Thin-wall part machining method and device, computer storage medium and terminal

Abstract

According to the thin-wall part machining method and device, the computer storage medium and the terminal, the area with the maximum residual stress in the thin-wall part blank is recognized before rough machining, the recognized area with the maximum residual stress is removed through a symmetric breaking method, the residual stress is released in advance, and the machining efficiency is improved. Controllable deformation generated after rough machining of the blank can be triggered in advance, the deformation condition of the workpiece in the subsequent machining process is more predictable, effective control over workpiece deformation is achieved, and the situation that due to improper stress release, the workpiece suddenly deforms in the subsequent machining process and cannot be corrected in time, and consequently the workpiece is scrapped is avoided. After the residual stress is effectively released, deformation caused by early-stage machining is reserved, correction is conducted in the rough machining stage and the finish machining stage through the deformation resisting technology, the deformation of the blank is released in the subsequent machining process, the appearance precision of the workpiece is guaranteed, and the rejection rate of the workpiece is reduced; and material waste and reprocessing cost caused by workpiece scrapping are reduced, and the processing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to intelligent manufacturing technology, in particular to a method and device for processing a thin-walled part, a computer storage medium and a terminal. BACKGROUND

[0002] In the field of aerospace equipment manufacturing, structural parts such as frames, beams, panels and skins usually have the characteristics of thin wall thickness, large size, low stiffness and complex structure in order to effectively reduce weight and improve fuel efficiency. Among them, large aluminum alloy thin-walled frame parts (hereinafter referred to as thin-walled parts) are prone to deformation after processing. Research has found that in most cases, the deformation is mainly caused by the redistribution of internal stress field of the blank caused by material removal.

[0003] At present, in the processing of aluminum alloy thin-walled parts, the influence of processing sequence on the stress release sequence of thin-walled parts is not well understood. The processing strategy in the related art often does not fully consider the residual stress distribution of the blank. If the stress release is not properly arranged during the processing, it may cause sudden large deformation of the workpiece in the later processing stage, which cannot be corrected in time and thus scrapped, resulting in material waste and cost increase.

[0004] In summary, how to release stress, effectively control deformation in the early processing stage, ensure the shape accuracy of the workpiece in the finishing stage, and reduce the workpiece rejection rate, has become a problem to be solved. SUMMARY

[0005] The embodiment of the present application provides a method for processing a thin-walled part, comprising: identifying a maximum residual stress region in a blank before rough machining of the thin-walled part; removing the identified maximum residual stress region to release the residual stress of the maximum residual stress region; retaining the deformation caused by the previous processing of the thin-walled part after releasing the residual stress, and correcting the retained deformation in the subsequent processing through an anti-deformation technology; The subsequent processing includes rough machining and finishing.

[0006] On the other hand, the embodiment of the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program, and the computer program is executed by a processor to implement the above-mentioned method for processing a thin-walled part.

[0007] In another aspect, the embodiment of the present application also provides a terminal, comprising a memory and a processor, and the memory stores a computer program; wherein, the processor is configured to execute the computer program in the memory; The computer program is executed by the processor to implement the above-mentioned method for processing a thin-walled part.

[0008] Yet in another aspect, the embodiments of the present application also provide a device for processing a thin-walled workpiece, comprising: an identifying unit, a removing unit and a deformation processing unit; wherein, the identifying unit is configured to identify a maximum residual stress area in a thin-walled workpiece blank before rough machining; the removing unit is configured to remove the identified maximum residual stress area to release residual stress of the maximum residual stress area; the deformation processing unit is configured to retain the deformation caused by the previous machining of the thin-walled workpiece after the release of the residual stress, and correct the retained deformation through an anti-deformation technology in the subsequent machining process; wherein the subsequent machining includes rough machining and finish machining.

