A method and apparatus for laser shock forming of thin-walled structures

Abstract

The application provides a laser impact shaping method and device for a thin-walled structure, which comprises the following steps: obtaining a standard profile of a standard thin-walled structure and detecting an abnormal profile of a deformed thin-walled structure; setting an abnormal mark array on the surface of the deformed thin-walled structure, comparing the standard profile with the abnormal profile to determine a standard mark array; performing laser impact on the deformed thin-walled structure from the side of the deformed thin-walled structure which is concave inward, and detecting the abnormal distance between each abnormal mark in the abnormal mark array in real time; and stopping the laser impact on the deformed thin-walled structure when the error between the abnormal distance and the standard distance between each standard mark in the standard mark array is less than 1%. Through the application, the deformed thin-walled structure which is bent relative to the standard thin-walled structure is shaped.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser processing, in particular to a laser impact shaping method and device for thin-walled structural parts. BACKGROUND

[0002] In the reprocessing of thin-walled structural parts, internal stress may be generated due to various factors such as cutting force and clamping force. If not handled, these internal stresses may cause deformation or damage to the thin-walled structural parts in subsequent use. Therefore, the cutting performance of the thin-walled structural parts can be improved by shaping treatment, making them more stable during processing, and improving processing precision and surface quality.

[0003] Taking a titanium alloy aircraft panel as an example, the aircraft panel is generally processed into a certain curvature. Due to the difficulty in processing the titanium alloy aircraft panel, and the release of internal stress and other reasons during milling processing due to the removal of clamping force, the titanium alloy aircraft panel is usually excessively curved, resulting in a large dimensional error. Therefore, the excessively curved titanium alloy aircraft panel needs to be shaped. The conventional shaping method has unstable process, and may cause the titanium alloy aircraft panel to be scrapped in severe cases. Since the titanium alloy aircraft panel has high value, scrapping will cause significant economic loss.

[0004] Therefore, it is necessary to improve the existing thin-walled structural part shaping method to solve the above problems. SUMMARY

[0005] The present application aims to solve the problem that the titanium alloy aircraft panel is difficult to process, and is usually excessively curved due to the release of internal stress and other reasons during milling processing due to the removal of clamping force, resulting in a large dimensional error. The existing shaping method has an unstable process, and may cause the titanium alloy aircraft panel to be scrapped in severe cases, causing significant economic loss.

[0006] To achieve the above purpose, the present application provides a laser impact shaping method for thin-walled structural parts, which is used for shaping a deformed thin-walled structural part that is curved relative to a standard thin-walled structural part, comprising:

[0007] obtaining a standard profile of a standard thin-walled structural part, and detecting an abnormal profile of a deformed thin-walled structural part;

[0008] setting an abnormal marker array on the surface of the deformed thin-walled structural part, comparing the standard profile and the abnormal profile to determine a standard marker array;

[0009] performing laser impact on the deformed thin-walled structural part from the side of the deformed thin-walled structural part that is concave inward, and detecting the abnormal distance between each abnormal marker in the abnormal marker array in real time.

[0010] When the error between the abnormal distance and the standard distance between each standard mark in the standard mark array is less than 1%, stop laser impacting the deformed thin-walled structure.

[0011] As a further improvement of the present application, the laser impacting the deformed thin-walled structure from the side of the deformed thin-walled structure inwardly recessed comprises:

[0012] A constraint layer and an absorbing layer are sequentially arranged on the side of the deformed thin-walled structure inwardly recessed, and the absorbing layer is arranged between the constraint layer and the deformed thin-walled structure;

[0013] The focused laser beam irradiates the absorbing layer through the constraint layer from the side of the constraint layer away from the absorbing layer, so as to laser impact the deformed thin-walled structure.

[0014] As a further improvement of the present application, the pulse width of the laser beam is 10-30 ns, the wavelength is 532 nm or 1064 nm, and the power density is 3-7 GW / cm 2 The spot diameter of the focused laser beam is 3-5 mm.

