A device and method for real-time surface defect detection of friction stir welding of an automobile component

Abstract

The application discloses a kind of real-time surface defect detection device and method of automobile parts friction stir welding, including friction welding component limiting platform, for fixing the measured friction welding component, the measured surface of measured friction welding component has side-by-side first welding edge and second welding edge;Polarized imaging component and polarized light source are relatively displaced in the length direction of first welding edge and second welding edge;Polarized imaging component includes first polarized imaging component and second polarized imaging component;Polarized light source includes first polarized light source and second polarized light source, which simultaneously irradiate first welding edge and second welding edge, the polarization direction of first polarized light source and first polarized imaging component is perpendicular to the light source polarization direction of second polarized light source and second polarized imaging component.The application effectively solves the shortcoming that simple photometric stereo method cannot realize edge moving while photographing, and also solves the defect that simple binocular camera cannot realize defect information strengthening.

Description

Technical Field

[0001] This invention relates to the field of welding inspection, specifically to a device and method for real-time surface defect detection of friction stir welding of automotive parts. Background Technology

[0002] Friction stir welding (FSW) utilizes the heat generated by the friction between a high-speed rotating welding tool and the workpiece to locally melt the materials being welded. As the welding tool moves forward along the welding interface, the plasticized material flows from the front to the rear of the tool under the rotational friction force, forming a dense solid-phase weld under the pressure of the tool. FSW has advantages such as minimal microstructural changes in the heat-affected zone, relatively low residual stress, and resistance to workpiece deformation. Therefore, it is often used for welding thin-walled parts, such as the cooling water jackets and motor housings of new energy vehicle motors. Currently, surface defects in FSW are mainly concentrated on both sides of the weld, including burrs, keyholes, surface depressions, and furrows. These defects are currently mainly identified visually, but the weld is often very small, making it easy to miss them visually. Currently, for visual analysis, line structured light sensors can be used to scan along the weld seam to obtain point cloud information of the friction stir weld surface and analyze the aforementioned surface defects. Although this method is relatively mature, the cost of a single line structured light sensor is currently high, generally more than ten times that of a typical industrial camera. Therefore, this limits the application of this technology.

[0003] In addition, conventional 2D industrial cameras are not sensitive to defects with surface height differences (flash, keyholes, surface depressions, burrs, and furrows) when used for inspection. In special cases, surface defects may not be identifiable by visual inspection of the captured images.

[0004] However, if the photometric stereo method is used, such as the invention application with publication number CN 112129764 A entitled "Polarized Light Source, Surface Defect Detection Method and Apparatus", it adopts the photometric stereo method. Although this method is highly sensitive to defects with surface height differences, it requires multiple images to be collected at the same location and matched. Since the surface defects of friction stir welding need to be detected in real time, it means that the imaging component is in a real-time moving state, so it cannot meet the requirement of "the same location".

[0005] The aforementioned 2D industrial cameras and photometric stereo methods both suffer from difficulties in dimensional measurement. While multi-view cameras now have dimensional measurement capabilities, they lack sensitivity to height difference defects, and the acquired images may contain unclear defect information.

[0006] Based on this requirement, a device based on multi-view vision technology, polarized light technology, and photometric stereo method is needed to achieve real-time detection of the absence of the surface in friction stir welding. Summary of the Invention

[0007] This invention provides a real-time surface defect detection device and method for friction stir welding of automotive parts. It combines the advantages of photometric stereo method, binocular vision method, and polarization vision technology, while also complementing each other's shortcomings. It effectively solves the problem that the simple photometric stereo method cannot achieve simultaneous moving and taking pictures, and also solves the problem that the simple binocular camera cannot enhance the defect information.

[0008] To achieve the above objectives, in a first aspect, the present invention provides the following technical solution: a real-time surface defect detection device for friction stir welding of automotive parts, comprising a friction stir welding component limiting platform for fixing the friction stir welding component to be tested, wherein the surface of the friction stir welding component to be tested has a first welding edge and a second welding edge arranged side by side, and there is no relative movement between the friction stir welding component limiting platform and the friction stir welding component to be tested, wherein the first welding edge and the second welding edge are the two sides of the weld left after friction stir welding, which are the locations where surface defects occur;

[0009] The polarization imaging component and polarization light source are set on one side of the friction welding component limiting platform and are relatively displaced along the length of the first welding edge and the second welding edge. During detection, the polarization imaging component and polarization light source can move relative to the friction welding component limiting platform to realize real-time detection of surface defects in friction stir welding.

