Device for detecting surface defects of cemented carbide workpieces

Abstract

The present application relates to hard alloy workpiece surface defect detection device, including conveyer belt, cantilever extending to conveyer belt above and camera. Camera is connected with cantilever through parallel four-bar linkage mechanism, and hinged shaft extends along conveyer belt width direction, so that camera can be freely moved up and down and is limited in width direction. Two groups of downward extending fixed rods are fixed symmetrically on camera, and permanent magnet material roller is assembled on the bottom end pivot. The upper surface of conveyer belt is embedded with elastic belt of ferromagnetic material, and the roller and elastic belt keep rolling by magnetic attraction force. The vertical vibration of conveyer belt is transmitted to camera in real time by magnetic attraction of roller and elastic belt, so that camera and workpiece to be measured keep relatively static during imaging process, effectively eliminates defocus and motion blur caused by cantilever shaking and conveyer belt jumping, greatly improves the detection precision of hard alloy workpiece surface micro defect.

Description

Technical Field

[0001] This invention relates to a device for detecting surface defects in cemented carbide workpieces. Background Technology

[0002] As a new type of high-hardness material, cemented carbide workpieces (such as CNC cutting tools) exhibit the following unique characteristics directly related to optical imaging and identification when performing surface defect detection:

[0003] High brittleness makes it extremely sensitive to micro-defects: cemented carbide has low fracture toughness and is prone to micro-cracks or chipping at the micrometer scale during processing. These defects are tiny, but they can easily cause stress concentration and lead to catastrophic brittle fracture of the entire material, thus requiring extremely high detection accuracy.

[0004] High reflectivity leads to flare interference: After fine grinding, its surface exhibits quasi-mirror high reflectivity. During optical inspection, it is very easy to generate local exposure flares in the image due to excessive reflected light, which can obscure the true defects.

[0005] Fine machining textures create noise: The micron-level regular grinding marks remaining on the surface are highly similar to the characteristics of microcracks, making it extremely difficult for algorithms to separate harmful defects from harmless machining textures.

[0006] The aforementioned special characteristics dictate that the surface defect detection of cemented carbide workpieces must employ a high-magnification, narrow-depth-of-field optical imaging system and be carried out under the harsh condition of no relative movement between the camera and the workpiece in order to ensure that minute defects are not missed due to defocusing or blurring.

[0007] However, in actual industrial production sites, due to limitations such as limited equipment space, interference from surrounding machinery, and process layout, inspection cameras often cannot be installed using rigidly supported double-sided gantry frames, but must be installed using a single-sided supported cantilever method.

[0008] The cantilever structure is a typical low-stiffness, single-end constrained structure. When the multi-frequency vibrations of the conveyor frame during operation are transmitted to the cantilever, they are significantly amplified by the long lever arm of the cantilever, causing continuous coupled shaking of the camera at the end. Under high-magnification, narrow-depth-of-field hard alloy detection optical paths, this shaking can be fatal:

[0009] Axial vertical vibration: It is very easy to exceed the narrow depth of field range of the lens (submillimeter level), resulting in dynamic defocusing and blurring of the workpiece image;

[0010] In-plane horizontal jitter: produces motion blur during camera exposure time, causing the gradient features of the micro-crack edges to be lost;

[0011] Angle yaw jitter: causes coaxial or dark field light from a highly reflective surface to deviate from the receiving angle, resulting in flare drift or abnormal shadows, leading to false detections.

[0012] Existing solutions primarily focus on minimizing camera vibration, such as by increasing cantilever stiffness. However, even if the camera achieves perfect vibration damping, it cannot eliminate the inherent vibration of the conveyor belt itself. As long as there is relative displacement between the camera and the workpiece, stable and high-precision detection of micron-level defects in cemented carbide cannot be achieved. Summary of the Invention

[0013] The purpose of this invention is to provide a surface defect detection device for cemented carbide workpieces, specifically designed for cantilever installation scenarios, which solves the above-mentioned technical problems by keeping the camera and the cemented carbide workpiece under test as relatively stationary as possible.

[0014] The technical solution of the present invention is as follows: The cemented carbide workpiece surface defect detection device includes:

[0015] Conveyor belts are used to transport workpieces to be inspected.

