A core wire weld appearance inspection device

Abstract

The application discloses a kind of core wire weld point appearance detection equipment, including the fixed inclination a>0 of relative horizontal plane with platform, imaging and lighting system being set on it, and processing unit being connected therewith.Imaging unit is formed by first, second industrial camera, respectively installed on angle adjustable mechanism with scale and locking, so that the optical axis of two cameras forms adjustable included angle b, c relative to platform plane, and satisfy c>b;Lighting unit is coaxial / combination light source arranged cooperatively with camera, for uniformly illuminating core wire weld point area.Processing unit obtains double-view images collected under setting b, c and outputs weld point appearance detection result.The scheme suppresses highlight and occlusion by inclination bearing and complementary view angle imaging, highlights weld point details, and improves detection stability and accuracy.

Description

Technical Field

[0001] This invention relates to the field of machine vision and automated inspection equipment technology, and in particular to a device for inspecting the appearance of core wire solder joints, specifically a solder joint imaging and inspection device consisting of an imaging mechanism with an adjustable camera angle and a stage with a certain tilt angle. Background Technology

[0002] In electronics manufacturing, the visual inspection of wire solder joints is a crucial step in ensuring product consistency and reliability. Currently, the industry still relies heavily on manual visual inspection, which is inefficient and inconsistent. Traditional machine vision / algorithms that have been applied are insufficient in feature extraction and generalization capabilities when solder joints are small, diverse in shape, and have complex defect types, resulting in unstable inspection results.

[0003] In addition, typical products often have two solder joints on different surfaces. In actual production lines, imaging from different angles is required to cover key features. If the camera is installed at a fixed angle or the stage is placed horizontally, there are often specular reflections, shadows, and blind spots in the field of view, which leads to unclear defect boundaries and increased risk of false positives and false negatives.

[0004] Many existing solutions use embedded "smart cameras" for integrated installation. Although the layout is compact, the input / output ports and expansion capabilities are limited, making it difficult to flexibly configure multi-angle shooting and linkage control, and also inconvenient to perform detailed debugging and expansion on site.

[0005] Therefore, while maintaining production line cycle time and ease of assembly, how can we provide an imaging structure with an adjustable camera mounting angle and an imaging structure that improves the light reception and visibility of solder joints through a platform with a certain tilt angle, so as to adapt to the imaging requirements of different products and different solder joint surfaces and reduce the recognition difficulties caused by reflection and obstruction? Summary of the Invention

[0006] To address the issues of glare, obstruction, and blind spots at the core wire solder joints when placed horizontally and viewed from a fixed angle, an appearance inspection device with an adjustable camera angle and a tilting platform is proposed.

[0007] Specifically, this invention provides a device for inspecting the appearance of wire solder joints, comprising:

[0008] A platform for supporting the product to be tested, wherein the platform is fixed at an angle α (α > 0) relative to the horizontal plane;

[0009] The imaging unit includes a first industrial camera and a second industrial camera, which are respectively mounted on an angle-adjustable mounting mechanism. The mounting mechanism is configured such that the optical axis of the first industrial camera forms an adjustable angle b with respect to the stage plane, and the optical axis of the second industrial camera forms an adjustable angle c with respect to the stage plane, and c > b.

[0010] An illumination unit, arranged in conjunction with the camera, illuminates the core wire solder joints;

[0011] The processing unit is electrically connected to the first industrial camera and the second industrial camera, and is used to acquire images collected under settings b and c and output the weld joint appearance inspection results.

[0012] Preferably, a is 5° to 45°, b is 10° to 60°, and c is greater than or equal to 61° and not exceeding 90°.

[0013] Preferably, the angle-adjustable mounting mechanism includes a pitch adjustment structure with at least one rotating shaft, a scale marking, and a locking mechanism.

[0014] Preferably, the angle-adjustable mounting mechanism is mounted on the two-axis adjustment structure.

[0015] Preferably, the lighting unit is a coaxial light source or a combination of a coaxial light source and a lateral ring light source.

[0016] Preferably, the tilt angle of the platform is set to an obtuse angle or an acute angle relative to the conveying direction.