[0009] The embodiments of the present application identify the maximum residual stress area in the thin-walled workpiece blank before rough machining, remove the identified maximum residual stress area through a symmetry breaking method, realize the early release of residual stress, can cause the blank to produce controllable deformation after the completion of rough machining, make the deformation of the workpiece in the subsequent machining more predictable, realize effective control of the deformation of the workpiece, avoid the workpiece from being scrapped due to sudden deformation in the subsequent machining caused by improper stress release; after the effective release of residual stress, the deformation caused by the previous machining is retained, and the anti-deformation technology is used to correct in the rough machining and finish machining stages, so that the blank releases deformation in the subsequent machining process, ensures the shape accuracy of the workpiece, reduces the scrap rate of the workpiece, reduces the material waste and reprocessing cost caused by the scrapping of the workpiece, and improves the processing efficiency.

[0010] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. Other advantages of the present application can be realized and obtained by means of the solutions described in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0011] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the embodiments of the present application together with the embodiments of the present application, and do not constitute a limitation to the technical solutions of the present application.

[0012] Figure 1 a flowchart of the method for processing a thin-walled workpiece according to the embodiments of the present application; Figure 2 a structural block diagram of the device for processing a thin-walled workpiece according to the embodiments of the present application; Figure 3 a schematic diagram of removing a maximum residual stress area according to the embodiments of the present application; Figure 4 a schematic diagram of removing another maximum residual stress area according to the embodiments of the present application; Figure 5 Another schematic diagram of removing the maximum residual stress area for an embodiment of the present disclosure; Figure 6 Another schematic diagram of removing the maximum residual stress area for an embodiment of the present disclosure; Figure 7 A schematic diagram of stress curves for an embodiment of the present disclosure; Figure 8 A schematic diagram of removing the maximum residual stress area layer by layer for an embodiment of the present disclosure; Figure 9 A schematic diagram of removing the maximum residual stress area block by block for an embodiment of the present disclosure; Figure 10 A schematic diagram of a principle of retaining deformation following previous processing for an embodiment of the present disclosure; Figure 11 Another schematic diagram of a principle of retaining deformation following previous processing for an embodiment of the present disclosure; Figure 12 Another schematic diagram of a principle of retaining deformation following previous processing for an embodiment of the present disclosure; Figure 13 Another schematic diagram of a principle of retaining deformation following previous processing for an embodiment of the present disclosure. DETAILED DESCRIPTION

[0013] The present application describes a number of embodiments, but the description is exemplary rather than limiting and it will be apparent to those of ordinary skill in the art that numerous more embodiments and implementations are possible within the scope of the embodiments described in the present application. Although a number of possible combinations of features have been set forth in the accompanying figures and discussed above, many other combinations of the disclosed features are possible. Unless specifically intended otherwise, any feature or element of any embodiment can be used in combination with any other feature or element of any other embodiment, or in combination with any other feature or element of the same embodiment.

[0014] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application can also be combined with any conventional features or elements to form unique inventive solutions. Any feature or element of any embodiment can also be combined with features or elements from other inventive solutions to form another unique inventive solution. Therefore, it should be understood that any feature shown and / or discussed in the present application can be implemented alone or in any suitable combination. Accordingly, the embodiments are not to be restricted, except as by the appended claims and their equivalents. Furthermore, various modifications and changes can be made within the scope of the attached claims.

[0015] Moreover, in describing representative embodiments, the specification can have presented the method and / or process as a particular sequence of steps. However, to the extent that the method or process depends on the particular order of steps, the method or process should not be limited to the

[0016] Figure 1 A flowchart of the method for machining a thin-walled part according to an embodiment of the present disclosure is shown in FIG. 1, which includes the following steps: Figure 1 Step 101, identifying a maximum residual stress area in a blank before rough machining of a thin-walled part; Step 102, removing the identified maximum residual stress area to release residual stress in the maximum residual stress area; Step 103, preserving the deformation following the previous machining of the thin-walled part with released residual stress, and correcting the preserved deformation in the subsequent machining process by anti-deformation technology; wherein the subsequent machining includes rough machining and finish machining.

