Laser ultrasonic stress detection equipment

Abstract

The utility model relates to the technical field of residual stress detection, in particular to laser ultrasonic stress detection equipment which comprises a workbench, and the workbench is provided with a mechanical arm, a laser used for emitting excitation laser, a light guide arm and a laser ultrasonic detection head used for conducting residual stress detection on a workpiece. The laser ultrasonic detection head is fixed at the free end of the mechanical arm, a light inlet of the light guide arm is communicated with a light emitting port of the laser, and a light outlet of the light guide arm is communicated with a light inlet of the laser ultrasonic detection head. The mechanical arm and the light guide arm are additionally arranged, the mechanical arm and the light guide arm are matched to realize free movement of the laser ultrasonic detection head in a three-dimensional space, the degree of freedom of the laser ultrasonic detection head is improved, the possibility that the laser ultrasonic detection head has detection dead angles is reduced, and the positioning precision of the laser ultrasonic detection head is improved.

Description

Technical Field

[0001] The present application relates to the technical field of residual stress detection, and in particular to a laser ultrasonic stress detection device. Background Art

[0002] In mechanical processing, the generation of residual stress is inevitable. The influence of residual tensile stress in components usually shows harmful effects, such as reducing the fatigue strength of components, causing stress corrosion and brittle fracture, and reducing the dimensional accuracy of components. In engineering, people often only pay attention to the working stress, while ignoring the residual stress in the workpiece. In metal corrosion cracking accidents, residual stress often plays an important role. Therefore, it is particularly important to detect residual stress in components.

[0003] Laser ultrasound uses pulsed laser to irradiate the surface of solid materials. Due to the local high temperature generated on the irradiated area, a thermal elastic and ablation mechanism is formed, which in turn stimulates ultrasonic waves, and then a laser interferometer is used to receive the ultrasonic waves for residual stress detection. The detection head in the existing laser ultrasonic stress detection equipment has a low degree of freedom. When the workpiece is fixed, the detection head has a blind spot for detection, which has great limitations and needs further improvement. Utility Model Content

[0004] In order to reduce the possibility of detection blind spots in the detection head, the present application provides a laser ultrasonic stress detection device.

[0005] The laser ultrasonic stress detection device provided in this application adopts the following technical solution:

[0006] A laser ultrasonic stress detection device comprises a workbench, wherein the workbench is provided with a mechanical arm, a laser, a light guide arm and a laser ultrasonic detection head for performing residual stress detection on a workpiece, the laser ultrasonic detection head is fixed to the free end of the mechanical arm, the light inlet of the light guide arm is connected to the light emitting port of the laser, and the light outlet of the light guide arm is connected to the light inlet of the laser ultrasonic detection head.

[0007] By adopting the above technical solution, a mechanical arm and a light guide arm are added. The mechanical arm and the light guide arm cooperate with each other to realize the free movement of the laser ultrasonic detection head in three-dimensional space, thereby improving the degree of freedom of the laser ultrasonic detection head, reducing the possibility of blind angle detection of the laser ultrasonic detection head, and improving the positioning accuracy of the laser ultrasonic detection head.

[0008] Preferably, the laser ultrasonic detection head includes a detection shell and a laser interferometer built into the detection shell for emitting and receiving lasers. The detection shell is equipped with a first reflector for receiving the excitation laser emitted by the light guide arm. An excitation laser window and a receiving laser window are provided on the same side wall of the detection shell. The excitation laser reflected by the first reflector is emitted from the excitation laser window, and the receiving laser is emitted from the receiving laser window.

[0009] By adopting the above technical solution, the excitation laser emitted from the light outlet of the light guide arm is directly irradiated to the first reflector, and the excitation laser after being reflected by the first reflector is emitted from the excitation laser window and irradiated to the surface of the workpiece, and the receiving laser emitted by the laser interferometer is emitted from the receiving laser window and irradiated to the surface of the workpiece to perform residual stress detection on the workpiece.

[0010] Preferably, the detection housing is provided with a light-transmitting window mirror for sealing the excitation laser window and the receiving laser window.