[0017] Preferably, it further includes a processor and a storage module, which are electrically connected; the storage module stores the parameter weight file and network structure configuration file of the neural network model.

[0018] Preferably, in this text, 'a' is the angle between the stage support surface and the horizontal plane; 'b' and 'c' are the angles between the camera optical axis and the stage plane, and 'c' > 'b'.

[0019] Compared with existing horizontal stage and fixed viewing angle solutions, the present invention has at least the following advantages:

[0020] By combining the stage tilt angle a with the included angles b and c (and c > b) of the dual cameras, geometric decoupling of solder joint reflection, diffuse reflection and shadow is achieved, significantly reducing the specular highlight saturation area and enhancing the visibility of solder joint outline;

[0021] The complementary use of two perspectives enhances the imaging distinguishability of different defects (such as cold solder joints, bridging, pinholes, solder overflow / solder beads, etc.) and reduces false detections and missed detections under a single perspective.

[0022] The scaled / locking adjustable mechanism and two-axis fine adjustment enable rapid and repeatable assembly and formula switching, reducing on-site debugging workload.

[0023] When used in conjunction with coaxial / lateral combined lighting, it forms a stable optomechanical combination, facilitating standardized production line deployment and maintenance. Attached Figure Description

[0024] Figure 1 This is a diagram of the electronic components and solder joints related to the core wire solder joints.

[0025] Figure 2 This is a schematic diagram of the overall machine structure, gantry frame, three-axis platform, conveyor and carrier.

[0026] Figure 3 This is a schematic diagram of the arrangement of the tilting platform array on the conveyor line.

[0027] Figure 4 This is a schematic diagram of the relationship between the dual-camera setup and coaxial illumination.

[0028] Figure 5 This is a block diagram of the control system. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings; it should be understood that these embodiments are only used to illustrate the structural scheme of the present invention, and are not intended to limit the present invention.

[0030] like Figure 1 As shown, the electronic component 100 related to the core wire solder joint is composed of an arc-shaped base 101 and a metal backplate 102. The backplate 102 is fixed to the inside of the base 101 by fastening screws 103. A lead assembly 105 is provided on it, including a metal lead 106 and a transition bend 107 connected to the metal backplate 102. The solder joints to be inspected are mainly located at the root area where the transition bend of the lead 107 meets the terminal block 108, which is a critical solder joint for electrical and mechanical connection.

[0031] Furthermore, this component is used to reliably lead out the internal "core wire" and repeatedly contact / connect it to the external circuit: the arc-shaped base 101 and the metal back plate 102 provide mounting and positioning, the outer edge insulated arc-shaped base 101 serves as electrical isolation and anti-slip limiting, and acts as a conductive contact or test contact to mate with the mating parts. The solder joint at the root undertakes the dual functions of electrical connection and mechanical fixation, ensuring reliable conduction under conditions such as vibration and temperature cycling. This type of structure is commonly used in scenarios such as sensor leads, grounding / shielding leads, detachable electrical connection terminals, and in-circuit test probes.

[0032] After the electronic components are manufactured, they are placed into the testing line. One of the testing processes in the testing line is the visual inspection of the core wire solder joints. The equipment for visual inspection of solder joints is described in detail below.

[0033] The overall testing equipment includes: a platform for supporting the product to be tested, the platform being fixed at an angle a>0 relative to the horizontal plane; an imaging unit including a first industrial camera and a second industrial camera, mounted on an angle-adjustable mounting mechanism, the mounting mechanism being configured such that the optical axis of the first industrial camera forms an adjustable angle b with respect to the platform plane, and the light from the second industrial camera forms an adjustable angle c with respect to the platform plane, where c>b; an illumination unit, arranged in conjunction with the cameras to illuminate the core wire solder joints; and a processing unit connected to the first and second industrial cameras, used to acquire images captured by the cameras at the set angles b and c and output the solder joint appearance inspection results.

[0034] like Figure 2 As shown, this is a device for visually inspecting core wire solder joints. The entire machine consists of left and right support frames 201.