[0017] The embodiment of the present disclosure identifies the maximum residual stress area in the blank of the thin-walled part before rough machining, removes the identified maximum residual stress area by symmetry breaking method, realizes the early release of residual stress, can early induce the controllable deformation of the blank after the completion of rough machining, makes the deformation condition of the workpiece in the subsequent machining more predictable, realizes the effective control of the deformation of the workpiece, avoids the workpiece scrap due to the sudden deformation of the workpiece in the subsequent machining which cannot be corrected in time caused by improper stress release; after the effective release of residual stress, the deformation following the previous machining is preserved, and the anti-deformation technology is used to correct in the rough machining and finish machining stages, so that the blank releases deformation in the subsequent machining process, ensures the shape accuracy of the workpiece, reduces the scrap rate of the workpiece, reduces the material waste and reprocessing cost caused by the scrap of the workpiece, and improves the machining efficiency.

[0018] In an exemplary example, the embodiment of the present disclosure can be applied to large aluminum alloy thin-walled frames and other structural parts in aerospace equipment; the structural parts of aerospace equipment have the characteristics of thin wall, large size, low stiffness and complex structure, and the large thin-walled frame parts are prone to deformation after machining due to the redistribution of internal stress field of the blank.

[0019] ​In an example, the embodiment of the present disclosure identifies the maximum residual stress region in a thin-walled workpiece blank, comprising: The residual stress in the thin-walled workpiece blank is identified by the residual stress identification method to obtain the maximum residual stress region in the thin-walled workpiece blank.

[0020] The maximum residual stress region of the embodiment of the present disclosure can include the part of the workpiece that is most likely to cause maximum deformation.

[0021] In an example, the residual stress identification method in the embodiment of the present disclosure can include any one of the following methods: Finite element simulation method, residual stress measurement method and actual deformation back stress method.

[0022] The embodiment of the present disclosure can establish an accurate model of the blank and the machining process by means of finite element simulation method, simulate the change of stress and strain in the machining process, and thus intuitively identify the maximum residual stress region and stress concentration region. The embodiment of the present disclosure can also directly determine the residual stress size and direction at different positions of the blank by residual stress measurement technology, such as X-ray diffraction method or neutron diffraction method, to accurately locate the maximum residual stress region. The embodiment of the present disclosure can also observe the deformation of the workpiece of the previous machining scheme through devices including a three-coordinate machine, and through observation and analysis of the deformation of the workpiece using the previous machining scheme, according to the characteristics, position and degree of deformation and other information, the maximum residual stress region in the blank (the region in the workpiece that is easy to cause large deformation) is inferred reversely.

[0023] In an example, the embodiment of the present disclosure removes the identified maximum residual stress region, comprising: The identified maximum residual stress region is removed by a preset symmetry breaking method.

[0024] In an example, the symmetry breaking method in the embodiment of the present disclosure can include: Frame-by-frame removal method or layer-by-layer removal method.

[0025] The embodiment of the present disclosure can remove the symmetry breaking by one of the frame-by-frame removal method and the layer-by-layer removal method; the symmetry breaking method removes the material symmetrically to achieve deformation release; which method to use can be determined according to the actual situation of the machining site; compared with the related art of removing material layer by layer, the processing strategy of removing material symmetrically frame by frame can achieve better deformation effect; in this process, the center of mass of the blank and the residual stress distribution will change dramatically, thereby accelerating the release of deformation; it can more targetedly guide the release of residual stress, making the stress release more sufficient, and creating better conditions for subsequent machining.

[0026] In an exemplary instance, the symmetry breaking method of the embodiments of the present disclosure can be applied to a stage before rough machining of the thin-walled workpiece.

[0027] In an exemplary instance, the embodiments of the present disclosure can realize the processing of retaining the deformation of the thin-walled workpiece caused by the previous machining through the jig and / or the shim.

[0028] In some embodiments, the jig in the embodiments of the present disclosure can have anti-deformation properties, and the jig can be adjusted to follow the deformation of the workpiece, can better follow the deformation of the workpiece, facilitate the removal operation of the deformed part in the subsequent machining, and ensure the stability and machinability of the workpiece in the subsequent machining.

