore, in the above method, the specific processing parameters are formulated based on the influence of process parameters on processing deformation and surface quality. The specific method is as follows: Obtain input parameters and establish dynamic equations for multiple degrees of freedom in the milling process; input parameters include cutting force coefficients, system dynamic parameters, process parameters, and tool geometry; Based on the dynamic equations of the degrees of freedom, a milling stability leaf lobe diagram (SLD) is constructed, and the milling stability leaf lobe diagram (SLD) of the milling process is obtained using the time-frequency method. The stable region is obtained based on the milling stability lobe diagram (SLD) of the milling process. Determine the optimal cutting parameters in the stable region.

[0011] The advantages of this invention over the prior art are as follows: (1) This invention provides a method for controlling deformation during milling and turning of rigid-flexible integrated structural parts, which can effectively control the deformation during processing of large thin-walled weak rigid cabin structures, improve the processing quality and accuracy of cabin structures, and ensure the high reliability and consistency of the final product.

[0012] (2) This invention analyzes the stiffness changes of the cabin during machining through precise modeling, and formulates a targeted machining strategy aimed at uniform attenuation of structural stiffness and suppression of cutting chatter during machining. Low-stress support fixtures are developed, which can provide sufficient stiffness support without increasing clamping stress, reducing stress concentration during machining. Optimal cutting parameters are determined in the stable region by constructing a milling stability lobe diagram (SLD). This ensures synchronous balance of machining loads and uniform evolution of stiffness, thereby achieving uniform release and transfer of strain energy.

[0013] (3) By introducing low-stress support fixtures, the present invention combines rigid support with flexible adaptation to provide comprehensive support for the workpiece; enabling each tool to better adapt to the geometry and material properties of the workpiece during the processing, uniformly distributing the stiffness of the workpiece and the fixture, and reducing the processing deformation of the workpiece.

[0014] (4) By applying a multi-feature tool adaptation model, this invention enables each tool to better adapt to the geometry and material properties of the workpiece during the machining process, uniformly distributes the stiffness of the workpiece and the tooling, and reduces the machining deformation of the workpiece. (5) This invention achieves real-time compensation of machining tool position by introducing online measurement of multi-dimensional signals such as light / sound. Attached Figure Description

[0015] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown, this invention discloses a method for deformation control during milling and turning of rigid-flexible integrated structural parts, comprising: Construct a multi-feature tool adaptation model; Based on the multi-feature tool adaptation model, a machining deformation simulation analysis model is established; Using a machining deformation simulation analysis model, the deformation law of the cabin structural components during the machining process is analyzed, and the weak areas of cabin machining deformation are identified. Based on the weak areas of deformation during cabin machining, low-stress support fixtures are selected to support the workpieces; Based on the multi-feature tool adaptation model and combined with the deformation law of the cabin structure during the machining process, a stiffness evolution model of the workpiece and tooling rigid-flexible integrated structure is established under different machining path conditions. Using a stiffness evolution model of the rigid-flexible integrated structure during the processing, with the goal of uniform attenuation of structural stiffness during the processing, the product processing path is obtained. Based on the product processing path, plan the machining process route for the rigid-flexible integrated structure milling and turning; consider the processing continuity and the convenience of tooling adjustment to form the machining process route; Based on the influence of process parameters on processing deformation and surface quality, specific processing parameters are formulated. The workpiece is machined according to the machining process route and parameters of the rigid-flexible integrated structure milling and turning composite machining process.

[0018] Preferably, a multi-feature tool adaptation model is constructed, specifically as follows: Based on the structural characteristics of the workpiece and the processing requirements, processing features are identified, and a processing feature constraint model is established. Based on the machining feature constraint model, select the appropriate cutting tools and corresponding process parameters; Based on the modeling of machining feature constraints and combined with process parameters, a multi-dimensional element adaptation model of workpiece, tool and process is formed.

[0019] Preferably, a simulation analysis model for processing deformation is established, specifically as follows: Using a coordinate measuring machine or a 3D laser profile scanner, the deformation data of the cabin structure before and after machining is measured, and a visual deformation field of the structure is constructed. Based on deformation data, establish a simulation analysis case for machining deformation; Based on the visualization deformation field and processing deformation simulation analysis examples of structural components, the processing deformation of rigid-flexible integrated structural components is analyzed to identify the weak areas of cabin processing deformation.

[0020] Preferably, based on the weak areas of deformation during cabin machining, low-stress support fixtures are selected to support the workpiece, specifically as follows: Based on the weak areas of deformation during cabin machining, the clamping force is controlled to match the workpiece stiffness, so that the local elastic-plastic response and residual stress distribution meet the requirements. In areas of the cabin where deformation is weak, additional support points are added to ensure the local rigidity of the rigid-flexible integrated structural components; By dynamically adjusting the clamping force, stable clamping is ensured while minimizing deformation.

[0021] Preferably, a stiffness evolution model for the processing of a rigid-flexible integrated structure is used, with the goal of uniformly reducing the structural stiffness during processing, to obtain the product processing path. The specific method is as follows: The processing procedure is simplified into steps including roughing, semi-finishing, and finishing. Calculate the product stiffness and evolution path when using typical nodes; Add low-stress support fixtures to the weak areas of the cabin during machining to make the stiffness decrease evenly. Adjust the rigidity of the fixture in real time to ensure that the accuracy and stability during the machining process meet the requirements; Based on the stiffness evolution model of the workpiece and tooling integrated rigid-flexible structure during the machining process, the product machining path is obtained.