[0016] A cantilever that extends above the conveyor belt;

[0017] camera;

[0018] The parallel four-bar linkage includes four links that are hinged in sequence through hinge shafts. The axis of each hinge shaft extends along the width of the conveyor belt. One of the opposing hinge shafts is connected to the cantilever and the other is connected to the camera, so that the camera is in a state where it can move freely in the vertical direction and is limited in the width direction of the conveyor belt.

[0019] A fixing rod is fixed to the camera and extends downwards, with a rotating shaft at its bottom that is vertically arranged parallel to the hinge axis;

[0020] The roller is mounted on a rotating shaft and is made of permanent magnet.

[0021] The elastic belt is embedded on the upper surface of the conveyor belt and located below the rollers. It extends along the length of the conveyor belt and is made of ferromagnetic material.

[0022] There is a magnetic attraction between the roller and the elastic belt below, so that the roller always keeps in contact with the surface of the elastic belt. When the conveyor belt moves the elastic belt, the roller rolls along the elastic belt. When the workpiece to be tested on the conveyor belt vibrates up and down with the conveyor belt, the vibration is transmitted to the camera through the roller and the fixed rod, causing the camera to vibrate up and down synchronously, so that the camera and the workpiece to be tested remain relatively stationary during the imaging process.

[0023] Based on the above scheme, further improvements are made as follows: two sets of fixed rods, rotating shafts, rollers, and elastic belts are provided; two sets of fixed rods are symmetrically fixed on both sides of the camera along the width direction of the conveyor belt, two sets of elastic belts are spaced apart along the width direction of the conveyor belt, and two sets of rollers are symmetrically attached and rolled on the corresponding elastic belts; a detection space is formed between the two sets of rollers for the workpiece to be inspected to pass through, the width of the detection space is the same as the width of the workpiece to be inspected, and the detection space is located directly below the imaging field of view of the camera.

[0024] Based on the above scheme, further improvements are made as follows: guide plates are symmetrically provided on the two sets of fixed rods, each guide plate extends towards the upstream direction of the conveyor belt, and the lateral distance between the two guide plates gradually decreases from upstream to downstream, in order to correct the posture of the workpiece to be inspected, so that the workpiece to be inspected is aligned with the inspection space between the two sets of rollers and the position of the camera lens.

[0025] Based on the above scheme, the following improvements are made: the guide plate has an arc-shaped structure that bends towards the central axis of the camera.

[0026] Based on the above solution, the following improvements are made: the guide plate is made of a non-magnetic material to avoid the guide plate interfering with the magnetic adsorption between the roller and the elastic belt.

[0027] Based on the above solution, the following improvements are made: the upper surface of the elastic belt is flush with the upper surface of the conveyor belt to ensure that when the workpiece to be tested passes under the roller, the bottom surface of the workpiece to be tested and the top surface of the elastic belt are on the same reference plane, thus avoiding collisions between the workpiece to be tested during transportation.

[0028] Based on the above scheme, the following improvements are made: the parallel four-bar linkage is equipped with an elastic element that provides downward preload to the camera. The elastic element is configured to apply an elastic force toward the conveyor belt to the camera, so as to work together with the magnetic attraction force to ensure that the roller does not detach from the elastic belt when rolling.

[0029] Based on the above scheme, the following improvements are made: a counterweight is installed on the camera.

[0030] Based on the above scheme, the following improvements are made: the parallel four-bar linkage also includes a damping damper disposed between the links to suppress secondary high-frequency micro-vibrations when the camera vibrates synchronously up and down with the conveyor belt.

[0031] Based on the above scheme, the following improvements are made: a guide rod is vertically fixed at the upper end of the cantilever and extends downward; a guide hole is opened at the upper part of the fixed rod near the cantilever side, extending along the axis of the fixed rod and open at the top; the guide rod and the guide hole slide together to restrict the vertical sliding of the camera.

[0032] The beneficial effects of this application are:

[0033] This invention breaks away from the traditional design concept of "passively avoiding camera vibration." Through the strong magnetic attraction between the permanent magnet roller and the ferromagnetic elastic belt, the vertical jumps and vibrations of the conveyor belt during operation are transmitted to the camera in real time and with constant amplitude. This ensures that the camera and the workpiece under test vibrate synchronously up and down at the same frequency and phase, achieving "relative stillness" between the two at the moment of image exposure, completely eliminating dynamic defocusing and motion blur caused by vibration.