[0029] In some embodiments, the embodiments of the present disclosure can also add a shim between the jig and the gap of the workpiece to follow the deformation of the workpiece, which can effectively avoid introducing additional clamping deformation in the clamping process and facilitate the subsequent straightening work; the embodiments of the present disclosure make the correction of the deformation in the subsequent machining more easily through reasonable clamping and deformation retention measures, and since a certain machining allowance is still retained, the deformation can be effectively corrected, the deformation of the workpiece tends to be stable, the machining precision of the workpiece is improved, and the scrap rate of the workpiece machining is reduced.

[0030] The embodiments of the present disclosure also provide a computer storage medium, and the computer storage medium stores a computer program. The computer program is executed by a processor to realize the method for machining the thin-walled workpiece.

[0031] The embodiments of the present disclosure also provide a terminal, which comprises a memory and a processor. The memory stores a computer program. The processor is configured to execute the computer program in the memory. The computer program is executed by the processor to realize the method for machining the thin-walled workpiece.

[0032] Figure 2 The structural block diagram of the device for machining the thin-walled workpiece of the embodiments of the present disclosure is shown in Figure 2 The device comprises an identification unit, a removal unit and a deformation processing unit. The identification unit is configured to identify the maximum residual stress area in the thin-walled workpiece blank before rough machining. The removal unit is configured to remove the identified maximum residual stress area to release the residual stress of the maximum residual stress area. The deformation processing unit is configured to retain the deformation of the thin-walled workpiece caused by the previous machining after the residual stress is released, and correct the retained deformation through anti-deformation technology in the subsequent machining process. The subsequent machining comprises rough machining and finish machining.

[0033] In an exemplary instance, the identifying unit of the embodiment of the present disclosure is configured to: The residual stress in the thin-walled workpiece blank is identified by the residual stress identification method, so as to obtain the residual stress maximum region in the thin-walled workpiece blank.

[0034] In an exemplary instance, the residual stress identification method in the embodiment of the present disclosure can include any one of the following methods: The finite element simulation method, the residual stress measurement method and the actual deformation back-propagation stress method.

[0035] In an exemplary instance, the removing unit of the embodiment of the present disclosure is configured to: The identified residual stress maximum region is removed by using a preset symmetry breaking method.

[0036] In an exemplary instance, the symmetry breaking method in the embodiment of the present disclosure includes: Frame-by-frame removal method or layer-by-layer removal method.

[0037] In an exemplary instance, the deformation processing unit of the embodiment of the present disclosure is configured to retain the deformation caused by the previous processing for the thin-walled workpiece after the residual stress is released, including: The deformation caused by the previous processing is retained by releasing the residual stress of the thin-walled workpiece through the clamp and / or the cushion block.

[0038] The embodiment of the present disclosure is briefly described below through an application example. The application example is only used to describe the embodiment of the present disclosure, and does not limit the protection scope of the embodiment of the present disclosure.

[0039] The method of the embodiment of the present disclosure is applicable to workpieces of shapes including thin-walled, frame beam and skin, etc. The materials applicable to the method include aluminum alloy, steel, titanium alloy and composite material, etc. The machining machine tool applicable to the method includes three-axis numerical control machine tool or five-axis numerical control machine tool.

[0040] Figures 3 to 6 For the schematic diagram of removing the residual stress maximum region of the embodiment of the present disclosure, the embodiment of the present disclosure stimulates the residual stress release in advance by using the symmetry breaking method to control the deformation of the workpiece; see Figure 3 The workpiece to be processed 1 is placed on the machining platform; in order to stimulate the residual stress release in advance to control the deformation of the workpiece, see Figure 4 The operation of removing the material 2 of the workpiece in a symmetrical manner is performed; see Figure 5, by removing part of the material, the residual stress inside the blank is released, and the workpiece is deformed 3; in the process, according to the material, size and expected deformation effect of the blank, the position, size and depth of the symmetric breaking material removal 2 and other parameters are accurately controlled; for example, for metal blanks with specific residual stress distribution, appropriate material removal can be performed in the stress concentration area to promote early stress release and avoid uncontrollable deformation in subsequent processing; see Figure 6 Finally, after a series of subsequent straightening processes, the shaped workpiece 4 is obtained.