[0015] As a further improvement of the present application, the absorbing layer is an aluminum foil with adhesive, the thickness of the aluminum foil is 100 microns, and the thickness of the adhesive is 10 microns.

[0016] As a further improvement of the present application, the constraint layer is a flowing water film, the thickness of the water film is 1-1.5 mm, and the flow rate of the water film is 5-10 cm / min.

[0017] As a further improvement of the present application, the material of the standard thin-walled structure and the deformed thin-walled structure is TC4 titanium alloy, and the thickness of the standard thin-walled structure and the deformed thin-walled structure is 2-4 mm.

[0018] As a further improvement of the present application, the diameter of the abnormal mark in the abnormal mark array is 0.1-0.3 mm, the distance between two adjacent abnormal marks is 0.6-1 mm, and the abnormal mark is an erasable mark and is sprayed on the surface of the deformed thin-walled structure through a mask.

[0019] Based on the same inventive idea, the present application also discloses a laser impact shaping device for thin-walled structures, which is used for shaping a deformed thin-walled structure bent relative to a standard thin-walled structure, and characterized in that it comprises:

[0020] A manipulator, a laser, and a camera;

[0021] acquire a standard profile of a standard thin-walled structure and detect an abnormal profile of a deformed thin-walled structure;

[0022] set an abnormal marker array on the surface of the deformed thin-walled structure, and compare the standard profile with the abnormal profile to determine a standard marker array;

[0023] The mechanical hand holds the deformed thin-walled structure and moves the deformed thin-walled structure to be coaxial with the laser and the camera;

[0024] The laser impacts the deformed thin-walled structure from the side of the deformed thin-walled structure that is inwardly recessed, and the camera detects the abnormal distance between each abnormal marker in the abnormal marker array in real time;

[0025] When the camera detects that the error between the abnormal distance and the standard distance between each standard marker in the standard marker array is less than 1%, stop the laser impact on the deformed thin-walled structure.

[0026] As a further improvement of the present application, the laser impact shaping device further comprises a control system that issues control instructions to the mechanical hand, the laser, and the camera.

[0027] As a further improvement of the present application, the laser impact shaping device further comprises a constraint layer and an absorption layer arranged on the side of the deformed thin-walled structure that is inwardly recessed, and the absorption layer is arranged between the constraint layer and the deformed thin-walled structure, and the focused laser beam irradiates the absorption layer through the constraint layer from the side of the constraint layer away from the absorption layer to impact the deformed thin-walled structure.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The laser impacts the deformed thin-walled structure from the side of the deformed thin-walled structure that is inwardly recessed, and the laser impact makes the treated surface of the deformed thin-walled structure obtain residual compressive stress, and then implements reverse deformation on the deformed thin-walled structure, thereby adjusting the bending degree of the deformed thin-walled structure, and by detecting the abnormal distance between each abnormal marker in the abnormal marker array in real time and comparing the abnormal distance with the standard distance, the size deviation between the adjusted bending degree of the deformed thin-walled structure and the standard thin-walled structure is detected, and when the deviation is less than 1%, the shaping of the deformed thin-walled structure is completed. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A step schematic diagram of a thin-walled structure laser impact shaping method shown in the present application;

[0031] Figure 2A schematic diagram of a step of laser impacting the deformed thin-walled structural member from the inwardly recessed side thereof;

[0032] Figure 3 A topology diagram of a laser impact reshaping device for a thin-walled structural member shown in the present application;

[0033] Figure 4 A schematic diagram of a deformed thin-walled structural member and a standard profile of a standard thin-walled structural member;

[0034] Figure 5 A schematic diagram of a deformed thin-walled structural member, a deformed marker array, and a standard marker array. DETAILED DESCRIPTION

[0035] The present application will be described in detail below with reference to the embodiments shown in the drawings, but it should be noted that these embodiments are not limiting of the present application, and equivalent transformations or substitutions of function, method, or structure made by those of ordinary skill in the art based on these embodiments are within the scope of the present application.