[0034] The hinge axis of the parallel four-bar linkage extends along the width of the conveyor belt. This structure allows the camera to float vertically while providing extremely high structural rigidity in the horizontal width direction, effectively preventing the camera from swaying or shifting laterally during movement and ensuring that the camera lens center is always aligned with the detection channel.

[0035] Furthermore, the double-set symmetrically arranged fixed rods, rollers, and elastic bands create a precise detection space on both sides of the workpiece. The symmetrically extending arc-shaped guide plates on the fixed rods automatically correct the orientation and center the workpiece conveyed upstream of the conveyor belt, preventing it from deviating from the camera's imaging field of view and ensuring the continuity of online automatic detection. By incorporating downward-facing pre-tensioned elastic elements and damping shock absorbers in the parallel four-bar linkage mechanism, and by adding counterweights to the camera, the rollers are ensured to remain firmly attached to the elastic band during high-speed servoing without jumping or detaching, while also effectively suppressing secondary high-frequency micro-vibrations during high-speed servoing, thus guaranteeing the imaging stability of the ultra-precision optical system under micron-level defect detection. Attached Figure Description

[0036] Figure 1 This is a partial structural schematic diagram of Embodiment 1 of the cemented carbide workpiece surface defect detection device of the present invention; Figure 2 for Figure 1 The right-side view; Figure 3 for Figure 2 A magnified view of a section at point A in the middle; Figure 4 for Figure 2 A magnified view of a section at point B in the middle; Figure 5 for Figure 1 A top-down view; Figure 6 This is a partial structural schematic diagram of the cemented carbide workpiece surface defect detection device in Embodiment 2; In the diagram: 1-conveyor belt, 11-elastic belt, 2-workpiece to be tested, 3-cantilever, 31-guide rod, 4-camera, 5-parallel four-bar linkage, 51-connecting rod, 52-hinge shaft, 6-fixed rod, 61-rotating shaft, 62-guide hole, 7-roller, 8-detection space, 9-guide plate. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that relational terms such as "first" and "second" 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, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0041] Example 1 of the surface defect detection device for cemented carbide workpieces of the present invention: Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown in the figure, this embodiment discloses a surface defect detection device for cemented carbide workpieces, including a conveyor belt 1, a cantilever 3, and a camera 4. The conveyor belt 1 is used to transport the workpiece 2 to be tested in a horizontal direction. The cantilever 3 is fixedly installed on a frame or workshop floor next to the conveyor belt 1 and extends horizontally above the conveyor belt 1.

[0042] like Figure 1 and Figure 2 As shown, a camera 4 is connected to the free end of the cantilever 3 via a parallel four-bar linkage 5. The parallel four-bar linkage 5 includes four links 51 that are hinged sequentially by hinge shafts 52, with the axis of each hinge shaft 52 extending along the width direction of the conveyor belt 1. One of the opposing hinge shafts 52 (i.e., the uppermost hinge shaft) is fixedly connected to the cantilever 3, and the other (i.e., the lowermost hinge shaft) is fixedly connected to the camera 4.

[0043] Since the axial directions of each hinge axis 52 are parallel to the width direction of the conveyor belt 1, the parallel four-bar linkage 5 forms a movable closed chain with parallel double rockers in the vertical plane. This allows the camera 4 to float freely in the vertical direction (up and down direction) under external force, possessing axial adaptive movement capability; at the same time, the parallel four-bar linkage 5 has extremely high lateral constraint rigidity in the direction parallel to the axis of the hinge axis 52 (i.e., the width direction of the conveyor belt 1), which can limit the lateral sway of the camera 4 in the horizontal width direction, thereby ensuring that the camera 4 is in a limited state along the width direction of the conveyor belt 1, and preventing the camera 4 from deviating from the imaging center of the workpiece 2 during swaying.

[0044] like Figure 2 , Figure 4 and Figure 5 As shown, two sets of fixing rods 6 extending vertically downwards are fixed to the camera 4. The two sets of fixing rods 6 are symmetrically fixed to the left and right sides of the camera 4 along the width direction of the conveyor belt 1. Each fixing rod 6 has a vertically mounted pivot 61 at its bottom end, and the axis of the pivot 61 is parallel to the axis of the hinge axis 52 in the parallel four-bar linkage 5 (i.e., extending along the width direction of the conveyor belt 1). Each pivot 61 is rotatably fitted with a roller 7. In this embodiment, the roller 7 is made of a permanent magnet, such as a neodymium iron boron magnet, which has strong internal magnetism.