[0035] The gantry base 200 is composed of a support frame 202 (left side) and a support frame 202 (right side). The inner side of the column 203 is machined with a linear module 207 mounting surface and a groove 208. The top is connected by a crossbeam 209 and a cable drag chain bracket 210 and a power distribution box 211 are installed. A two-axis platform 300 is fixed inside the gantry. The X-axis 301 is a roller linear guide on the crossbeam 209, which can be a ball screw or a belt slide, and its stroke covers the entire row of workstations. The Z-axis 304 is a vertical lifting module 305 on the column 203. Both axes 300 are directly connected by servo motors or synchronous belts and equipped with limit origin sensors. The end of the two axes 300 is equipped with an angle adjustable mechanism 401, which includes a pitch pivot 402 and a locking element (not shown in the figure), for mounting the first 405, the second industrial camera 406, and the coaxial light source 407, respectively.

[0036] Optionally, a conveying device 501 is located below the gantry, consisting of an aluminum profile guide rail seat 502, a drive wheel and a driven wheel, a tensioning mechanism, and a roller.

[0037] Furthermore, the two-axis adjustment structure 300 (X–Z linear platform) is fixed within the gantry frame 200 formed by the two side support frames 201 and 202: the X-axis is arranged perpendicular to the conveying direction and is used for positioning across the multi-stage platform 510; the Z-axis moves up and down to set the working distance and focus. At the end of the two-axis adjustment structure 300, there is an end mounting base plate 312, on which two sets of camera mounts 408 are arranged, respectively mounting the first industrial camera 405 and the second industrial camera 406, their lenses 607 and coaxial light sources 407.

[0038] Furthermore, each camera mount 408 employs an adjustable mounting mechanism with an angle of 401: a pitch pivot 402 is provided between the camera mount 408 and the end mounting base 312. The outer side of the pivot 402 is equipped with a fan-shaped scale (0°~90°, 1° interval, not shown in the figure) and an arc-shaped elongated hole of 410. The pitch angle can be adjusted and quickly reproduced through a locking mechanism (such as a hand-tightening locking screw). If necessary, a yaw base (with scale and locking device) is added between the camera mount 408 and the pitch pivot 402 to make small left and right slight tilts, thereby avoiding physical interference between the two cameras and the light source and ensuring that the field of view overlaps in the same solder joint area.

[0039] Through the above mechanism, the optical axis of the first industrial camera 405 can be set to an adjustable angle b (range 10°~60°, usually b≈30° during assembly) relative to the plane of the stage 510 to obtain an overall contour map with a medium incident angle; the optical axis of the second industrial camera 406 can be set to an adjustable angle c (range 61°~90°, usually c≈75°) relative to the plane of the stage 510, and c>b, to enhance the surface details of the solder joints in a close-up scraping manner.

[0040] Furthermore, both cameras are rigidly coaxial with the 407 coaxial light source via coaxial adapters, maintaining optical axis alignment with pitch rotation. If lateral supplementary lighting is required, a ring light source support can be added to the side wall of the camera mount 408 and linked to the scale. A locking screw and positioning pin hole are pre-installed between the camera mount 408 and the end mounting plate 312 to limit the extreme angle and improve repeatability.

[0041] During operation, the X-axis moves the two cameras above the target stage 510. After setting the working distance on the Z-axis, b and c are adjusted to the target values ​​according to the 403 scale (c is always greater than b) and locked by the 404 locking component. The processing unit then acquires two images for weld joint appearance inspection.

[0042] Reference Figure 2 and Figure 3 The conveying device has a fixed platform 510, which is a wedge-shaped base 511 and a support plate 512, or an integral wedge block. The support surface has a fixed tilt angle a > 0 relative to the horizontal. The surface has a replaceable fixed stop block 516 and a vacuum / pressure hole 517 is reserved. The two cameras set the optical axes x1 and x2 to the plane of the platform 510 at angles b and c (c > b) respectively through the angle adjustable mechanism 401. The coaxial light source 407 is rigidly coaxially mounted with the lens.