[0036] Please refer to Figures 1 to 5 The present application shows a specific embodiment of a laser impact reshaping method for a thin-walled structural member, which is used to reshape a deformed thin-walled structural member that is bent relative to a standard thin-walled structural member, and provides a stable reshaping method to solve the problem of large size error caused by excessive bending of the thin-walled structural member.

[0037] Please refer to Figure 1 A laser impact reshaping method for a thin-walled structural member includes the following steps S1 to S4.

[0038] Step S1, obtaining a standard profile of a standard thin-walled structural member, and detecting an abnormal profile of a deformed thin-walled structural member.

[0039] Step S2, setting an abnormal marker array on the surface of the deformed thin-walled structural member, comparing the standard profile and the abnormal profile to determine a standard marker array.

[0040] Step S3, laser impacting the deformed thin-walled structural member from the inwardly recessed side thereof, and detecting the abnormal distance between each abnormal marker in the abnormal marker array in real time.

[0041] Step S4, stopping the laser impact on the deformed thin-walled structural member when the error between the abnormal distance and the standard distance between each standard marker in the standard marker array is less than 1%.

[0042] Specifically, please refer to Figures 3 to 5As shown, the standard profile 43 of the standard thin-walled structure is obtained, and the deformed profile (not labeled) of the deformed thin-walled structure 4 is detected. The standard profile 43 refers to the profile formed by the side surface of the standard thin-walled structure, and the deformed profile refers to the profile formed by the side surface of the deformed thin-walled structure 4. When the array of abnormal marks 8 is subsequently arranged on the surface of the deformed thin-walled structure 4, the position of the array of standard marks 81 on the standard thin-walled structure can be determined by comparing the standard profile 43 with the deformed profile. The deformed thin-walled structure 4 is subjected to laser impact from the side of the deformed thin-walled structure 4 that is concave inward, and the abnormal distance between each abnormal mark 8 in the array of abnormal marks 8 is detected in real time. When the error between the abnormal distance and the distance between each standard mark 81 in the array of standard marks 81 is less than 1%, the laser impact on the deformed thin-walled structure 4 is stopped, thereby completing the shaping of the deformed thin-walled structure 4. The material of the standard thin-walled structure and the deformed thin-walled structure 4 is TC4 titanium alloy, and the thickness of the standard thin-walled structure and the deformed thin-walled structure 4 is 2-4 mm. The array of abnormal marks 8 refers to an array formed by a plurality of abnormal marks 8, and the shape of the abnormal mark 8 can be circular. The diameter of the abnormal mark 8 is 0.1-0.3 mm, and the distance between adjacent two abnormal marks is 0.6-1 mm. Preferably, the abnormal mark is an erasable mark, which can be sprayed on the surface of the deformed thin-walled structure 4 through a mask, and can be black ink.

[0043] It should be noted that the thin-walled structure is taken as an example of a titanium alloy aircraft panel. Generally, the standard thin-walled structure is curved to a certain extent. Due to the difficulty in processing the titanium alloy aircraft panel, and due to the release of internal stress and other reasons during the milling process, the titanium alloy aircraft panel is usually excessively curved, thereby forming the deformed thin-walled structure 4. In this application, the deformed thin-walled structure 4 is subjected to laser impact from the side of the deformed thin-walled structure 4 that is concave inward, so as to implement reverse deformation of the deformed thin-walled structure 4, thereby adjusting the degree of curvature of the deformed thin-walled structure 4. The abnormal distance between each abnormal mark 8 in the array of abnormal marks 8 is detected in real time, and the abnormal distance is compared with the standard distance, so as to detect the size deviation between the adjusted curvature of the deformed thin-walled structure 4 and the standard thin-walled structure. When the deviation is less than 1%, the laser impact on the deformed thin-walled structure 4 is stopped, thereby completing the shaping of the deformed thin-walled structure 4.

[0044] Reference Figure 2 As shown, the laser impact on the deformed thin-walled structure 4 from the side of the deformed thin-walled structure 4 that is concave inward includes the following steps S21-S22.

[0045] In step S21, a constraint layer and an absorption layer are sequentially arranged on the side of the deformed thin-walled structure that is concave inward.