[0011] By adopting the above technical solution and adding a light-transmitting window mirror, the possibility of dust entering the detection shell from the excitation laser window and the receiving laser window and causing contamination to the parts inside the detection shell is effectively reduced.

[0012] Preferably, the laser ultrasonic detection head also includes a galvanometer built into the detection shell, and the excitation laser reflected by the first reflector is emitted into the light inlet of the galvanometer. The detection shell is equipped with a second reflector for receiving the excitation laser emitted from the light outlet of the galvanometer, and the excitation laser reflected by the second reflector is emitted from the excitation laser window.

[0013] By adopting the above technical solution, the excitation laser emitted from the light outlet of the light guide arm is directly emitted to the first reflector, and enters the galvanometer after being reflected by the first reflector. The coordinate position of the excitation laser is adjusted by the galvanometer and then emitted to the second reflector. The excitation laser reflected by the second reflector is emitted from the excitation laser window.

[0014] Preferably, a cylindrical mirror is arranged between the light inlet of the galvanometer and the first reflector, and the excitation laser reflected by the second reflector penetrates the cylindrical mirror.

[0015] By adopting the above technical solution, a cylindrical mirror is additionally provided, and the cylindrical mirror modulates the excitation laser into a line source, thereby improving the radiation efficiency of the excitation laser surface wave.

[0016] Preferably, a DOE lens for the excitation laser to pass through is provided between the light inlet of the galvanometer and the first reflector.

[0017] By adopting the above technical solution, a DOE lens is additionally provided, and the DOE lens modulates the excitation laser so that the excitation laser can generate surface waves of different frequencies.

[0018] Preferably, a depth switching assembly is arranged between the light inlet of the galvanometer and the first reflector, and the depth switching assembly includes a switching frame built into the detection shell and located between the light inlet of the galvanometer and the first reflector, a turntable rotatably connected to the switching frame, and a driving member driving the turntable to rotate around its own axis, the turntable is provided with a light opening along the axial direction, and a plurality of light openings are arranged and distributed around the axis of the turntable, and a plurality of DOE lenses are correspondingly arranged and cover the light openings, and the structures of the plurality of DOE lenses are different, and the axis of one of the light openings coincides with the axis of the light inlet of the galvanometer.

[0019] By adopting the above technical solution, the turntable is driven to rotate around its own axis by the driving member, so that the position of the DOE lens on the turntable is switched to modulate the excitation laser to generate surface waves of different frequencies, thereby testing the residual stress values ​​of different depths of the workpiece.

[0020] Preferably, the driving member is a stepper motor fixedly connected to the switching frame, and the output shaft of the stepper motor is coaxially fixedly connected to the turntable.

[0021] By adopting the above technical solution, the rotation angle of the turntable can be accurately adjusted by the stepping motor.

[0022] Preferably, the outer side wall of the workbench is provided with a hanging ring.

[0023] By adopting the above technical solution, a lifting ring is additionally provided to facilitate the lifting operation of the workbench.

[0024] Preferably, it further comprises a control panel located at one side of the workbench, the control panel is provided with a display for displaying the detection data of the laser ultrasonic detection head, and the control panel is detachably connected to the workbench through a connecting component.

[0025] By adopting the above technical solution, the control panel and the workbench are detachably connected via a connecting assembly, which facilitates the fixing and separation of the control panel and the workbench according to different working conditions.

[0026] In summary, the utility model has the following beneficial effects:

[0027] 1. Add a mechanical arm and a light guide arm. The mechanical arm and the light guide arm cooperate to realize the free movement of the laser ultrasonic detection head in three-dimensional space, improve the degree of freedom of the laser ultrasonic detection head, reduce the possibility of the laser ultrasonic detection head having a blind spot, and improve the positioning accuracy of the laser ultrasonic detection head;

[0028] 2. A light-transmitting window mirror is added to effectively reduce the possibility of dust entering the detection housing from the excitation laser window and the receiving laser window and causing pollution to the parts inside the detection housing;

