Synthetic leather surface defect automatic detection device and detection method

Abstract

The invention discloses an automatic detection device for surface defects of synthetic leather, and belongs to the technical field of synthetic leather production lines. The front cleaning mechanism is arranged on the synthetic leather body for cleaning before the detection process, so that defects are exposed; the defect detection and recognition assembly is erected above the conveying mechanism and comprises a linear array camera directly facing the to-be-detected synthetic leather body, a thermal infrared imager arranged side by side with the linear array camera and a laser triangulation 3D sensor located on one side of the linear array camera and the thermal infrared imager and capable of adjusting the angle according to measurement requirements; and the flattening mechanism is arranged above the synthetic leather body, and the flattening mechanism can flatten elastic wrinkles and curls generated due to self elasticity or internal stress release of the synthetic leather body so as to assist identification and detection of the defect detection and identification assembly. Through the design of the front cleaning mechanism, the surface of the synthetic leather is cleaned more thoroughly, and the detection accuracy is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of synthetic leather production lines, and in particular to an automatic detection device and method for surface defects in synthetic leather. Background Technology

[0002] In modern industrial production, synthetic leather (such as artificial leather, PU leather, PVC leather, etc.) is a widely used polymer composite material in footwear, apparel, bags, automotive interiors, and furniture. Its appearance quality directly affects the market value and user experience of the final product. Surface defects that may occur during the production process of synthetic leather (such as scratches, stains, bubbles, color differences, holes, uneven texture, etc.) necessitate the use of automated inspection equipment in modern production lines to identify surface defects online and ensure product consistency, enabling quality inspection of synthetic leather products on high-speed production lines.

[0003] Although some automated testing equipment has been used in synthetic leather production lines, it still has several fundamental technical defects in practical applications. These defects not only stem from the limitations of structural design, but are also closely related to the physical properties of synthetic leather itself. For example, synthetic leather is very easy to adsorb micron-sized dust (such as fiber debris and oil particles) in the environment during winding, cutting or transportation. Existing testing equipment usually omits a dedicated cleaning unit, which causes dust to adhere to the surface of highly reflective or dark synthetic leather, forming visual interference similar to "pseudo-scratches" or "spots". Summary of the Invention

[0004] The purpose of this invention is to provide an automatic detection device and method for surface defects in synthetic leather, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an automatic detection device for surface defects in synthetic leather, comprising: A conveying mechanism used to transport synthetic leather bodies; A pre-cleaning mechanism is installed on the synthetic leather body to clean it before the inspection process, thereby exposing defects. The defect detection and identification component is mounted above the conveying mechanism. The defect detection and identification component includes a line scan camera facing the synthetic leather body to be inspected, an infrared thermal imager arranged side by side with the line scan camera, and a laser triangulation 3D sensor located on one side of the two and whose angle can be adjusted according to the measurement needs. A smoothing mechanism is installed above the synthetic leather body. The smoothing mechanism can smooth out the elastic wrinkles and curls caused by the release of elasticity or internal stress of the synthetic leather body, thereby assisting the defect detection and identification component in identification.

[0006] In a preferred embodiment of this solution, the pre-cleaning mechanism includes: Use a cleaning brush, rotating it to sweep away dust from the surface of the synthetic leather. The suction tube is located behind the cleaning brush; A dust collection box is connected to a suction pipe via a suction hose. The dust collection box contains an air pump connected to the suction pipe and a filter element for filtration.

[0007] In this preferred embodiment, suction holes are provided on the outer wall of the suction pipe at the bottom and top, respectively. The suction hole at the bottom faces the synthetic leather body in the conveying state, and the suction hole at the top faces the position where the defect detection and identification component is installed.

[0008] In a preferred embodiment of this solution, the defect detection and identification component further includes: An integrated mounting plate is provided for mounting line scan cameras, infrared thermal imagers, and laser triangulation 3D sensors. A first micro motor is mounted on the top surface of an integrated mounting plate. The output shaft of the first micro motor extends to one end below the integrated mounting plate and is fixed to an inverted U-shaped adjustment plate. The laser triangulation 3D sensor is hinged in the U-shaped adjustment plate by a pin. A second micro motor is mounted on one outer wall of the U-shaped adjustment plate. The output shaft of the second micro motor is fixedly connected to the pin in the U-shaped adjustment plate, so that the second micro motor drives the laser triangulation 3D sensor to adjust its angle.

[0009] In this preferred embodiment, two supporting columns are symmetrically installed on both outer walls of the conveying mechanism, and a top cover plate is welded to the top of the four supporting columns. A frame plate is welded to the middle of the bottom surface of the top cover plate, and the integrated mounting plate is detachably installed in the cavity of the frame plate.

[0010] In a preferred embodiment, the smoothing mechanism comprises at least four cylinders arranged in a rectangular array on the outer wall of the frame plate, a slider fixed to the free end of the piston rod of each cylinder, an electric telescopic rod movably mounted on the bottom surface of each slider, and a pressing component detachably connected to the bottom telescopic free end of each electric telescopic rod.

[0011] In this preferred embodiment, two mounting ears are symmetrically welded to the bottom surface of each slider component, and a base box is hinged between the two mounting ears via a pin. The end of the electric telescopic rod away from the pressing component is bolted to the bottom surface of the base box. A servo motor is installed on the outer wall of the mounting ear plate, and the output shaft of the servo motor is fixedly connected to the pin in the mounting ear plate, so that the included angle between the pressing component and the surface of the synthetic leather body can be adjusted as needed.