[0010] The polarization imaging component includes a first polarization imaging component and a second polarization imaging component. The first polarization imaging component and the second polarization imaging component are arranged side by side at positions corresponding to the first welding edge and the second welding edge, respectively. The imaging of the first polarization imaging component and the second polarization imaging component can cover the first welding edge and the second welding edge. The first polarization imaging component and the second polarization imaging component take pictures of the first welding edge and the second welding edge in real time to acquire images, thereby realizing the binocular vision method.

[0011] The polarization light source includes a first polarization light source and a second polarization light source. The first polarization light source is located on the side of the second polarization imaging component away from the first polarization imaging component, and the second polarization light source is located on the side of the first polarization imaging component away from the second polarization imaging component. The first polarization light source and the second polarization light source simultaneously illuminate the first welding edge and the second welding edge. The function of the first polarization light source and the second polarization light source is to allow surface defects at the first welding edge and the second welding edge to produce shadows, and at the same time, to make the imaging of the first polarization imaging component and the second polarization imaging component clearer.

[0012] The first polarization light source and the first polarization imaging component have the same polarization direction, which is the first polarization direction. The second polarization light source and the second polarization imaging component have the same polarization direction, which is the second polarization direction. The first polarization direction and the second polarization direction are perpendicular to each other. By using polarized light, the shadows generated when the first polarization light source and the second polarization light source illuminate the first welding edge and the second welding edge will not interfere with each other. Only the first polarization light source can see the light from the first polarization light source, and only the second polarization light source can see the light from the second polarization light source. In this way, the imaging of the first polarization imaging component and the second polarization imaging component will not interfere with each other.

[0013] Preferably, the first polarization imaging component and the second polarization imaging component are inclined, and their imaging range covers the first welding edge and the second welding edge. The inclined arrangement of the first polarization imaging component and the second polarization imaging component is beneficial to covering the first welding edge and the second welding edge, and is also beneficial to forming light and shadow on the surface defects at the first welding edge and the second welding edge.

[0014] Preferably, both the first polarization imaging component and the second polarization imaging component consist of an imaging device and a polarizing lens disposed in front of the lens of the imaging device. The polarizing lens can adjust the polarization angle to match the polarized light generated by the first polarization light source and the second polarization light source.

[0015] Preferably, the friction welding component limiting platform is a translation platform. The friction welding component under test is fixed on the translation platform and translates relative to the polarization imaging component and the polarization light source. The polarization imaging component and the polarization light source can be designed to be in a fixed state, while the friction welding component limiting platform can drive the friction welding component under test to move horizontally, thereby completing the real-time detection of surface defects.

[0016] Preferably, the friction welding component limiting platform is a rotating platform, and the friction welding component under test is coaxially arranged with the rotating platform. The surface under test on the friction welding component under test rotates around the center of the rotating platform. The friction welding component under test can rotate, which also enables the surface under test to move relative to the polarization imaging component and the polarization light source, thereby completing the real-time detection of surface defects.

[0017] Preferably, the first polarization imaging component, the second polarization imaging component, the first polarization light source, and the second polarization light source are mounted on a movable bracket. The friction welding component limiting platform can be set to a stationary state. The movement of the movable bracket can enable the polarization imaging component and the polarization light source to move relative to the surface of the friction welding component under test, thereby completing the real-time detection of surface defects.

[0018] Secondly, the present invention also relates to a method for real-time surface defect detection of friction stir welding of automotive parts, characterized in that it employs the detection device described in the first aspect, specifically including the following steps:

[0019] S1: Place the friction welded component to be tested on the friction welded component limiting platform and fix it;

[0020] S2: Make the imaging images of the first polarization imaging component and the second polarization imaging component cover the first welding edge and the second welding edge, and adjust the positions of the first polarization light source and the second polarization light source so that the first polarization light source and the second polarization light source simultaneously and obliquely illuminate the first welding edge and the second welding edge from both sides.