[0029] 3. A DOE lens is added to eliminate the ripples of the excitation laser and improve the beam quality of the excitation laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the overall structure of a laser ultrasonic stress detection device in Example 1;

[0031] Figure 2 is a schematic diagram of the connection structure between the workbench and the control console in Example 1;

[0032] Figure 3 is a schematic diagram of the internal structure of the detection housing in Example 1;

[0033] Figure 4 is a schematic diagram of the detection optical path of the laser ultrasonic detection head in Example 1;

[0034] Figure 5 is a schematic diagram of the internal structure of the detection housing in Example 2;

[0035] Figure 6 It is a schematic diagram of the installation structure of the DOE lens in Example 2.

[0036] In the figure, 10, workbench; 101, moving wheel; 102, lifting ring; 20, control panel; 201, display; 30, connecting component; 301, connecting plate; 302, connecting seat; 1, mechanical arm; 2, laser; 3, light guide arm; 4, laser ultrasonic detection head; 41, detection shell; 411, installation port; 412, excitation laser window; 413, receiving laser window; 414, shooting port; 42, laser interferometer; 43, galvanometer; 44, first reflector; 45, DOE lens; 46, cylindrical mirror; 47, second reflector; 48, light-transmitting window mirror; 49, camera; 5, depth switching component; 51, switching frame; 52, turntable; 53, stepping motor; 54, light port. DETAILED DESCRIPTION

[0037] The following is combined with Figure 1-6 This application is described in further detail.

[0038] Embodiment 1:

[0039] The present application discloses a laser ultrasonic stress detection device, referring to Figure 1 , including a workbench 10 and a control panel 20 located on one side of the workbench 10 , the lower end surfaces of the workbench 10 and the control panel 20 are rotatably connected with moving wheels 101 , and the outer side wall of the workbench 10 is provided with a hanging ring 102 .

[0040] Reference Figure 1 , Figure 2The control panel 20 is detachably connected to the workbench 10 through the connection assembly 30. In this embodiment, the upper end surface of the control panel 20 is higher than the upper end surface of the workbench 10. The connection assembly 30 includes a connection plate 301 located below the workbench 10 and the control panel and a connection seat 302 arranged on one side of the upper end surface of the workbench 10. The upper end surface of the connection plate 301 abuts against the lower end surfaces of the workbench 10 and the control panel 20. Both ends of the connection plate 301 are bolted to the lower end surfaces of the workbench 10 and the control panel 20. The lower end surface of the connection seat 302 abuts against the upper end surface of the workbench 10, and one side of the connection seat 302 abuts against the side wall of the control panel 20. The connection seat 302 is bolted to the workbench 10 and the control panel 20.

[0041] The workbench 10 is provided with a mechanical arm 1, a laser 2 for emitting an excitation laser, and a laser ultrasonic detection head 4 for detecting residual stress of a workpiece. The base of the mechanical arm 1 is fixedly connected to the upper end surface of the workbench 10. The laser 2 is a pulse laser 2. The laser 2 is fixedly connected to the upper end surface of the workbench 10 and is located on one side of the mechanical arm 1. The laser ultrasonic detection head 4 is installed at the free end of the mechanical arm 1. A light guide arm 3 is provided between the laser 2 and the laser ultrasonic detection head 4 for guiding the excitation laser emitted by the laser 2 to the laser ultrasonic detection head 4. The light guide arm 3 is used in conjunction with the mechanical arm 1. The light guide arm 3 can cooperate with the movement of the mechanical arm 1. The light inlet of the light guide arm 3 is connected to the light emitting port of the laser 2, and the light outlet of the light guide arm 3 is connected to the light inlet of the laser ultrasonic detection head 4.