[0012] In a preferred embodiment of this solution, the pressing component includes a smoothing push plate that presses against the surface of the synthetic leather body. A lug is welded to the middle of the top surface of the smoothing push plate. An inverted U-shaped block is hinged to the lug via a pin. An internally threaded sleeve is welded to the top surface of the U-shaped block. A locking bolt knob is transversely passed through the outer wall of the U-shaped block. The outer wall of the lug is provided with multiple internally threaded holes arranged in a ring around the pin, which are threadedly connected to the locking bolt knob. The smoothing mechanism can also press down on the surface of the synthetic leather body while applying a pushing force to stretch it outward, thereby opening up the synthetic leather body. This allows the synthetic leather body to elastically deform and unfold under its own elasticity, exposing defects that were hidden in the natural relaxed state of the synthetic leather body.

[0013] In this preferred embodiment, the smoothing mechanism has multiple modes to push and stretch the synthetic leather body to undergo elastic deformation and expose defects, thereby enabling defect detection in different modes, including but not limited to: four pressing components simultaneously pushing and pulling outwards in opposite directions to open the synthetic leather body; only two opposing pressing components simultaneously pushing and pulling outwards in opposite directions to open the synthetic leather body; two or three adjacent pressing components simultaneously pushing and pulling outwards in opposite directions to open the synthetic leather body; and one pressing component pushing and pulling outwards alone to open the synthetic leather body. The pressing component also includes a pressing ball that can make point contact with the synthetic leather body, and the outer wall of the pressing ball is welded with an internally threaded sleeve.

[0014] An automatic detection method for surface defects in synthetic leather includes the following steps: S1: Place the synthetic leather body to be inspected on the conveyor belt of the conveyor mechanism and convey it at a constant speed from the input end to the output end; S2: The synthetic leather body first passes through the pre-cleaning mechanism, where rotating cleaning brushes remove surface dust, while the vacuum tube sucks up settled dust and suspended particles through the bottom and top suction holes to ensure the surface is clean. S3: The cleaned synthetic leather body enters the defect detection and identification component station, where the linear array camera, infrared thermal imager and laser triangulation 3D sensor are simultaneously activated to collect visible light images, thermal imaging maps and three-dimensional contour data for preliminary detection. S4: If the synthetic leather body has elastic wrinkles or self-rolling, the smoothing mechanism is activated. The cylinder drives the slider to press down and slide the surface smoothing. Then, a preliminary inspection is performed again. If there are no elastic wrinkles or self-rolling, smoothing is not required and a preliminary inspection is performed directly. S5: Further control multiple pressing components of the smoothing mechanism to apply outward pushing and pulling force to the synthetic leather body in a preset mode, so that it produces controllable elastic deformation and unfolds, exposing hidden defects (such as microcracks and subsurface delamination) that are covered by texture or elasticity in the natural state. S6: Trigger the defect detection and recognition component again under the stretched state to perform secondary multimodal imaging and obtain enhanced data containing hidden defects; S7: Perform cross-modal spatiotemporal alignment of the multi-source image data obtained from S3 and S6, and generate a unified defect map through a fusion network. Combine polarization difference, thermal anomaly, and three-dimensional deformation features to comprehensively determine the defect type, location, and severity. S8: Output a test report based on the judgment results, and mark or remove non-conforming products to complete the fully automated testing process.

[0015] Compared with the prior art, the technical effects and advantages of the present invention are as follows: This automatic detection device for surface defects in synthetic leather, through the design of a pre-cleaning mechanism, ensures that the surface of the synthetic leather is thoroughly cleaned before entering the detection process, thereby improving the cleanliness of the synthetic leather surface before detection and improving the accuracy and reliability of subsequent detection. The more thorough surface cleaning achieves high-precision detection and a higher detection accuracy rate compared with existing technologies. The defect detection and identification component consists of a linear scan camera, an infrared thermal imager, and a laser triangulation 3D sensor, used to capture subsurface defects such as color difference, scratches, and bubbles, as well as three-dimensional deformations such as pits and bulges. This multimodal sensor combination not only covers a detection range that traditional single sensors cannot reach, but also improves the robustness and accuracy of the overall detection system through the fusion of data from different types of sensors. For example, the infrared thermal imager detects subsurface defects such as bubbles based on the internal temperature difference of the material, while the laser triangulation 3D sensor can accurately measure three-dimensional deformation, providing rich information dimensions for detection and ensuring that even the smallest or hidden defects can be accurately identified.

[0016] By combining multiple sensor modules, the design enables comprehensive capture of various defect information on the surface and subsurface of synthetic leather, achieving all-round defect detection without blind spots, and providing more comprehensive detection capabilities compared with existing technologies.

[0017] The smoothing mechanism is designed to effectively eliminate wrinkles and curls caused by the release of elasticity or internal stress in synthetic leather, enabling more accurate defect detection and significantly reducing the false detection rate compared to existing technologies. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the smoothing mechanism of the present invention; Figure 3 This is a structural diagram of the frame plate and integrated mounting plate of the present invention in a disassembled state; Figure 4 This is a schematic diagram of the disassembled state of the linear array camera and infrared thermal imager of the present invention. Figure 5 This is a schematic diagram of the installation structure of the laser triangulation 3D sensor of the present invention; Figure 6 This is a schematic diagram of the pre-cleaning mechanism of the present invention; Figure 7 This is a schematic diagram of the installation structure of the electric telescopic pole of the present invention; Figure 8 This is a schematic diagram of the electric telescopic rod and the synthetic leather body of the present invention in a vertical state; Figure 9 This is a schematic diagram of the electric telescopic rod and the synthetic leather body of the present invention in an inclined state; Figure 10 This is a schematic diagram of the structure of the pressure ball of the present invention; Figure 11 This is a schematic diagram of the various modes of pushing and stretching layout of the smoothing mechanism of the present invention on the synthetic leather body.