[0046] Step S22: The focused laser beam passes through the constraint layer and irradiates the absorption layer on the side of the constraint layer opposite to the absorption layer, so as to perform laser shock on the deformed thin-walled structural component.

[0047] Specifically, both the constraint layer 2 and the absorption layer 3 are disposed on the inwardly recessed side of the deformable thin-walled structural member 4 (that is, Figure 3 The deformable thin-walled structure 4 shown is located on the left side, with an absorption layer 3 disposed between the constraint layer 2 and the deformable thin-walled structure 4. The constraint layer 2 is in contact with the absorption layer 3, and the absorption layer 3 is in contact with the surface 41 of the deformable thin-walled structure 4. A deformation mark 8 is disposed on the surface 42 of the deformable thin-walled structure 4. The focused laser beam 11 passes through the constraint layer 2 from the side of the constraint layer 2 away from the absorption layer 3 and irradiates the absorption layer 3 to perform laser shock on the deformable thin-walled structure 4. The pulse width of the laser beam 11 is 10~30ns, the wavelength is 532nm or 1064nm, and the power density is 3~7GW / cm². 2 The focused laser beam has a spot diameter of 3-5 mm. The absorption layer 3 is an aluminum foil with adhesive, the foil being 100 micrometers thick and the adhesive 10 micrometers thick. The constraint layer 2 is a flowing water film, 1-1.5 mm thick, with a flow rate of 5-10 cm / min. The laser impact path (which can also be understood as the movement path of the robotic arm 7 described below) can be determined by any method in the prior art; this embodiment does not specifically limit this.

[0048] It should be noted that, in this application, taking TC4 titanium alloy aircraft panels as an example, laser shock will cause residual compressive stress on the treated surface of the 2-4mm thick TC4 titanium alloy aircraft panels, causing the TC4 titanium alloy aircraft panels to deform in the reverse direction. This reverse deformation achieves the purpose of shaping the TC4 titanium alloy aircraft panels, thereby solving the problem of unstable process in existing shaping methods, which can lead to the scrapping of titanium alloy aircraft panels and significant economic losses in severe cases. At the same time, by real-time detection of the abnormal distance between each abnormal mark 8, the actual deviation between the abnormal contour after shaping and the standard contour 43 can be determined in real time, and the accuracy and quality of shaping can be precisely controlled, thereby ensuring the final shaping effect. In addition, residual stress can be obtained on both sides of the shaped TC4 titanium alloy aircraft panels, and the residual stress on the surface 42 of the shaped TC4 titanium alloy aircraft panels with abnormal marks 8 can be calculated by the abnormal distance between each abnormal mark 8. The shaped TC4 titanium alloy aircraft panels have excellent fatigue performance, and there is no need to perform secondary strengthening on the surface of the TC4 titanium alloy aircraft panels with abnormal marks 8.

[0049] Based on the foregoing embodiment of the laser shock shaping method of the thin-walled structural member, the present application also explains a laser shock shaping device of a thin-walled structural member, which is used for shaping a deformed thin-walled structural member 4 that is bent relative to a standard thin-walled structural member, and comprises a mechanical hand 7, a laser 1 and a camera 5.

[0050] Specifically, a standard profile 43 of the standard thin-walled structural member is acquired, and an abnormal profile of the deformed thin-walled structural member 4 is detected, an array of abnormal markers 8 is arranged on the surface of the deformed thin-walled structural member, and the standard profile 43 and the abnormal profile are compared based on this to determine an array of standard markers 81. The deformed thin-walled structural member 4 is clamped by the mechanical hand and is moved to be coaxial with the laser 1 and the camera 5, the laser 1 performs laser shock on the deformed thin-walled structural member 4 from the side of the deformed thin-walled structural member 4 that is inwardly recessed, and the surface 42 of the deformed thin-walled structural member 4 on which the array of abnormal markers 8 is arranged is photographed by the camera 5, and the abnormal distance between each abnormal marker 8 in the array of abnormal markers 8 is detected in real time, and when the camera 5 detects that the error of the abnormal distance and the standard distance between each standard marker 81 in the array of standard markers 81 is less than 1%, the laser shock on the deformed thin-walled structural member 4 is stopped, thereby completing the shaping of the deformed thin-walled structural member 4.