[0042] Reference Figure 1 , Figure 3 In this embodiment, the laser ultrasonic detection head 4 includes a detection housing 41, a laser interferometer 42 built into the detection housing 41 for transmitting and receiving lasers, and a galvanometer 43 built into the detection housing 41. The detection housing 41 is fixedly connected to the free end of the robot arm 1. The side wall of the detection housing 41 is provided with a mounting opening 411 for the light outlet end of the light guide arm 3 to pass through. The inner wall of the detection housing 41 is provided with a first reflector 44, a DOE lens 45, a cylindrical mirror 46 and a second reflector 47. The first reflector 44 is located on the side opposite to the light inlet of the galvanometer 43, and the DOE lens 45 is located between the first reflector 44 and the light inlet of the galvanometer 43. In this embodiment, the axis of the DOE lens 45 coincides with the axis of the light inlet of the galvanometer 43.

[0043] Reference Figure 3 , Figure 4, the cylindrical mirror 46 is located between the DOE lens 45 and the light inlet of the galvanometer mirror 43, the second reflector 47 is located on the side opposite to the light outlet of the galvanometer mirror 43, the same side wall of the detection housing 41 is provided with an excitation laser window 412, a receiving laser window 413 and a shooting port 414 located below the excitation laser window 412, and the detection housing 41 is provided with a light-transmitting window mirror 48 for blocking the excitation laser window 412 and the receiving laser window 413. The excitation laser emitted by the laser 2 enters the inner cavity of the detection housing 41 through the conduction of the light guide arm 3, and then directly hits the first reflector 44, and then reflects through the DOE lens 45 and the cylindrical mirror 46 in turn and hits the galvanometer mirror 43, and then hits the second reflector 47 after the galvanometer mirror 43 adjusts the position of the excitation laser, and then hits the second reflector 47, and the excitation laser reflected by the second reflector 47 is irradiated to the surface of the workpiece through the light-transmitting window mirror 48 on the excitation laser window 412, and the detection housing 41 is built with a camera 49 for shooting the irradiation position of the excitation laser, and the camera 49 is an industrial camera. The receiving laser emitted by the laser interferometer 42 is irradiated onto the surface of the workpiece through the transparent window mirror 48 on the transparent receiving laser window 413 to perform ultrasonic detection operations. The control console 20 is provided with a display 201 for displaying the detection data of the laser ultrasonic detection head 4. The control console 20 calculates the residual stress on the surface of the workpiece by combining the ultrasonic waves detected by the laser ultrasonic detection head 4 with the acoustic elasticity principle.

[0044] The implementation principle of a laser ultrasonic stress detection device in an embodiment of the present application is: the mechanical arm 1 and the light guide arm 3 cooperate to realize the free movement of the laser ultrasonic detection head 4 in three-dimensional space, improve the degree of freedom of the laser ultrasonic detection head 4, reduce the possibility of detection blind spots of the laser ultrasonic detection head 4, and improve the positioning accuracy of the laser ultrasonic detection head 4.

[0045] When residual stress detection is required for a higher workpiece, unlock the connecting plate 301 and the connecting seat 302 to release the fixed restrictions of the workbench 10 and the control console 20, tie the lifting rope to the lifting ring 102, and use the lifting equipment to lift the workbench 10 through the lifting rope to perform residual stress detection on a higher position of the workpiece.

[0046] Embodiment 2:

[0047] The difference from Example 1 is that, referring to Figure 5 , Figure 6A depth switching assembly 5 is provided between the cylindrical mirror 46 and the first reflector 44. The depth switching assembly 5 includes a switching frame 51, a turntable 52 and a driving member. The switching frame 51 is built into the detection housing 41 and is located between the cylindrical mirror 46 and the first reflector 44. The turntable 52 is connected to the switching frame 51 by rotating around its own axis. The driving member is a stepper motor 53. The stepper motor 53 is fixedly connected to the switching frame 51. The output shaft of the stepper motor 53 is coaxially fixedly connected to the turntable 52. The turntable 52 is provided with a light opening 54 along the axial direction. There are multiple light openings 54 and they are distributed around the axis of the turntable 52. There are multiple DOE lenses 45 correspondingly provided and covering the light openings 54. The structures of the multiple DOE lenses 45 are different. The axis of one of the light openings 54 coincides with the axis of the light inlet of the galvanometer 43.