[0020] Explanation of reference numerals in the attached figures: In the diagram: 1. Conveying mechanism; 2. Pre-cleaning mechanism; 3. Defect detection and identification component; 4. Support column; 5. Top cover plate; 6. Conveyor belt; 7. Synthetic leather body; 8. Conveyor frame; 9. Shelf panel; 10. Dust collection box; 11. Frame plate; 12. Integrated mounting plate; 13. Line scan camera; 14. Infrared thermal imager; 15. First micro motor; 16. Smoothing mechanism; 17. Cylinder; 18. Sliding block; 19. Electric telescopic rod; 20. Smoothing push plate; 21. Positioning guide rod; 22. Limiting plate; 23. Lug block; 24. Silicone protective pad; 25. Mounting limit block; 26. First screw hole; 27. U-shaped block; 28. Locking bolt knob; 29. ​​Laser triangulation 3D sensor; 30. Silicone shock-absorbing washer; 31. First mounting port; 32. Second mounting port; 33. Second screw hole; 34. U-shaped adjusting plate; 35. Second micro motor; 36. Shaft hole; 37. Extension rod; 38. Sealed bearing; 39. Central shaft; 40. Rotary roller; 41. Cleaning brush; 42. Third micro motor; 43. Suction hose; 44. Suction port; 45. Suction connecting hose; 46. Support rib; 47. Mounting ear plate; 48. Base box; 49. Servo motor; 50. Connector; 51. Screw; 52. Internal threaded sleeve; 53. Pressing ball; 54. Silicone protective cover. Detailed Implementation

[0021] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0022] Unless otherwise defined, the directions mentioned herein, such as up, down, left, right, front, back, inside, and outside, are based on the directions shown in the figures of this invention, and are explained here together.

[0023] This embodiment provides, for example Figures 1 to 11 An automatic detection device for surface defects of synthetic leather is shown, characterized in that it includes a conveying mechanism 1 for conveying the synthetic leather body 7, a pre-cleaning mechanism 2 set before the synthetic leather body 7 is cleaned to expose defects, and a defect detection and identification component 3, which is mounted above the conveying mechanism 1. The defect detection and identification component 3 includes a line scan camera 13 facing the synthetic leather body 7 to be detected, an infrared thermal imager 14 arranged side by side with the line scan camera 13, and a laser triangulation 3D sensor 29 located on one side of the two and whose angle can be adjusted according to the measurement needs. The smoothing mechanism 16 is located above the synthetic leather body 7. The smoothing mechanism 16 can smooth out the elastic wrinkles and curls of the synthetic leather body 7 caused by its own elasticity or internal stress release, thereby assisting the defect detection and identification component 3 in identification and detection. Line scan camera 13 is used to capture color differences and scratches on the surface of synthetic leather body 7; Infrared thermal imager 14 detects surface defects such as bubbles based on internal temperature differences of the synthetic leather body 7; The laser triangulation 3D sensor 29 is used to detect the three-dimensional deformation of pits and bulges on the synthetic leather body 7.

[0024] In this embodiment, the pre-cleaning mechanism 2 includes: Cleaning brush 41, rotating in a rotating state, is used to clean the dust on the surface of the synthetic leather body 7; The suction pipe 43 is located behind the cleaning brush 41; The dust collection box 10 is connected to the suction pipe 43 via the suction pipe 45. The dust collection box 10 contains an air pump connected to the suction pipe 45 and a filter element for filtration. The pre-cleaning mechanism 2 adopts a combination design of rotating cleaning brush 41, rear suction pipe 43 and dust collection box 10 with air pump and filter element, which makes the floating dust on the surface of synthetic leather efficiently removed and the dust directionally recycled, realizing closed-loop control of the cleaning process and environmental friendliness. Compared with the existing technology that relies solely on passive dust removal or single brushing method, it significantly reduces the risk of secondary pollution in the detection area and improves the optical imaging quality and long-term reliability of the system.

[0025] In this embodiment, suction holes 44 are respectively provided on the outer wall of the suction pipe 43 at the bottom and top. The suction hole 44 at the bottom faces the synthetic leather body 7 in the conveying state, and the suction hole 44 at the bottom is used to suck up the dust cleaned from the surface of the synthetic leather body 7 to reduce floating dust. The suction hole 44 at the top faces the position where the defect detection and identification component 3 is installed. The suction hole 44 at the top is used to suck up the dust floating on one side of the defect detection and identification component 3, which can not only reduce damage to the defect detection and identification component 3, but also improve the detection and identification accuracy and prevent dust from affecting the visual recognition of the defect detection and identification component 3. The design of opening suction holes 44 at the bottom and top of the suction pipe 43, respectively, facing the synthetic leather body 7 and the defect detection and identification component 3, allows for the simultaneous and zoned suction of settled dust and suspended particles. This achieves dual control over both "settled dust" and "raised dust," effectively preventing dust from adhering to the sensor lens or interfering with the optical path. Compared with the existing technology that only suctions at a single location, this dual-zone suction structure significantly improves cleaning efficiency and the anti-interference capability of the visual detection system, ensuring the consistency and accuracy of multimodal imaging data.