[0043] In this embodiment, the conveying station is fixed to the pallet of the conveying device 501 by an aluminum alloy base plate 518. Four sets of wedge-shaped bases 511 are equidistantly arranged on the base plate 518 along the conveying direction. A product platform 510 is installed on each wedge base 511. The supporting surface of the product platform 52 forms a fixed tilt angle α > 0 with respect to the horizontal plane; preferably α is 20° (which can be achieved by changing the wedges in stages within the range of 5° to 45°), so that the weld point of the test part faces upward and avoids self-obstruction. The tilt angle of the product platform 510 is set to an acute or obtuse angle relative to the conveying direction, thereby maintaining sufficient field of view margin during conveying in and out and between adjacent product platforms 510, exposing the main reflective surface of the weld point and reducing the obstruction of the line of sight by upstream / downstream workpieces.

[0044] like Figure 2 and Figure 4 As shown, the angle-adjustable mounting mechanism 401 above the stage 510 supports two imaging components: a first industrial camera 405 and a second industrial camera 406. The mounting mechanism 401 adopts the form of a pitch pivot 402 locking element and is connected to the two-axis platform through an end flange, realizing independent setting of the camera position and angle.

[0045] Furthermore, the optical axis of the first industrial camera 405 forms an adjustable angle b relative to the mounting surface of the stage 510, preferably b≈30° (adjustable within the range of 10° to 60°), to acquire an overall appearance image at a medium incident angle; the optical axis of the second industrial camera 406 forms an adjustable angle c relative to the mounting surface of the stage 510, preferably c≈75° (adjustable within the range of 61° to 90°), and satisfies c>b, the first industrial camera 405 enhances the surface details of the solder joints in a close-up scraping manner.

[0046] Furthermore, the fields of view of the two cameras cover the target welding point area in the same stage 510, and the two-axis platform 300 is responsible for positioning the multiple stages 510 according to the beat.

[0047] Furthermore, coaxial light sources 407 are respectively mounted on the front end of the two cameras. The light sources 407 are rigidly coaxial with the telecentric lens 601 through a coaxial adapter (not shown in the figure) and change synchronously with the camera's pitch. The illumination unit is a combination of the 407 coaxial light source or the 407 coaxial light source and the 603 lateral ring light source to highlight the features of the solder joint image.

[0048] The above structure ensures that during continuous conveying on the production line, the workpiece is supported at a fixed tilt angle a, and dual-view imaging (b / c > b) is performed. Furthermore, the tilt direction of the stage 510 is arranged at an acute / obtuse angle with the conveying direction, which effectively reduces obstruction and fully exposes the reflective surface of the weld point.

[0049] Furthermore, each camera and light source assembly includes, from top to bottom, an industrial camera 405 / 406, a coaxial light source module 407, and a telecentric lens 601. The coaxial light source module 407 is rigidly connected to the telecentric lens 601 via a dedicated coaxial adapter. It has a 45° beam splitter 605 inside, which projects the illumination light of the LED array onto the surface being measured along the optical axis of the lens, thereby achieving coaxial geometry where "camera optical axis = illumination optical axis".

[0050] Furthermore, the working distance WD between the telecentric lens 601 and the surface being measured is 220mm ± 20mm. The two light sources are independently powered and PWM-dimmed; the illumination of both camera components is linked to the pitch / yaw of the camera mount 408, ensuring that the coaxial relationship is not disrupted during angle adjustment. To accommodate different solder joint materials, the light source wavelength can be selected from visible green light (approximately 530nm), red light (approximately 625nm), and near-infrared light (approximately 850nm).

[0051] In use, the first and second industrial cameras are respectively aimed at the solder joint area at a relative position on the same stage 510: the coaxial light source 407 provides uniform axial illumination to significantly enhance the contrast between the solder joint surface texture and the solder. After the two cameras are positioned in place on the two-axis platform 300, they are aligned according to the above-mentioned WD = 220 ± 20 mm and coaxial distance.

[0052] The mechanical setting is 40±20mm to acquire images, and the processing unit processes the two images synchronously to obtain stable and complementary weld point image features without changing the attitude of the stage 510.

[0053] like Figure 5 As shown, the processing unit is connected 406 to the first industrial camera 405 and the second industrial camera, and is used to acquire images captured by the cameras at a set angle b and c and output the weld joint appearance inspection results. It also includes a processor 701 and a storage module 702, the processor 701 and the storage module 702 being electrically connected. The storage module 702 stores the parameter weight file and network structure configuration file of the neural network model.