[0021] S3: The friction welding component limiting platform performs continuous relative displacement with the polarization imaging component and the polarization light source. The first polarization imaging component and the second polarization imaging component simultaneously image the positions of the first welding edge and the second welding edge. The image is the image after the first polarization light source and the second polarization light source illuminate the first welding edge and the second welding edge.

[0022] If the imaging shows that the first weld edge and / or the second weld edge are shadowed, then the first weld edge and / or the second weld edge have surface defects. The surface defects at the first weld edge and / or the second weld edge can be quickly distinguished by the concentrated processing of the first polarization imaging component and the second polarization imaging component.

[0023] The surface defects mentioned include flash, keyholes, surface depressions, and burrs.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The two light sources used are polarized light sources with polarization directions perpendicular to each other. Corresponding imaging components are equipped with corresponding polarizing lenses, ensuring no interference when both imaging components and the two light sources are activated simultaneously. This allows for real-time detection of moving friction-welded components under test. Thus, this invention combines the advantages of photometric stereoscopic methods, binocular vision methods, and polarized vision technologies, while complementing each other's shortcomings. It effectively solves the problem of existing simple photometric stereoscopic methods being unable to capture images while the object is moving, and it achieves the effects of photometric stereoscopic methods while also addressing the limitation of simple binocular cameras in enhancing defect information. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the polarization optical path of the present invention;

[0028] Figure 3This is a schematic diagram of one embodiment of the friction welding component limiting platform of the present invention.

[0029] Figure label:

[0030] 1. Friction welded component under test; 2. First welding edge; 3. First polarization light source; 4. Second polarization imaging component; 5. First polarization imaging component; 6. Second polarization light source; 7. Second welding edge; 8. Friction welded component limiting platform; 9. Movable bracket. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] Generally, surface defects in friction stir welding (such as flash, keyholes, surface depressions, burrs, and furrows) are defects with a certain height difference. Therefore, photometric stereo method has the advantage of enhancing the image signal of the height difference and facilitates rapid and accurate defect identification by image processing algorithms. However, the photometric stereo method requires at least two consecutive images to be acquired at a single location. For the detection of surface defects in friction stir welding, real-time detection is required, which means that the imaging component and the measured component are in a state of relative movement, making it impossible to acquire more than two images at the same location. Therefore, this invention designs two industrial cameras to meet the requirement of acquiring images simultaneously. The resulting binocular camera possesses the functionality of a 3D camera, effectively enabling the measurement of the corresponding defect size within the field of view.

[0033] However, this creates a problem: multiple images acquired by photometric stereogramming, illuminated by light sources from different directions, create a "shadow" effect, which enhances the height difference defect signal. Configuring two imaging units means that when both are activated simultaneously, the corresponding light sources must also be turned on. Since the light sources corresponding to the imaging cameras are symmetrically arranged, they will illuminate each other's "shadows," causing the "shadows" to disappear and thus negating the basic function of photometric stereogramming.

[0034] Therefore, to effectively address the shortcomings of simple photometric stereo methods in achieving simultaneous photography while moving, and also to overcome the limitation of simple binocular cameras in enhancing defect information, this invention provides the following technical solution: Figure 1-2 As shown, a real-time surface defect detection device for friction stir welding of automotive parts includes a friction stir welding component limiting platform 8 for fixing the friction stir welding component 1 to be tested. The surface of the friction stir welding component 1 to be tested has a first welding edge 2 and a second welding edge 7 side by side. There is no relative movement between the friction stir welding component limiting platform 8 and the friction stir welding component 1 to be tested. The first welding edge 2 and the second welding edge 7 are the two sides of the weld left after friction welding, which are the locations where surface defects occur.

[0035] The polarization imaging component and the polarization light source are set on one side of the friction welding component limiting platform 8 and are relatively displaced in the length direction of the first welding edge 2 and the second welding edge 7. During the detection, the polarization imaging component and the polarization light source can move relative to the friction welding component limiting platform 8 to realize real-time detection of surface defects of friction stir welding.