[0026] In this embodiment, the defect detection and identification component 3 further includes: The integrated mounting plate 12 provides support and mounting for the line array camera 13, the infrared thermal imager 14, and the laser triangulation 3D sensor 29; The first micro motor 15 is mounted on the top surface of the integrated mounting plate 12. The output shaft of the first micro motor 15 extends longitudinally through the integrated mounting plate 12 and is connected to the integrated mounting plate 12 via a bearing. The top surface of the integrated mounting plate 12 has a first mounting port 31 for mounting the line array camera 13 and a second mounting port 32 for mounting the infrared thermal imager 14. The output shaft of the first micro motor 15 extends to one end below the integrated mounting plate 12 and is fixed to an inverted U-shaped adjustment plate 34. The laser triangulation 3D sensor 29 is hinged in the U-shaped adjustment plate 34 by a pin. A second micro motor 35 is installed on one outer wall of the U-shaped adjustment plate 34. The output shaft of the second micro motor 35 is fixedly connected to the pin in the U-shaped adjustment plate 34, so that the second micro motor 35 drives the laser triangulation 3D sensor 29 to adjust the angle. The first micro motor 15 can drive the U-shaped adjustment plate 34 to rotate circumferentially below the integrated mounting plate 12, so that not only the circumferential position of the laser triangulation 3D sensor 29 can be adjusted, but also the axial position can be adjusted to meet the needs of different angle detection. A shaft hole 36 for mounting the output shaft of the first micro motor 15 is opened on the top surface of the U-shaped adjustment plate 34. A keyway is opened on the inner wall of the shaft hole 36, and a key block adapted to the keyway is welded to the outer wall of the output shaft of the first micro motor 15. The defect detection and identification component 3 uses an integrated mounting plate 12 to carry a linear array camera 13 and an infrared thermal imager 14. It uses a first micro motor 15 to drive a U-shaped adjustment plate 34 to drive a laser triangulation 3D sensor 29 to achieve circumferential and axial angle linkage adjustment. This allows the 3D sensor to dynamically adjust the incident angle and observation angle according to different materials, textures or defect types, achieving optimal capture of complex three-dimensional deformation features. Compared with existing 3D detection structures with fixed angles or only single-degree-of-freedom adjustment, this dual-motor collaborative adjustment mechanism significantly enhances the sensitivity and adaptability to small deformations such as pits and bulges, and is especially suitable for highly reflective or densely textured synthetic leather surfaces.

[0027] In this embodiment, two support columns 4 are symmetrically installed on both outer walls of the conveying mechanism 1. A top cover plate 5 is welded to the top of the four support columns 4. A frame plate 11 is welded to the middle of the bottom surface of the top cover plate 5. The integrated mounting plate 12 is detachably installed in the cavity of the frame plate 11. Multiple mounting limiting blocks 25 are welded in a rectangular array on the inner wall of the frame plate 11. Each mounting limiting block 25 has a first screw hole 26 longitudinally opened in it. Multiple second screw holes 33 are opened in a rectangular array at the top edge of the integrated mounting plate 12. When the integrated mounting plate 12 needs to be installed, it is lifted up from the... The lower opening of the frame plate 11 is placed in the cavity of the frame plate 11. Bolts are screwed into each of the second screw holes 33 so that the screw end of the bolt is adapted to the thread of the first screw hole 26, so that the integrated mounting plate 12 is installed together with multiple mounting limit blocks 25. When the integrated mounting plate 12 needs to be disassembled, only the bolts need to be removed. A silicone shock-absorbing washer 30 is bonded to the outer periphery of the integrated mounting plate 12. The outer wall of the silicone shock-absorbing washer 30 elastically abuts against the inner wall of the frame plate 11, so that the silicone shock-absorbing washer 30 is between the frame plate 11 and the integrated mounting plate 12, and is used to buffer and absorb shock of the integrated mounting plate 12. The integrated mounting plate 12 is detachably installed inside the frame plate 11 cavity, and is designed with silicone damping washers 30 for buffering and limiting. This design ensures that the entire sensing module maintains high rigidity while having good vibration resistance, achieving image acquisition stability during long-term high-speed operation. Compared with the rigid direct connection or installation method without damping measures in the prior art, this structure effectively suppresses the interference of transmission vibration on high-precision optical devices, avoids image blurring or data drift, and facilitates maintenance and replacement, thus improving the serviceability of the equipment.

[0028] In this embodiment, the smoothing mechanism 16 includes at least four cylinders 17 arranged in a rectangular array on the outer wall of the frame plate 11, a slider 18 fixed to the free end of the piston rod of each cylinder 17, an electric telescopic rod 19 movably mounted on the bottom surface of each slider 18, and a pressing component detachably connected to the bottom telescopic free end of each electric telescopic rod 19. The electric telescopic rod 19 drives the pressing component to descend, so that the pressing component contacts the surface of the synthetic leather body 7. The piston rod of the cylinder 17 extends, driving the slider 18 to move forward in a straight line, so that the electric telescopic rod 19 moves synchronously with the slider 18, thereby causing the pressing component to slide and rub against the surface of the synthetic leather body 7. Thus, the pressing component smooths the synthetic leather body 7 by extending the cylinder 17 while pressing down on the synthetic leather body 7. A connector 50 is fixed to the bottom end of the electric telescopic rod 19. A screw 51 is welded to the bottom surface of the connector 50. The screw 51 is threadedly connected to an internal threaded sleeve 52. The bottom of the internal threaded sleeve 52 is connected to the pressing component. The smoothing mechanism 16 adopts a design where the cylinder 17 drives the slider 18 to push down and slide the electric telescopic rod 19 laterally. This allows the pressing component to not only apply vertical pressure but also slide and rub along the surface of the synthetic leather to smooth out elastic wrinkles, achieving a combination of dynamic smoothing and static flattening. Compared with existing smoothing methods that only use static pressure rollers or fixed pressure plates, this active sliding smoothing mechanism can more effectively eliminate local curling caused by the release of internal stress in the material, ensuring that the area to be inspected is flat and fits the conveying surface, providing ideal conditions for subsequent high-resolution imaging.