[0022] Preferably, based on the influence of process parameters on processing deformation and surface quality, specific processing parameters are formulated. The specific method is as follows: Obtain input parameters and establish dynamic equations for multiple degrees of freedom in the milling process; input parameters include cutting force coefficients, system dynamic parameters, process parameters, and tool geometry; Based on the dynamic equations of the degrees of freedom, a milling stability leaf lobe diagram (SLD) is constructed, and the milling stability leaf lobe diagram (SLD) of the milling process is obtained using the time-frequency method. The stable region is obtained based on the milling stability lobe diagram (SLD) of the milling process. Determine the optimal cutting parameters in the stable region.

[0023] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0024] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for controlling deformation during milling and turning of rigid-flexible integrated structural parts, characterized in that, include: Construct a multi-feature tool adaptation model; Based on the multi-feature tool adaptation model, a machining deformation simulation analysis model is established; Using a machining deformation simulation analysis model, the deformation law of the cabin structural components during the machining process is analyzed, and the weak areas of cabin machining deformation are identified. Based on the weak areas of deformation during cabin machining, low-stress support fixtures are selected to support the workpiece; Based on the multi-feature tool adaptation model and combined with the deformation law of the cabin structure during the machining process, a stiffness evolution model of the workpiece and tooling rigid-flexible integrated structure is established under different machining path conditions. Using a stiffness evolution model of the rigid-flexible integrated structure during the processing, with the goal of uniform attenuation of structural stiffness during the processing, the product processing path is obtained. Based on the product processing path, plan the milling and turning composite machining process route for the rigid-flexible integrated structure. Based on the influence of process parameters on processing deformation and surface quality, specific processing parameters are formulated. The workpiece is machined according to the machining process route and parameters of the rigid-flexible integrated structure milling and turning composite machining process.

2. The deformation control method for milling and turning composite machining of rigid-flexible integrated structural parts according to claim 1, characterized in that, The construction of the multi-feature tool adaptation model specifically involves: Based on the structural characteristics of the workpiece and the processing requirements, processing features are identified, and a processing feature constraint model is established. Based on the machining feature constraint model, select the appropriate cutting tools and corresponding process parameters; Based on the modeling of machining feature constraints and combined with process parameters, a multi-dimensional element adaptation model of workpiece, tool and process is formed.

3. The deformation control method for milling and turning composite machining of rigid-flexible integrated structural parts according to claim 1, characterized in that, The establishment of the processing deformation simulation analysis model specifically includes: Using a coordinate measuring machine or a 3D laser profile scanner, the deformation data of the cabin structure before and after machining is measured, and a visual deformation field of the structure is constructed. Based on deformation data, establish a simulation analysis case for machining deformation; Based on the visualized deformation field and processing deformation simulation analysis examples of the structural components, the processing deformation of the rigid-flexible integrated structural components is analyzed to obtain the weak areas of cabin processing deformation.

4. The deformation control method for milling and turning composite machining of rigid-flexible integrated structural parts according to claim 1, characterized in that, The step of selecting low-stress support fixtures to support the workpiece based on the weak deformation areas of the cabin machining is as follows: Based on the weak areas of deformation during cabin machining, the clamping force is controlled to match the workpiece stiffness, so that the local elastic-plastic response and residual stress distribution meet the requirements. In areas of the cabin where deformation is weak, additional support points are added to ensure the local rigidity of the rigid-flexible integrated structural components; By dynamically adjusting the clamping force, stable clamping is ensured while minimizing deformation.

5. The deformation control method for milling and turning composite machining of rigid-flexible integrated structural parts according to claim 1, characterized in that: Using a stiffness evolution model of the rigid-flexible integrated structure during processing, and aiming at the uniform attenuation of structural stiffness during processing, the product processing path is obtained. The specific method is as follows: The processing procedure is simplified into steps including roughing, semi-finishing, and finishing. Calculate the product stiffness and evolution path when using typical nodes; Add low-stress support fixtures to the weak areas of the cabin during machining to make the stiffness decrease evenly. Adjust the rigidity of the fixture in real time to ensure that the accuracy and stability during the machining process meet the requirements; Based on the stiffness evolution model of the workpiece and tooling integrated rigid-flexible structure during the machining process, the product machining path is obtained.

6. The deformation control method for milling and turning composite machining of rigid-flexible integrated structural parts according to claim 1, characterized in that, Based on the influence of process parameters on processing deformation and surface quality, specific processing parameters are formulated. The specific method is as follows: Obtain input parameters and establish dynamic equations for multiple degrees of freedom in the milling process; input parameters include cutting force coefficients, system dynamic parameters, process parameters, and tool geometry; Based on the dynamic equations of the degrees of freedom, a milling stability leaf lobe diagram (SLD) is constructed, and the milling stability leaf lobe diagram (SLD) of the milling process is obtained using the time-frequency method. The stable region is obtained based on the milling stability lobe diagram (SLD) of the milling process. Determine the optimal cutting parameters in the stable region.

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