[0036] The polarization imaging component includes a first polarization imaging component 5 and a second polarization imaging component 4. The first polarization imaging component 5 and the second polarization imaging component 4 are arranged side by side at positions corresponding to the first welding edge 2 and the second welding edge 7, respectively. The imaging of the first polarization imaging component 5 and the second polarization imaging component 4 can cover the first welding edge 2 and the second welding edge 7. The first polarization imaging component 5 and the second polarization imaging component 4 take pictures of the first welding edge 2 and the second welding edge 7 in real time to acquire images, thereby realizing the binocular vision method.

[0037] The polarization light source includes a first polarization light source 3 and a second polarization light source 6. The first polarization light source 3 is located on the side of the second polarization imaging component 4 away from the first polarization imaging component 5, and the second polarization light source 6 is located on the side of the first polarization imaging component 5 away from the second polarization imaging component 4. The first polarization light source 3 and the second polarization light source 6 simultaneously illuminate the first welding edge 2 and the second welding edge 7. The function of the first polarization light source 3 and the second polarization light source 6 is to allow surface defects at the first welding edge 2 and the second welding edge 7 to produce shadows, and at the same time, to make the images of the first polarization imaging component 5 and the second polarization imaging component 4 clearer.

[0038] The first polarization light source 3 and the first polarization imaging component 5 have the same polarization direction, which is the first polarization direction. The second polarization light source 6 and the second polarization imaging component 4 have the same polarization direction, which is the second polarization direction. The first polarization direction and the second polarization direction are perpendicular to each other. By using polarized light, the shadows generated when the first polarization light source 3 and the second polarization light source 6 illuminate the first welding edge 2 and the second welding edge 7 will not interfere with each other. Only the first polarization light source 3 can see the light from the first polarization light source 3, and only the second polarization light source 6 can see the light from the second polarization light source 6. In this way, the imaging of the first polarization imaging component 5 and the second polarization imaging component 4 will not interfere with each other. That is to say, by setting mutually perpendicular polarization angles, the shadows generated by the first polarization light source 3 and the second polarization light source 6 will not be illuminated by each other, so that the photometric stereo method can be applied to the real-time detection of surface defects in friction stir welding.

[0039] Among them, such as Figure 2As shown, light polarization is an existing technology widely used in photographing smooth surfaces such as glassware, water surfaces, display cabinets, painted surfaces, and plastic surfaces. Glare or reflections often occur due to light polarization. Using a polarizing filter during photography, and appropriately rotating the filter, can block polarized light, thereby eliminating or reducing reflections or bright spots on these smooth surfaces. Polarized light is also used in the detection of surface defects in many items, but its purpose is to eliminate reflections and prevent the image from being affected by reflected areas. However, the polarized light in this invention does not eliminate reflections, but rather prevents shadows from being eliminated by the opposite light source, ensuring the existence of shadows and enabling the photometric stereo method to be implemented in the surface defect detection of friction stir welds.

[0040] Preferably, the first polarization imaging component 5 and the second polarization imaging component 4 are inclined, and their imaging range covers the first welding edge 2 and the second welding edge 7. The inclined arrangement of the first polarization imaging component 5 and the second polarization imaging component 4 is beneficial to covering the first welding edge 2 and the second welding edge 7, and is also beneficial to forming light and shadow on the surface defects at the first welding edge 2 and the second welding edge 7.

[0041] Specifically, the first polarization imaging component 5 and the second polarization imaging component 4 are both composed of an imaging device and a polarizing lens disposed in front of the lens of the imaging device. The polarizing lens can adjust the polarization angle to match the polarized light generated by the first polarization light source 3 and the second polarization light source 6. The imaging device can be an industrial camera. The industrial camera will take intermittent or continuous pictures during real-time detection to ensure that each position of the first welding edge 2 and the second welding edge 7 can be captured.

[0042] In this embodiment, the friction welding component limiting platform 8 is a translation platform. The friction welding component 1 under test is fixed on the translation platform and translates relative to the polarization imaging component and the polarization light source. The polarization imaging component and the polarization light source can be designed to be in a fixed state, while the friction welding component limiting platform 8 can drive the friction welding component 1 under test to move horizontally to complete the real-time detection of surface defects. The translation platform can be a conveyor belt, a sliding platform driven by a lead screw, or other structures. In order to facilitate the quick placement and fixing of the friction welding component 1 under test, a positioning structure can also be set on the translation platform. It is not necessary to clamp and position the friction welding component 1 under test; it is only necessary to fix the placement position.