[0029] In this embodiment, two mounting ears 47 are symmetrically welded to the bottom surface of each slider 18, so that a base box 48 is hinged between the two mounting ears 47 by a pin. The end of the electric telescopic rod 19 away from the pressing component is bolted to the bottom surface of the base box 48. A servo motor 49 is installed on the outer wall of the mounting ears 47, and the output shaft of the servo motor 49 is fixedly connected to the pin in the mounting ears 47, so that the included angle between the pressing component and the surface of the synthetic leather body 7 can be adjusted as needed (as shown in the attached figure). Figure 9(As shown). Each slider 18 is connected to the top cover plate 5 via a positioning guide assembly; so that when tilting force is required on the surface of the synthetic leather body 7, the servo motor 49 drives the base box 48 to adjust the angle, thereby adjusting the electric telescopic rod 19 to the required tilt angle; the positioning guide assembly includes positioning guide rods 21 symmetrically arranged on both sides of each cylinder 17 and a limiting connecting plate 22 welded to one end of each positioning guide rod 21 away from the frame plate 11. The other end of each positioning guide rod 21 is welded to the outer wall of the frame plate 11, and each limiting connecting plate 22 is welded to the bottom surface of the top cover plate 5. Each positioning guide rod 21 passes through the adjacent slider 18, so that when the piston rod of the cylinder 17 drives the slider 18 to move telescopically, the slider 18 is positioned and slid on the two adjacent positioning guide rods 21, thereby not only guiding and positioning the slider 18, but also supporting and bearing the slider 18, reducing the shaking of the slider 18. A hinged base box 48 is provided on the bottom surface of the slider 18, and the tilt angle of the electric telescopic rod 19 is adjusted by a servo motor 49. At the same time, it is combined with the positioning guide rod 21 and the limiting connecting plate 22 to form a rigid guiding system. This design allows the posture of the pressing component to be accurately controlled in real time and the movement trajectory to be highly stable. It realizes adaptive bonding force for synthetic leather of different thicknesses and elastic moduli. Compared with the smoothing structure in the prior art where the angle is not adjustable or the guide is loose, this design avoids scratches or ineffective smoothing caused by angle deviation and prevents positioning errors caused by slider wobbling. It significantly improves the repeatability accuracy and safety of the smoothing action.

[0030] In this embodiment, the pressing component includes a smoothing push plate 20 that presses against the surface of the synthetic leather body 7. A lug 23 is welded to the center of the top surface of the smoothing push plate 20. An inverted U-shaped block 27 is hinged to the lug 23 via a pin. An internally threaded sleeve 52 is welded to the top surface of the U-shaped block 27. A locking bolt knob 28 is transversely passed through the outer wall of the U-shaped block 27. The outer wall of the lug 23 has multiple internally threaded holes arranged in a circular array around the pin, which are threaded to the locking bolt knob 28. When it is necessary to tilt and push the synthetic leather body 7, the lug 23 is first adjusted to the required angle in the U-shaped block 27, which allows the smoothing push plate to be tilted. The smoothing push plate 20 is parallel to the surface of the synthetic leather body 7 so that it can press down on the surface of the synthetic leather body 7. Then, tighten the locking bolt knob 28 so that the locking bolt knob 28 locks the angle of the lug block 23 in the U-shaped block 27. At the same time, the servo motor 49 adjusts the tilt angle of the electric telescopic rod 19, so that the smoothing push plate 20 is parallel to the synthetic leather body 7. This allows for different tilt angles to push and open the synthetic leather body 7. Each smoothing push plate 20 has a silicone protective pad 24 glued to its bottom surface. The silicone protective pad 24 and the silicone protective cover 54 are for anti-slip and protection of the synthetic leather to prevent scratches. The smoothing mechanism 16 can also press down on the surface of the synthetic leather body 7 while simultaneously applying outward thrust and stretching, thereby expanding the synthetic leather body 7. This allows the synthetic leather body 7 to elastically deform and unfold under its own elasticity, exposing defects that are hidden in the natural relaxed state of the synthetic leather body 7. If the synthetic leather body 7 is not elastically deformed or unfolded, it is easy for minor defects to be hidden in the natural relaxed state (without external force) or in its own elastic contraction state. These defects can only be exposed and detected by expanding the synthetic leather body 7, such as microcracks hidden in the texture depressions. The smoothing pusher 20 can be precisely parallel to the surface of synthetic leather under the dual adjustment of mechanical pre-adjustment and servo electronic control, achieving flexible, non-destructive and highly conforming contact smoothing; at the same time, by pushing and pulling outward to stretch the synthetic leather to produce controllable elastic deformation, hidden defects such as micro-cracks and delamination that are naturally concealed by the texture are exposed; compared with the existing technology that only flattens the surface and cannot stimulate hidden defects, this integrated "stretching-flattening-detection" mechanism greatly expands the defect detection range, and is especially suitable for synthetic leather products with high elasticity and high texture density.