[0051] Preferably, the laser shock shaping device further comprises a control system 6 that issues control instructions to the mechanical hand 7, the laser 1 and the camera 5, the control system 6 clamps the deformed thin-walled structural member 4 by the mechanical hand 7 and moves it to be coaxial with the laser 1 and the camera 5, and always keeps the laser shock position coaxial with the laser 1 during the process that the laser beam 11 emitted by the laser 1 impacts the deformed thin-walled structural member 4; the control system 6 compares the standard profile 43 and the abnormal profile to determine the array of standard markers 81; and the control system acquires the process parameters of the laser shock and controls the laser 1 to emit the corresponding laser beam 11.

[0052] In an embodiment, the laser shock shaping device further comprises a constraint layer 2 arranged on the side of the deformed thin-walled structural member 4 that is inwardly recessed, and an absorbing layer 3 arranged between the constraint layer 2 and the deformed thin-walled structural member 4, and the focused laser beam 11 irradiates the absorbing layer 3 from the side of the constraint layer 2 that is away from the absorbing layer 3 through the constraint layer 2 to perform laser shock on the deformed thin-walled structural member 4. Embodiment

[0053] A laser shock strengthening method of a thin-walled structural member comprises:

[0054] The material of the deformed thin-walled structure 4 is TC4 titanium alloy, the thickness is 2mm, the local maximum deformation of the wall plate (i.e. the farthest distance between the abnormal profile and the standard profile 43) is 2.5mm; the pulse width of the laser beam 11 emitted by the laser 1 is 10ns, the power density is 7GW / cm 2 , the spot diameter of the focused laser beam 11 is 3mm; the absorption layer 3 is an aluminum foil with adhesive, the thickness of the aluminum foil is 100 microns, and the thickness of the adhesive is 10 microns; the constraint layer 2 is a flowing water film, the thickness is about 1mm, and the flow rate is 5cm / min; the diameter of the abnormal mark 8 is 0.1mm, and the distance between the abnormal marks 8 is 0.6mm. The deformed thin-walled structure 4 is reshaped by the laser shock peening method shown in the application, and the local maximum deformation of the reshaped deformed thin-walled structure 4 is 0.3mm. Through XRD test, the average residual compressive stress value of the inwardly concave side of the reshaped deformed thin-walled structure 4 is 163MPa, and the average residual compressive stress value of the outwardly protruding side of the reshaped deformed thin-walled structure 4 is 137MPa. Embodiment

[0055] A laser shock peening method for a thin-walled structure includes:

[0056] The material of the deformed thin-walled structure 4 is TC4 titanium alloy, the thickness is 4mm, the local maximum deformation of the wall plate (i.e. the farthest distance between the abnormal profile and the standard profile 43) is 3mm; the pulse width of the laser beam 11 emitted by the laser 1 is 30ns, the power density is 3GW / cm 2 , the spot diameter of the focused laser beam 11 is 5mm; the absorption layer 3 is an aluminum foil with adhesive, the thickness of the aluminum foil is 100 microns, and the thickness of the adhesive is 10 microns; the constraint layer 2 is a flowing water film, the thickness is about 1.5mm, and the flow rate is 10cm / min; the diameter of the abnormal mark 8 is 0.3mm, and the distance between the abnormal marks 8 is 1mm. The deformed thin-walled structure 4 is reshaped by the laser shock peening method shown in the application, and the local maximum deformation of the reshaped deformed thin-walled structure 4 is 0.26mm. Through XRD test, the average residual compressive stress value of the inwardly concave side of the reshaped deformed thin-walled structure 4 is 219MPa, and the average residual compressive stress value of the outwardly protruding side of the reshaped deformed thin-walled structure 4 is 188MPa.

[0057] The above series of detailed descriptions are only specific descriptions of the feasible embodiments of the application, and are not intended to limit the protection scope of the application. Any equivalent embodiments or changes made without departing from the spirit of the application should be included in the protection scope of the application.