[0043] In this embodiment, as another embodiment of the friction welding component limiting platform 8, the friction welding component limiting platform 8 is a rotating platform. The friction welding component 1 to be tested is coaxially arranged with the rotating platform, and the surface to be tested on the friction welding component 1 rotates around the center of the rotating platform. The friction welding component 1 to be tested can rotate, which also realizes the movement of the surface to be tested relative to the polarization imaging component and the polarization light source, and completes the real-time detection of surface defects. Specifically, the rotating platform can be an indexing turntable, which can precisely control the rotation angle. The surface to be tested of the friction welding component 1 is annular, and the rotation of the friction welding component 1 to be tested meets the requirements of real-time detection.

[0044] In this embodiment, the first polarization imaging component 5, the second polarization imaging component 4, the first polarization light source 3, and the second polarization light source 6 are mounted on a movable bracket 9. The friction welding component limiting platform 8 can be set to a stationary state. The movement of the movable bracket 9 can enable the polarization imaging component and the polarization light source to move relative to the surface of the friction welding component 1 under test, thereby completing the real-time detection of surface defects. The first polarization imaging component 5, the second polarization imaging component 4, the first polarization light source 3, and the second polarization light source 6 can all be rotatably connected to the movable bracket 9, thereby adjusting the angle of the imaging component and the illumination angle of the polarization light source. The movable bracket 9 can be mounted on a robotic arm and can move with the robotic arm. Specific implementation examples:

[0046] Taking the friction stir welding between the motor housing and the water jacket of a new energy vehicle as an example, the motor housing needs to have a circulating cooling water jacket structure inside. The end face of the cooling water jacket is hollow and needs to be sealed with an annular end sleeve. Therefore, the annular end sleeve needs to be welded and fixed to the end face of the motor housing. Thus, the weld seam of the friction stir welding is annular. The structure of the friction stir welding component limiting platform 8 used here is as follows: Figure 3 As shown, the friction welding component limiting platform 8 is equipped with a base for positioning the motor housing. The motor housing can be quickly positioned and placed on the friction welding component limiting platform 8 with the tested surface of the friction stir welding facing upwards. The specific steps include:

[0047] S1: Position the welded motor housing on the friction welding component limiting platform 8;

[0048] S2: Make the imaging images of the first polarization imaging component 5 and the second polarization imaging component 4 cover the first welding edge 2 and the second welding edge 7 on both sides of the weld seam on the upper end face of the motor housing, and adjust the positions of the first polarization light source 3 and the second polarization light source 6 so that the first polarization light source 3 and the second polarization light source 6 simultaneously and obliquely illuminate the first welding edge 2 and the second welding edge 7 from both sides.

[0049] S3: The friction welding component limiting platform 8 and the polarization imaging component and polarization light source undergo continuous relative displacement. This relative displacement can be such that the polarization imaging component and polarization light source on the movable bracket 9 are stationary while the friction welding component limiting platform 8 rotates around the central axis of the motor housing, or the friction welding component limiting platform 8 is stationary while the movable bracket 9 circles around the end face of the motor housing.

[0050] During the relative movement, the first polarization imaging component 5 and the second polarization imaging component 4 simultaneously image the positions of the first welding edge 2 and the second welding edge 7. The imaging here is photographic imaging, and the frequency of taking pictures is related to the speed of relative movement, ensuring that the entire end face of the motor housing can be photographed. The images here are multiple sets of images after the first polarization light source 3 and the second polarization light source 6 illuminate the first welding edge 2 and the second welding edge 7.

[0051] Then, multiple sets of images captured by the first polarization imaging component 5 and the second polarization imaging component 4 are identified. The identification process can be carried out by identification software or manually. The target of identification is the shadow formed at the position of the first welding edge 2 and / or the second welding edge 7. If the imaging shows that the first welding edge 2 and / or the second welding edge 7 forms a shadow, then the first welding edge 2 and / or the second welding edge 7 have surface defects. The surface defects include flash, keyholes, surface depressions and burrs. For example, flash and burrs are raised parts that are obviously higher than the first welding edge 2 and the second welding edge 7. After being irradiated by the first polarization light source 3 and the second polarization light source 6, they will form shadows in the opposite direction of the light source. Keyholes and surface depressions form grooves. After being irradiated by the first polarization light source 3 and the second polarization light source 6, they will also form shadows at the position of the grooves. The only difference is the position of the shadow. The type of surface defect can be identified by the different positions of the shadows.