[0031] In this embodiment, the smoothing mechanism 16 has multiple modes to push the stretched synthetic leather body 7 to undergo elastic deformation and expose defects, enabling defect detection in different modes, including but not limited to: four pressing components (as shown in the attached document). Figure 11 The four pressing components (A, B, C, and D) simultaneously push and pull outwards in opposite directions to open the synthetic leather body. Only two opposing pressing components (as shown in the attached diagram) Figure 11 The two pressing components A and C, or B and D, have the following characteristics: When A and C are in contact, B and D do not contact the synthetic leather body 7 or press down vertically on the synthetic leather body 7, thus assisting in the stretching of A and C; when B and D stretch the synthetic leather body 7, A and C do not contact the synthetic leather body 7 or press down vertically on the synthetic leather body 7, thus assisting in the stretching of B and D. Simultaneously, they push and pull outwards in opposite directions to open up the synthetic leather body 7 and the two or three adjacent pressing components (as shown in the attached diagram). Figure 11 Two pressing parts, A and B, or three pressing parts, A, B and C, are used, while the last two or the last pressing part does not contact the synthetic leather body 7 or presses down vertically on the synthetic leather body 7 to assist in stretching. At the same time, the synthetic leather body 7 is pushed and pulled outwards in opposite directions, and one of the pressing parts (such as A) presses down on the synthetic leather body 7. The other pressing part (such as C) pushes and pulls outwards on the synthetic leather body 7 separately. The other two (such as B and D) do not contact the synthetic leather body 7 or press down vertically on the synthetic leather body 7 to assist in stretching C. The pressing component also includes a pressing ball 53 that can make contact with the synthetic leather body at 7 points. The outer wall of the pressing ball 53 is welded with an internally threaded sleeve 52. The outer ring of the pressing ball 53 is fitted with a silicone protective sleeve 54. When the pressing ball 53 makes contact with the synthetic leather body at 7 points, it can reduce the area covered, thereby increasing the detection range. The pressing component can be selected as needed, and is connected by the threaded connection of the screw 51 and the internal threaded sleeve 52, facilitating installation and disassembly and thus aiding in the replacement of the pressing component. The smoothing mechanism 16 supports multiple stretching modes (such as four-way synchronous, opposing stretching, adjacent combination, single-sided push-pull, etc.) and can be equipped with a point-contact pressing ball 53, enabling the system to flexibly switch detection strategies according to defect type, material characteristics, or process requirements, achieving multi-scale defect excitation capabilities from macroscopic flatness to local micro-deformation; due to the small point contact occlusion area of ​​the pressing ball 53, the coverage of the visual inspection area below can be reduced, improving the utilization rate of the inspection field of view; compared with the existing single-mode, fixed contact smoothing device, this multi-functional, modular design significantly enhances the versatility and inspection depth of the equipment, meeting the diverse quality control needs of high-end synthetic leather production lines.

[0032] In this embodiment, extension rods 37 are welded to the outer walls of the two support columns 4 near the input end of the conveying mechanism 1. A central shaft 39 is rotatably mounted between the two extension rods 37 via a sealed bearing 38. A rotating roller 40 is fixed around the central shaft 39, and a cleaning brush 41 is fixed to the outer wall of the rotating roller 40. A third micro motor 42 for driving the central shaft 39 is fixedly mounted on the outer wall of one of the extension rods 37. The output shaft of the third micro motor 42 is fixedly connected to one end of the central shaft 39, so that the third micro motor 42 can drive the central shaft 39 to rotate, thereby driving the rotating roller 40 and the cleaning brush 41 to rotate synchronously, so that the cleaning brush 41 cleans dust. Welded on the support legs of the conveying mechanism 1 A shelf plate 9 is provided to support the dust collection box 10, and the dust collection box 10 is installed on the shelf plate 9; a support rib 46 is also welded between the bottom surface of each extension rod 37 and the outer wall of the adjacent support column 4; the conveying mechanism 1 includes a conveyor frame 8, a conveyor belt 6 set on the conveyor frame 8 and a support bracket installed at the bottom of the conveyor frame 8. The synthetic leather body 7 is conveyed from the input end on the conveyor belt 6. First, it is pre-cleaned by the pre-cleaning mechanism 2, and then the synthetic leather body 7 is preliminarily inspected by the defect detection and identification component 3. If it needs to be smoothed, it is smoothed first and then preliminarily inspected. Then, it is elastically stretched and opened by the smoothing mechanism 16 for secondary inspection, and finally it is output from the output end of the conveyor belt 6.

[0033] An automatic detection method for surface defects in synthetic leather includes the following steps: S1: The synthetic leather body 7 to be inspected is placed on the conveyor belt 6 of the conveyor mechanism 1 and conveyed at a constant speed from the input end to the output end; the PLC controls the speed and start / stop of the conveyor belt 6 through the servo motor to ensure that the synthetic leather body 7 is transmitted at a constant speed so that subsequent workstations can accurately collect data.

[0034] S2: The synthetic leather body 7 first passes through the pre-cleaning mechanism 2, where the rotating cleaning brush 41 sweeps away the surface dust. At the same time, the suction pipe 43 sucks up the settled dust and suspended particles through the suction holes 44 at the bottom and top, respectively, to ensure the surface is clean. The PLC controls the third micro motor 42 to drive the central shaft 39 to rotate, so that the cleaning brush 41 rotates to clean the surface of the synthetic leather body 7. At the same time, the air pump in the dust collection box 10 is activated to suck up the dust through the suction pipe 45 and the suction pipe 43.