[0045] Correspondingly, two sets of elastic belts 11 are symmetrically embedded along the length of the upper surface of the conveyor belt 1, with the elastic belts 11 positioned directly below the corresponding rollers 7. The elastic belts 11 are made of ferromagnetic material (e.g., steel belt, flexible iron belt, etc.), and the upper surface of the elastic belts 11 is flush with the upper surface of the conveyor belt 1 (e.g., Figure 4 As shown in the diagram, this ensures that the workpiece 2 under test is smoothly conveyed on the conveyor belt 1, and that when passing under the roller 7, the bottom surface of the workpiece 2 and the top surface of the elastic belt 11 are on the same horizontal reference plane, avoiding collisions or height difference jumps. In other embodiments, the elastic belt 11 embedded in the conveyor belt 1 can be a flexible iron powder rubber belt. Alternatively, it can be a chain structure composed of multiple segments of ferromagnetic metal sheets hinged together along the conveyor belt conveying direction, or a fine steel wire rope mesh structure woven inside the conveyor belt.

[0046] The permanent magnet roller 7 and the ferromagnetic elastic band 11 below it generate a strong magnetic attraction force due to magnetic coupling. This attraction force pulls the fixing rod 6 and the camera 4 downward, so that the roller 7, under the combined action of gravity and magnetic attraction, always maintains a tight physical contact with the surface of the elastic band 11. When the conveyor belt 1 drives the elastic band 11 forward, the roller 7 rolls smoothly along the surface of the elastic band 11 under the action of friction and magnetic attraction.

[0047] When the conveyor belt 1 and the workpiece 2 under test experience dynamic vertical (up-down) vibrations due to environmental vibrations during transport, this vibration affects the elastic belt 11. Because the roller 7 and the elastic belt 11 are tightly magnetically attached, the vertical displacement and vibration of the elastic belt 11 are synchronously and without attenuation transmitted to the roller 7, and then rigidly transmitted to the camera 4 via the rotating shaft 61 and the fixed rod 6. At this time, under the action of the parallel four-bar linkage 5, the camera 4 overcomes its own gravity and the friction of the connecting rod, and thus vibrates synchronously up and down in the vertical direction.

[0048] Because the jumping frequency and amplitude of camera 4 are completely consistent with the workpiece 2 under test on conveyor belt 1 (same frequency and phase), the relative displacement between camera 4 and workpiece 2 in the axial imaging direction is reduced to almost zero. The two are in a relatively static state during the exposure and imaging process of camera 4, which completely solves the problems of dynamic defocusing and motion blur caused by environmental vibration.

[0049] like Figure 2 and Figure 5 As shown, a detection space 8 is formed between the two symmetrically arranged sets of rollers 7, allowing the workpiece 2 to pass through. The width of the detection space 8 is the same as the width of the workpiece 2, so that the workpiece 2 can pass smoothly through the gap between the two sets of rollers 7, and the detection space 8 is directly below the imaging field of view of the camera 4.

[0050] To prevent the workpiece 2 from shifting during transport, guide plates 9 are symmetrically arranged on the upstream side of both sets of fixed rods 6 facing the conveyor belt 1. Each guide plate 9 extends upstream of the conveyor belt 1, and the lateral distance between the two guide plates 9 gradually narrows from upstream to downstream. The guide plates 9 have an arc-shaped structure that curves towards the central axis of the camera 4 (e.g., ...). Figure 5 (As shown). When the workpiece 2 being tested, transported from upstream, exhibits an inclination or positional deviation, the side of the workpiece will slide over the arc-shaped guide plate 9. The guide plate 9 smoothly corrects the posture and centers the workpiece 2, ensuring that it accurately and smoothly enters the detection space 8 between the two rollers 7, thus ensuring that the workpiece 2 is always aligned with the center position of the lens of the camera 4.