[0048] When it is necessary to detect the residual stress at different depths of the workpiece, the stepper motor 53 is started to drive the turntable 52 to rotate, so that the corresponding DOE lens 45 rotates and switches to the detection position (the position coincident with the axis of the light inlet of the galvanometer 43).

[0049] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A laser ultrasonic stress detection device, characterized in that: The workbench (10) comprises a mechanical arm (1), a laser (2) for emitting an excitation laser, a light guide arm (3), and a laser ultrasonic detection head (4) for detecting residual stress of a workpiece, wherein the laser ultrasonic detection head (4) is fixed to the free end of the mechanical arm (1), the light inlet of the light guide arm (3) is connected to the light emitting port of the laser (2), and the light outlet of the light guide arm (3) is connected to the light inlet of the laser ultrasonic detection head (4).

2. The laser ultrasonic stress detection device according to claim 1, characterized in that: The laser ultrasonic detection head (4) comprises a detection housing (41) and a laser interferometer (42) built into the detection housing (41) for emitting and receiving laser light. The detection housing (41) is built with a first reflector (44) for receiving an excitation laser light emitted by a light guide arm (3). An excitation laser window (412) and a receiving laser window (413) are provided on the same side wall of the detection housing (41). The excitation laser light reflected by the first reflector (44) is emitted from the excitation laser window (412), and the receiving laser light is emitted from the receiving laser window (413).

3. The laser ultrasonic stress detection device according to claim 2, characterized in that: The detection housing (41) is provided with a light-transmitting window mirror (48) for sealing the excitation laser window (412) and the receiving laser window (413).

4. The laser ultrasonic stress detection device according to claim 2, characterized in that: The laser ultrasonic detection head (4) further comprises a galvanometer (43) built into the detection housing (41); the excitation laser reflected by the first reflector (44) is emitted into the light inlet of the galvanometer (43); the detection housing (41) is built with a second reflector (47) for receiving the excitation laser emitted from the light outlet of the galvanometer (43); the excitation laser reflected by the second reflector (47) is emitted from the excitation laser window (412).

5. The laser ultrasonic stress detection device according to claim 4, characterized in that: A cylindrical mirror (46) is provided between the light inlet of the galvanometer mirror (43) and the first reflector (44), and the excitation laser reflected by the second reflector (47) penetrates the cylindrical mirror (46).

6. The laser ultrasonic stress detection device according to claim 4, characterized in that: A DOE lens (45) for the excitation laser to pass through is arranged between the light inlet of the galvanometer (43) and the first reflector (44).

7. The laser ultrasonic stress detection device according to claim 6, characterized in that: A depth switching assembly (5) is arranged between the light inlet of the galvanometer (43) and the first reflector (44), and the depth switching assembly (5) comprises a switching frame (51) built into the detection housing (41) and located between the light inlet of the galvanometer (43) and the first reflector (44), a turntable (52) rotatably connected to the switching frame (51), and a driving member driving the turntable (52) to rotate around its own axis, the turntable (52) being provided with a light through hole (54) along the axial direction, a plurality of light through holes (54) being arranged and distributed around the axis of the turntable (52), a plurality of DOE lenses (45) being arranged correspondingly and covering the light through holes (54), the structures of the plurality of DOE lenses (45) being different, and the axis of one of the light through holes (54) being coincident with the axis of the light inlet of the galvanometer (43).

8. The laser ultrasonic stress detection device according to claim 7, characterized in that: The driving member is a stepping motor (53) fixedly connected to the switching frame (51), and the output shaft of the stepping motor (53) is coaxially fixedly connected to the rotating disk (52).

9. The laser ultrasonic stress detection device according to claim 1, characterized in that: The outer side wall of the workbench (10) is provided with a hanging ring (102).

10. The laser ultrasonic stress detection device according to claim 1, characterized in that: It also includes a control panel (20) located on one side of the workbench (10), the control panel (20) being provided with a display (201) for displaying detection data of the laser ultrasonic detection head (4), and the control panel (20) being detachably connected to the workbench (10) via a connection assembly (30).

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