[0041] In an exemplary example, the residual stress identification step of the embodiments of the present disclosure uses identification methods including observation of the deformation of previously processed workpieces, finite element simulation methods, residual stress measurement methods, and actual deformation back-propagation stress methods; when observing the deformation of workpieces in the processing scheme of related technologies, the deformation of workpieces processed using related processing schemes can be analyzed to determine the deformation position and degree, and then the maximum residual stress area in the blank can be inferred; the finite element simulation method of the embodiments of the present disclosure uses related software to input parameters such as blank material properties, geometric shape, and processing technology to simulate the generation, distribution, and release of residual stress during processing. Residual stress measurement methods such as X-ray diffraction, drilling, contouring, and crack flexibility can be used to directly measure the blank to accurately determine the size and direction of the residual stress, so as to identify the part of the blank with larger residual stress or the part of the workpiece that is prone to cause larger deformation. Figure 7 The stress curve of the embodiments of the present disclosure is shown in FIG. 1, which uses the contouring method and simulation to obtain the stress curve, identifies the part of the blank with larger residual stress or the part of the workpiece that is prone to cause larger deformation by the stress size, and removes the part to stimulate the early release of residual stress. Figure 7

[0042] As shown in FIG. 2, the residual stress distribution of the blank is obtained by the simulation method, and the part of the blank with larger residual stress is identified by the stress size, and the part is removed to stimulate the early release of residual stress. Figure 8 and 9 ​As shown, the symmetry breaking excitation residual stress release of the embodiment of the present disclosure includes two ways of removing material layer by layer and removing material frame by frame; the embodiment of the present disclosure removing material layer by layer includes: according to a certain processing sequence, starting from the surface of the blank, removing the material 5 of each layer one by one; the thickness of each layer of material 5 removed needs to be determined according to factors such as processing accuracy and material properties; for example, for parts processing with high precision requirements, the thickness of each layer removed can be set smaller to ensure stability and accuracy during processing; in the process of removing material 5 layer by layer, the deformation of the blank is monitored in real time to adjust the processing parameters in time. The embodiment of the present disclosure removing material frame by frame includes: dividing the blank into multiple frame-shaped regions according to the shape of the blank and the processing requirements, and then removing the material 6 of the frame-shaped regions frame by frame according to a certain sequence; the way of removing material frame by frame can better control the change of the centroid of the blank and the release process of the residual stress; when removing material frame by frame, the size of the frame and the removal sequence need to be reasonably planned to achieve the best stress release and deformation control effect; for example, the frame-shaped material close to the edge of the blank and less affecting the overall structure can be removed first, and then gradually removed to the central area; from the perspective of stress release, frame-by-frame release can achieve more significant deformation effect than layer-by-layer release; in this process, the centroid of the blank and the distribution of residual stress will change dramatically, thereby accelerating the release of deformation. The embodiment of the present disclosure can more targetedly guide the release of residual stress, making the stress release more sufficient and uniform, and creating better conditions for subsequent processing.