[0051] In this embodiment, the guide plate 9 is made of a non-magnetic material, specifically austenitic stainless steel. This material does not produce magnetic shielding or interference, completely avoiding any adverse effects of the guide plate 9 on the magnetic attraction force between the roller 7 and the lower elastic band 11, thus ensuring high rigidity of the magnetic adhesion.

[0052] In this embodiment, the parallel four-bar linkage 5 is further provided with an elastic element (e.g., a tension spring, not shown in the figure) inside (such as between the upper and lower opposing hinge shafts 52 or connecting rods 51) to provide a downward preload to the camera 4. The elastic element is configured to apply an elastic tension to the camera 4 in the direction of the conveyor belt 1. This elastic tension, combined with the weight of the roller 7 itself and the magnetic attraction between the roller 7 and the elastic belt 11, forms a strong downward resultant force, ensuring that the roller 7 can always remain tightly attached to the surface of the elastic belt 11 without transient jumping or detachment when the conveyor belt 1 is running at high speed or experiencing sudden violent jumping.

[0053] Meanwhile, a counterweight (not shown in the figure) is also fixedly installed on camera 4. The counterweight can adjust the center of mass and inertial mass of camera 4 and fixed rod 6 as a whole, so that its gravity, magnetic attraction and linkage restoring force can reach dynamic balance, which is beneficial to improving the response sensitivity of parallel four-bar linkage 5 to low-frequency large amplitude vibration of conveyor belt 1.

[0054] In addition, a damping damper (such as a miniature hydraulic damper, not shown in the figure) is also provided between two adjacent links 51 in the parallel four-bar linkage 5. When the conveyor belt 1 carries the camera 4 and moves up and down synchronously in the vertical direction, the damping damper can absorb high-frequency impact energy, dampen and dissipate the secondary high-frequency micro-vibrations caused by the inertia of the camera 4, thereby ensuring the stability of the camera 4 during motion imaging, so that micron-level surface defects (such as micro-cracks) can be obtained with high contrast and clear images under extremely narrow depth-of-field lenses.

[0055] The present invention also discloses embodiment 2, such as Figure 6 As shown, this is used to further improve the constraint rigidity of the camera in the horizontal and rotational directions under more severe industrial field conditions such as high frequency and large amplitude, ensuring that the camera has only one degree of freedom in the vertical direction.

[0056] Combination Figures 1 to 5 And specifically refer to Figure 6 The specific difference between the second embodiment and the first embodiment is as follows:

[0057] A guide rod 31 extending vertically downwards is fixedly mounted on the lower surface of the cantilever 3. Correspondingly, a guide hole 62 with an upward opening and extending along the axis of the fixed rod 6 is provided on the upper part of the fixed rod 6 near the side of the cantilever 3 (i.e., the fixed rod 6 near the column side of the cantilever 3 in the figure).

[0058] The inner diameter and cross-sectional shape of the guide hole 62 are consistent with the outer diameter and cross-sectional shape of the guide rod 31 (i.e., the two adopt a precision clearance sliding fit). The guide rod 31 is inserted into the guide hole 62 from the upper opening of the guide hole 62, so that the guide hole 62 and the guide rod 31 form a sliding guide fit.

[0059] When the workpiece 2 to be tested on the conveyor belt 1 vibrates vertically along with the conveyor belt 1, the roller 7 and the fixed rod 6 synchronously transmit this vibration to the camera 4, driving the camera 4 and the fixed rod 6 as a whole to move vertically through the parallel four-bar linkage 5. During this movement, the guide hole 62 on the upper part of the fixed rod 6 slides smoothly back and forth in the vertical direction along the guide rod 31 fixed on the cantilever 3.