[0052] After identifying surface defects, the location of the surface defects can be further processed to keep the weld of friction stir welding smooth.

[0053] Therefore, the technical solution of this invention creatively combines the principles of photometric stereo method, binocular vision method and polarization vision, solving the problem of real-time detection of surface defects in friction stir welding, and has good prospects for promotion and market value.

[0054] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0055] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined.

[0056] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0057] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. A method for real-time surface defect detection of automotive parts by friction stir welding, characterized by: The device comprises a friction welding part limiting platform (8) for fixing the measured friction welding part (1), and the measured surface of the measured friction welding part (1) has side-by-side first and second welding edges (2) and (7). A polarization imaging part and a polarization light source are arranged on one side of the friction welding part limiting platform (8) and are relatively displaced in the length direction of the first and second welding edges (2) and (7). The polarization imaging part comprises first and second polarization imaging parts (5) and (4) which are arranged side by side at positions corresponding to the first and second welding edges (2) and (7) respectively. The polarization light source comprises first and second polarization light sources (3) and (6), the first polarization light source (3) is located on the second polarization imaging part (4) away from the first polarization imaging part (5), the second polarization light source (6) is located on the first polarization imaging part (5) away from the second polarization imaging part (4), and the first and second polarization light sources (3) and (6) simultaneously irradiate the first and second welding edges (2) and (7). The light source polarization directions of the first polarization light source (3) and the first polarization imaging part (5) are the same and are the first polarization direction, the light source polarization directions of the second polarization light source (6) and the second polarization imaging part (4) are the same and are the second polarization direction, and the first and second polarization directions are perpendicular. The first and second polarization imaging parts (5) and (4) and the first and second polarization light sources (3) and (6) are installed on a movable support (9). The test method comprises the following steps: S1, placing the measured friction welding part (1) on the friction welding part limiting platform (8) for fixation; S2: covering the imaging pictures of the first and second polarization imaging parts (5) and (4) on the first and second welding edges (2) and (7), adjusting the positions of the first and second polarization light sources (3) and (6), and simultaneously irradiating the first and second welding edges (2) and (7) from both sides at an angle by the first and second polarization light sources (3) and (6) respectively; S3: continuously relatively displacing the friction welding part limiting platform (8) and the polarization imaging part and the polarization light source, and simultaneously imaging the positions of the first and second welding edges (2) and (7) by the first and second polarization imaging parts (5) and (4), which are images after the first and second polarization light sources (3) and (6) irradiate the first and second welding edges (2) and (7); If the imaging shows that the first and / or second welding edges (2) and (7) form a shadow, the first and / or second welding edges (2) and (7) have surface defects.

2. The method of real-time surface defect detection of automotive parts by friction stir welding as claimed in claim 1 wherein: The first polarization imaging component (5) and the second polarization imaging component (4) are arranged obliquely, and the shooting range covers the first welding edge (2) and the second welding edge (7).

3. The method of real-time surface defect detection of automotive parts by friction stir welding as claimed in claim 1 wherein: The first polarization imaging component (5) and the second polarization imaging component (4) are both composed of an imaging device and a polarization lens arranged in front of the lens of the imaging device.

4. The method of real-time surface defect detection of automotive parts by friction stir welding as claimed in claim 1 wherein: The friction welding component limiting platform (8) is a translation platform, and the measured friction welding component (1) is fixed on the translation platform to translate relative to the polarization imaging component and the polarization light source.

5. The method of real-time surface defect detection of automotive parts by friction stir welding as claimed in claim 1 wherein: The friction welding component limiting platform (8) is a rotation platform, and the measured friction welding component (1) is coaxially arranged with the rotation platform, and the measured surface of the measured friction welding component (1) rotates around the center of the rotation platform.

6. The method of real-time surface defect detection of automotive parts by friction stir welding as claimed in claim 1 wherein: The surface defects include burrs, dimples, undercuts and burrs.

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