[0043] When the embodiment of the present disclosure retains the deformation caused by the previous processing and corrects the retained deformation, the following workpiece deformation can be realized by two methods of clamps and pads. Figures 10 to 13 The principles of retaining deformation by clamps and pads are respectively shown; the clamp 7 is mainly used to follow the deformation of the blank 8 in the processing process; when the blank deforms in the processing process due to factors such as residual stress release, the clamp 7 can make corresponding adjustments through its own structural characteristics. In the embodiment of the present disclosure, when the deformed blank is corrected, the deformed blank is first stably clamped by the clamp 7; then, according to the specific situation of the deformation, the blank is corrected to remove material 9; the position and amount of the removed material need to be accurately calculated and determined according to the degree and direction of the deformation; after the material 9 is removed by correction, a workpiece 10 after correction is obtained, which meets the design size and shape requirements. In addition, more generally, the embodiment of the present disclosure can use pads 11, which can automatically adjust the position and shape according to the deformation of the blank, so as to tightly fit the surface of the deformed blank, and realize stable clamping of the blank. In the clamping process, the embodiment of the present disclosure avoids the additional deformation caused by the clamping of the traditional rigid clamp; compared with the pad, if the blank continues to deform in the subsequent processing process, the clamp 7 can continue to follow, ensuring the smooth progress of the processing.

[0044] The embodiments of the present disclosure achieve effective control of workpiece deformation, improve machining precision and product quality, and are suitable for machining of various types of blanks; in actual application, parameters and operation modes of each step can be flexibly adjusted according to different machining requirements and blank characteristics to achieve optimal machining effect.

[0045] Those skilled in the art can understand that all or some steps in the method disclosed above, and the functions of the functional modules / units in the system and the device can be implemented as software, firmware, hardware, and appropriate combinations thereof. In the hardware implementation, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be performed by several physical components in cooperation. Some or all of the components can be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on computer-readable media, which can include computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to those skilled in the art, the term "computer storage media" includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically includes computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism, and can include any information delivery media.

Claims

1. A method of machining a thin-walled piece, characterized in that, The method comprises the following steps: identifying a maximum residual stress area in a blank of a thin-walled part before rough machining; removing the identified maximum residual stress area to release residual stress of the maximum residual stress area; retaining deformation of the thin-walled part with released residual stress caused by previous machining and correcting the retained deformation through an anti-deformation technique in subsequent machining; wherein the subsequent machining comprises rough machining and finish machining.

2. The method of claim 1, wherein, The step of identifying the maximum residual stress area in the blank of the thin-walled part comprises: identifying residual stress in the blank of the thin-walled part through a residual stress identification method to obtain the maximum residual stress area in the blank of the thin-walled part.

3. The method of claim 2, wherein, The residual stress identification method can comprise any one of the following methods: a finite element simulation method, a residual stress measurement method and an actual deformation backstepping stress method.

4. The method of claim 1, wherein, The step of removing the identified maximum residual stress area comprises: removing the identified maximum residual stress area through a preset symmetry breaking method.

5. The method of claim 3, wherein, The symmetry breaking method comprises: a frame-by-frame removal method or a layer-by-layer removal method.

6. The method according to any one of claims 1 to 5, characterized in that, The step of retaining deformation of the thin-walled part with released residual stress caused by previous machining comprises: performing the processing of retaining deformation of the thin-walled part with released residual stress caused by previous machining through a jig and / or a cushion block. 7.A computer storage medium, wherein a computer program is stored in the computer storage medium, and the computer program is executed by a processor to implement the method for processing a thin-walled part according to any one of claims 1 to 6.

8. A terminal comprising: a memory and a processor, wherein the memory stores a computer program; and the processor is configured to execute the computer program in the memory; and the computer program is executed by the processor to implement the method for processing a thin-walled part according to any one of claims 1 to 6.

9. An apparatus for machining thin-walled parts, characterized in that The method comprises: an identifying unit, a removing unit and a deformation processing unit; wherein the identifying unit is configured to identify a maximum residual stress area in a blank of a thin-walled part before rough machining; the removing unit is configured to remove the identified maximum residual stress area to release residual stress of the maximum residual stress area; the deformation processing unit is configured to retain deformation of the thin-walled part with released residual stress caused by previous machining and correct the retained deformation through an anti-deformation technique in subsequent machining; wherein the subsequent machining comprises rough machining and finish machining.

10. The apparatus of claim 9, wherein, The identifying unit is configured to: identify residual stress in the blank of the thin-walled part through a residual stress identification method to obtain the maximum residual stress area in the blank of the thin-walled part.

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