[0060] Because the precision sliding fit between the guide rod 31 and the guide hole 62 has strict limiting constraints in any radial direction within the horizontal plane, this guiding fit can completely offset and eliminate any slight lateral sway or torsion of the camera 4 caused by mechanical clearance of the hinge shaft 52, slight torsion of the connecting rod 51, or airflow resistance, external lateral mechanical interference forces, etc., that may occur in the parallel four-bar linkage 5 under long-term high-frequency alternating stress. This structure ensures, in terms of physical rigidity, that the camera 4 has only a degree of freedom in the vertical direction, keeping the optical axis of the camera 4 perpendicular throughout the high-speed follow-up process, avoiding any slight geometric distortion, and further guaranteeing the imaging accuracy of detecting fine defects on the surface of cemented carbide workpieces.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A device for detecting surface defects in cemented carbide workpieces, comprising: Conveyor belts are used to transport workpieces to be inspected. A cantilever that extends above the conveyor belt; camera; Its characteristic is that it further includes: The parallel four-bar linkage includes four links that are hinged in sequence through hinge shafts. The axis of each hinge shaft extends along the width of the conveyor belt. One of the opposing hinge shafts is connected to the cantilever and the other is connected to the camera, so that the camera is in a state where it can move freely in the vertical direction and is limited in the width direction of the conveyor belt. A fixing rod is fixed to the camera and extends downwards, with a rotating shaft at its bottom that is vertically arranged parallel to the hinge axis; The roller is mounted on a rotating shaft and is made of permanent magnet. The elastic belt is embedded on the upper surface of the conveyor belt and located below the rollers. It extends along the length of the conveyor belt and is made of ferromagnetic material. There is a magnetic attraction between the roller and the elastic belt below, so that the roller always keeps in contact with the surface of the elastic belt. When the conveyor belt moves the elastic belt, the roller rolls along the elastic belt. When the workpiece to be tested on the conveyor belt vibrates up and down with the conveyor belt, the vibration is transmitted to the camera through the roller and the fixed rod, causing the camera to vibrate up and down synchronously, so that the camera and the workpiece to be tested remain relatively stationary during the imaging process.

2. The cemented carbide workpiece surface defect detection device according to claim 1, characterized in that, Two sets of fixed rods, rotating shafts, rollers, and elastic belts are provided. The two sets of fixed rods are symmetrically fixed on both sides of the camera along the width of the conveyor belt. The two sets of elastic belts are spaced apart along the width of the conveyor belt, and the two sets of rollers are symmetrically attached and roll on the corresponding elastic belts. A detection space is formed between the two sets of rollers for the workpiece to be inspected to pass through. The width of the detection space is the same as the width of the workpiece to be inspected, and the detection space is located directly below the imaging field of view of the camera.

3. The cemented carbide workpiece surface defect detection device according to claim 2, characterized in that, Two sets of fixed rods are symmetrically equipped with guide plates. Each guide plate extends towards the upstream direction of the conveyor belt, and the lateral distance between the two guide plates gradually decreases from upstream to downstream. This is used to correct the posture of the workpiece to be inspected, so that the workpiece to be inspected is aligned with the inspection space between the two sets of rollers and the position of the camera lens.

4. The cemented carbide workpiece surface defect detection device according to claim 3, characterized in that, The guide plate has an arc-shaped structure that bends towards the central axis of the camera.

5. The cemented carbide workpiece surface defect detection device according to claim 4, characterized in that, The guide plate is made of a non-magnetic material to avoid interfering with the magnetic attraction between the roller and the elastic band.

6. The cemented carbide workpiece surface defect detection device according to claim 1, characterized in that, The upper surface of the elastic belt is flush with the upper surface of the conveyor belt to ensure that when the workpiece to be inspected passes under the roller, the bottom surface of the workpiece to be inspected is on the same reference plane as the top surface of the elastic belt, thus avoiding collisions between the workpiece to be inspected during transport.

7. The cemented carbide workpiece surface defect detection device according to claim 1, characterized in that, The parallel four-bar linkage has an internal elastic element that provides downward preload to the camera. The elastic element is configured to apply an elastic force toward the conveyor belt to the camera, which, together with the magnetic attraction force, ensures that the roller does not detach from the elastic belt when rolling.

8. The cemented carbide workpiece surface defect detection device according to claim 1, characterized in that, The camera is equipped with a counterweight.

9. The cemented carbide workpiece surface defect detection device according to claim 1, characterized in that, The parallel four-bar linkage also includes damping dampers disposed between the links to suppress secondary high-frequency micro-vibrations when the camera vibrates synchronously up and down with the conveyor belt.

10. The cemented carbide workpiece surface defect detection device according to claim 1, characterized in that, A guide rod is vertically fixed to the upper end of the cantilever and extends downward. A guide hole with an opening at the top is provided on the upper part of the fixed rod near the cantilever side, which extends along the axis of the fixed rod. The guide rod slides into the guide hole to restrict the vertical sliding of the camera.

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