[0035] S3: After cleaning, the synthetic leather body 7 enters the defect detection and identification component 3 station, and the line scan camera 13, infrared thermal imager 14 and laser triangulation 3D sensor 29 are started simultaneously to collect visible light images, thermal imaging spectra and three-dimensional contour data for preliminary detection; the PLC controls the first micro motor 15 and the second micro motor 35 to adjust the position and angle of the line scan camera 13, infrared thermal imager 14 and laser triangulation 3D sensor 29 on the integrated mounting plate 12 to ensure the best imaging effect; these sensors are started to collect multimodal data and obtain preliminary detection results.

[0036] S4: If the synthetic leather body 7 has elastic wrinkles or self-rolling, the smoothing mechanism 16 is activated. The cylinder 17 drives the slider 18 to press down and smooth the surface, then a preliminary inspection is performed again. If there are no elastic wrinkles or self-rolling, smoothing is not required, and the preliminary inspection proceeds directly. The PLC determines whether the synthetic leather body 7 has elastic wrinkles or self-rolling based on data from the line scan camera 13 or the laser triangulation 3D sensor 29. If elastic wrinkles or self-rolling are present, the PLC controls the cylinder 17 to extend, driving the slider 18 to move, which in turn drives the electric telescopic rod 19 and the pressing component to press down and smooth the surface of the synthetic leather body 7. Then, the line scan camera 13, infrared thermal imager 14, and laser triangulation 3D sensor 29 are triggered again for preliminary inspection. If there are no elastic wrinkles or self-rolling, the PLC skips the smoothing step and continues with the preliminary inspection.

[0037] S5: Further control the multiple pressing components of the smoothing mechanism 16 to apply outward pushing and pulling force to the synthetic leather body 7 in a preset mode, so that it produces controllable elastic deformation and unfolds, so that hidden defects such as micro-cracks and subsurface delamination that are covered by texture or elasticity in the natural state are exposed; the PLC controls the cylinder 17 and servo motor 49 to work together according to the preset mode (such as four pressing components pushing and pulling outward in opposite directions at the same time, stretching relative to two pressing components, etc.), and adjusts the angle and position of the electric telescopic rod 19 so that the pressing components apply outward pushing and pulling force to the synthetic leather body 7 in different modes to achieve elastic deformation.

[0038] S6: The defect detection and identification component 3 is triggered again under the stretched state to perform secondary multimodal imaging and obtain enhanced data containing hidden defects; the PLC controls the linear array camera 13, the infrared thermal imager 14 and the laser triangulation 3D sensor 29 to re-acquire multi-source image data under the elastic deformation state of the synthetic leather body 7 and obtain enhanced data.

[0039] S7: Perform cross-modal spatiotemporal alignment on the multi-source image data obtained from S3 and S6, and generate a unified defect map through a fusion network. Combine polarization difference, thermal anomaly, and three-dimensional deformation features to comprehensively determine the defect type, location, and severity. The PLC transmits the multi-source image data obtained from the preliminary detection in S3 and the secondary detection in S6 to the computer vision algorithm module. This module uses cross-modal alignment and fusion network to process the data, generate a unified defect map, and feeds the results back to the PLC.

[0040] S8: Output an inspection report based on the judgment results, and mark or remove non-conforming products to complete the fully automated inspection process. The PLC controls an inkjet printer or other marking equipment to mark non-conforming products based on the defect judgment results returned by the computer vision algorithm module, or removes them from the production line via a robotic arm, thus completing the inspection process.

[0041] It should be noted that, in this document, relational terms such as "one" and "two" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automatic detection device for surface defects in synthetic leather, characterized in that, include: Conveying mechanism (1), which is used to convey synthetic leather body (7); A pre-cleaning mechanism (2) is installed on the synthetic leather body (7) to clean it before the inspection process, thereby exposing defects; The defect detection and identification component (3) is mounted above the conveying mechanism (1). The defect detection and identification component (3) includes a line array camera (13) facing the synthetic leather body (7) to be inspected, an infrared thermal imager (14), and a laser triangulation 3D sensor (29) that can adjust the angle according to the measurement needs. The smoothing mechanism (16) is located above the synthetic leather body (7). The smoothing mechanism (16) can smooth out the elastic wrinkles and curls of the synthetic leather body (7) caused by its own elasticity or internal stress release, thereby assisting the defect detection and identification component (3) in identification and detection.

2. The automatic detection device for surface defects of synthetic leather according to claim 1, characterized in that: The pre-cleaning mechanism (2) includes: Cleaning brush (41) is used to clean dust from the surface of the synthetic leather body (7) by rotating it. The suction pipe (43) is located behind the cleaning brush (41); The dust collection box (10) is connected to the suction pipe (43) via the suction pipe (45). The dust collection box (10) has an air pump connected to the suction pipe (45) and a filter element for filtration.

3. The automatic detection device for surface defects of synthetic leather according to claim 2, characterized in that: A suction hole (44) is provided on the outer wall of the suction pipe (43) at the bottom and the top respectively. The suction hole (44) at the bottom faces the synthetic leather body (7) in the conveying state, and the suction hole (44) at the top faces the position where the defect detection and identification component (3) is installed.

4. The automatic detection device for surface defects of synthetic leather according to claim 3, characterized in that: The defect detection and identification component (3) also includes: An integrated mounting plate (12) is provided for mounting the line array camera (13), the infrared thermal imager (14), and the laser triangulation 3D sensor (29); A first micro motor (15) is mounted on the top surface of an integrated mounting plate (12). The output shaft of the first micro motor (15) extends to one end below the integrated mounting plate (12) and is fixed to an inverted U-shaped adjustment plate (34). The laser triangulation 3D sensor (29) is hinged in the U-shaped adjustment plate (34) by a pin. A second micro motor (35) is mounted on one outer wall of the U-shaped adjustment plate (34). The output shaft of the second micro motor (35) is fixedly connected to the pin in the U-shaped adjustment plate (34), so that the second micro motor (35) drives the laser triangulation 3D sensor (29) to adjust the angle.