[0058] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0059] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A laser shock stabilization method for thin-walled structural components, used to shape deformed thin-walled structural components that are bent relative to standard thin-walled structural components, characterized in that, include: Obtain the standard profile of a standard thin-walled structural component and detect the abnormal profile of a deformed thin-walled structural component; An abnormal marker array is set on the surface of the deformable thin-walled structural member, and the standard contour and the abnormal contour are compared to determine the standard marker array; Laser shock is applied to the deformable thin-walled structure from the inwardly recessed side, and the abnormal distance between each abnormal marker in the abnormal marker array is detected in real time. When the error between the abnormal distance and the standard distance between each standard mark in the standard mark array is less than 1%, the laser impact on the deformed thin-walled structure is stopped.

2. The laser shock shaping method according to claim 1, characterized in that, The laser impact on the deformable thin-walled structure from the inwardly recessed side includes: A constraint layer and an absorption layer that axially cover the deformable thin-walled structure are sequentially provided on the inwardly recessed side of the deformable thin-walled structure, and the absorption layer is disposed between the constraint layer and the deformable thin-walled structure. The focused laser beam passes through the constraint layer on the side of the constraint layer opposite to the absorption layer and irradiates the absorption layer to perform laser shock on the deformable thin-walled structure.

3. The laser shock shaping method according to claim 2, characterized in that, The laser beam has a pulse width of 10–30 ns, a wavelength of 532 nm or 1064 nm, and a power density of 3–7 GW / cm². 2 The diameter of the focused laser beam is 3-5 mm.

4. The laser shock shaping method according to claim 2, characterized in that, The absorbent layer is an aluminum foil with adhesive, the aluminum foil having a thickness of 100 micrometers and the adhesive having a thickness of 10 micrometers.

5. The laser shock shaping method according to claim 2, characterized in that, The constraint layer is a flowing water film with a thickness of 1 to 1.5 mm and a flow rate of 5 to 10 cm / min.

6. The laser shock shaping method according to claim 1, characterized in that, Both the standard thin-walled structural component and the deformed thin-walled structural component are made of TC4 titanium alloy, and both have a thickness of 2-4 mm.

7. The laser shock shaping method according to claim 1, characterized in that, The diameter of the abnormal markers in the abnormal marker array is 0.1 to 0.3 mm, the distance between two adjacent abnormal markers is 0.6 to 1 mm, and the abnormal markers are erasable markers, which are sprayed onto the surface of the deformable thin-walled structure through a mask.

8. A laser shock sculpting apparatus for thin-walled structural components, used to shape deformed thin-walled structural components that are bent relative to standard thin-walled structural components, characterized in that, include: robotic arms, lasers, and cameras; Obtain the standard profile of a standard thin-walled structural component and detect the abnormal profile of a deformed thin-walled structural component; An abnormal marker array is set on the surface of the deformable thin-walled structural member, and the standard contour and the abnormal contour are compared to determine the standard marker array; The robotic arm grips the deformable thin-walled structure and moves it to be coaxial with the laser and the camera. The laser impacts the deformable thin-walled structure from the inwardly recessed side, and the camera detects the abnormal distance between each abnormal marker in the abnormal marker array in real time. When the camera detects that the error between the abnormal distance and the standard distance between each standard mark in the standard mark array is less than 1%, the laser impact on the deformable thin-walled structure is stopped.

9. The laser shock shaping device according to claim 8, characterized in that, The laser shock shaping device also includes a control system that sends control commands to the robotic arm, the laser, and the camera.

10. The laser shock shaping device according to claim 9, characterized in that, The laser shock shaping device further includes a constraint layer and an absorption layer disposed on the inwardly recessed side of the deformed thin-walled structure, wherein the absorption layer is disposed between the constraint layer and the deformed thin-walled structure, and the focused laser beam passes through the constraint layer on the side of the constraint layer opposite to the absorption layer to irradiate the absorption layer, thereby performing laser shock on the deformed thin-walled structure.

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