5. The automatic detection device for surface defects of synthetic leather according to claim 4, characterized in that: The conveying mechanism (1) has two supporting columns (4) symmetrically installed on both sides of its outer wall. The top of the four supporting columns (4) is welded with a top cover plate (5). A frame plate (11) is welded to the middle of the bottom surface of the top cover plate (5). The integrated mounting plate (12) is detachably installed in the cavity of the frame plate (11).

6. The automatic detection device for surface defects of synthetic leather according to claim 5, characterized in that: The smoothing mechanism (16) includes at least four cylinders (17) mounted in a rectangular array on the outer wall of the periphery of the frame plate (11), sliders (18) fixed to the free end of the piston rod of each cylinder (17), electric telescopic rods (19) movably mounted on the bottom surface of each slider (18), and a pressing component detachably connected to the bottom telescopic free end of each electric telescopic rod (19).

7. The automatic detection device for surface defects of synthetic leather according to claim 6, characterized in that: Each slider (18) has two mounting ear plates (47) symmetrically welded to its bottom surface, such that a base box (48) is hinged between the two mounting ear plates (47) by a pin. The end of the electric telescopic rod (19) away from the pressing component is bolted to the bottom surface of the base box (48). A servo motor (49) is installed on the outer wall of the mounting ear plate (47), and the output shaft of the servo motor (49) is fixedly connected to the pin in the mounting ear plate (47), so that the included angle between the pressing component and the surface of the synthetic leather body (7) can be adjusted as needed.

8. The automatic detection device for surface defects of synthetic leather according to claim 7, characterized in that: The pressing component includes a smoothing push plate (20) that presses against the surface of the synthetic leather body (7) in surface contact. A lug (23) is welded to the middle of the top surface of the smoothing push plate (20). An inverted U-shaped block (27) is hinged to the lug (23) by a pin. An internal thread sleeve (52) is welded to the top surface of the U-shaped block (27). A locking bolt knob (28) is transversely penetrating the outer wall of the U-shaped block (27). The outer wall of the lug (23) is provided with multiple internal thread holes that are threadedly connected to the locking bolt knob (28) in a circular array with the pin as the center. The smoothing mechanism (16) can also press down on the surface of the synthetic leather body (7) and simultaneously apply a pushing force to stretch it outward, thereby opening up the synthetic leather body (7) so that the synthetic leather body (7) can elastically deform and spread out under its own elasticity, thus exposing the defects that were hidden in the natural relaxed state of the synthetic leather body (7).

9. An automatic detection device for surface defects of synthetic leather according to claim 8, characterized in that: The smoothing mechanism (16) has multiple modes to push and stretch the synthetic leather body (7) to undergo elastic deformation and expose defects, thereby enabling defect detection in different modes, including but not limited to: four pressing components simultaneously pushing and pulling outwards in opposite directions to open the synthetic leather body (7), only two opposing pressing components simultaneously pushing and pulling outwards in opposite directions to open the synthetic leather body (7), two or three adjacent pressing components simultaneously pushing and pulling outwards in opposite directions to open the synthetic leather body (7), and one pressing component pushing and pulling outwards in isolation to open the synthetic leather body (7). The pressing component also includes a pressing ball (53) that can make point contact with the synthetic leather body (7), and the outer wall of the pressing ball (53) is welded with an internally threaded sleeve (52).

10. An automatic detection method for surface defects in synthetic leather, characterized in that, Includes the following steps: S1: Place the synthetic leather body (7) to be inspected on the conveyor belt (6) of the conveyor mechanism (1) and convey it at a constant speed from the input end to the output end; S2: The synthetic leather body (7) first passes through the pre-cleaning mechanism (2), where the rotating cleaning brush (41) removes surface dust, while the suction pipe (43) sucks up settled dust and suspended particles through the suction holes (44) at the bottom and top respectively, ensuring the surface is clean; S3: The cleaned synthetic leather body (7) enters the defect detection and identification component (3) station, and the linear array camera (13), infrared thermal imager (14) and laser triangulation 3D sensor (29) are started simultaneously to collect visible light images, thermal imaging spectra and three-dimensional contour data for preliminary detection. S4: If the synthetic leather body (7) has elastic wrinkles or self-rolling, the smoothing mechanism (16) is activated. The cylinder (17) drives the slider (18) to press down and slide the surface smoothing. Then, a preliminary inspection is performed again. If there are no elastic wrinkles or self-rolling, smoothing is not required and a preliminary inspection is performed directly. S5: Further control the multiple pressing parts of the smoothing mechanism (16) to apply outward pushing and pulling force to the synthetic leather body (7) in a preset mode, so that it produces controllable elastic deformation and unfolds, so that the hidden defects that are covered by texture or elasticity in the natural state are exposed. S6: Trigger the defect detection and identification component (3) again under the stretched state to perform secondary multimodal imaging and obtain enhanced data containing hidden defects; S7: Perform cross-modal spatiotemporal alignment of the multi-source image data obtained from S3 and S6, and generate a unified defect map through a fusion network. Combine polarization difference, thermal anomaly, and three-dimensional deformation features to comprehensively determine the defect type, location, and severity. S8: Output a test report based on the judgment results, and mark or remove non-conforming products to complete the fully automated testing process.

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