[0054] The processor 701 is electrically connected to the storage module 702; the storage module 702 stores model parameter weight files and network structure configuration files (including version number, input size, preprocessing recipe, class set, and threshold, etc.). The processing unit loads the corresponding "model package" according to the version number upon startup or model change, and can be hot-updated; historical versions and inference logs are retained for traceability and rollback. Weights can be in floating-point or fixed-point quantization form, supporting CPU / GPU / accelerator card inference.

[0055] The processing unit communicates with the light source driver, two-axis platform, and host computer using an industrial controller / IPC. Its workflow is as follows:

[0056] Step 1: Synchronous acquisition of two images, I_b and I_c, is triggered by the encoder / 509 photoelectric positioning signal to achieve simultaneous exposure of the two cameras, resulting in images at angles b and c (c > b). During acquisition, the internal timestamp, lens focal length, light source brightness, and current angle parameters are recorded and written into the image metadata to ensure data traceability.

[0057] Step two involves geometric calibration and normalization. Intrinsic parameters are calibrated for both cameras, and extrinsic parameters are established using the stage plane as a reference. Homography matrices H_b and H_c are calculated from their respective viewpoints to the "510 stage reference plane." H_b and H_c are then expanded to the same top-view coordinate system, achieving pixel-to-millimeter conversion and eliminating perspective errors caused by tilt angles. This ensures that the same solder joint has a consistent ROI and measurement reference in both images.

[0058] Step 3: ROI positioning and preprocessing. The ROI of the solder joint is determined by using the positioning holes / edges or template matching on the fixture; the image is then subjected to brightness equalization, reflection suppression (polarizers or multiple exposure fusion can be superimposed), sharpening, and noise filtering.

[0059] Step 4: The dual-view feature fusion and recognition processing unit loads the neural network model in the storage module: the network consists of two input branches (corresponding to I_b and I_c) and a fusion head, or it can be fused at the result level of two models.

[0060] Feature-level fusion involves extracting two deep features and then concatenating / weighting them by channel to output defect segmentation / detection results (categories such as: cold solder joints, insufficient solder, solder bridging, solder beads / solder beads, pinholes, cracks, oxidation, etc.). It also includes result-level fusion, which generates candidate boxes / masks, biases micro-defects towards I_c with a confidence weight w_c > w_b, and biases morphological boundaries towards I_b, and performs NMS / mask merging.

[0061] Step 5: Based on quantitative indicators such as category threshold, area / length / grayscale gradient, the judgment and output will give the OK / NG judgment, defect type and location size (mm), and the two original images, mask and judgment JSON will be bound to the current workpiece ID and uploaded or archived.

[0062] Through the above design, the processing unit fuses and recognizes the dual-angle images (b, c, and c > b) under a unified geometric reference, taking into account both the overall shape and surface details, thereby stably outputting the appearance inspection results of the core wire solder joints.

[0063] In summary, this embodiment achieves stable, complementary imaging and reliable determination of core wire solder joints by combining a fixed stage tilt angle a > 0, adjustable included angles b and c (and c > b) of dual cameras, and coaxial / lateral cooperative illumination. It should be understood that the above descriptions of structure, dimensions, and parameter ranges are for illustrative purposes only and not for limitation. Without departing from the core concept of this invention, the following can be equivalently replaced or arbitrarily combined: stage shape (integral / split wedge, replaceable), tilt direction (obtuse / acute angle relative to the transport and its orientation), number and arrangement of cameras (single / dual / multiple cameras, baseline and working distance settings), adjustable mechanism type (pitch / yaw / roll, lead screw or worm gear / globoss head, scale and locking method), optical components and bands (telecentric / fixed-focus lens, polarizing / filter, coaxial and ring combination), and processing unit implementation (CPU / GPU / accelerator, model version and quantization accuracy). Changes to engineering details such as the transport method, stage positioning, and interface protocol with MES / PLC do not affect the essence of this invention. Therefore, the above embodiments are only for illustrating the technical solution, and all equivalent substitutions or modifications made according to the claims of this invention should fall within the protection scope of this invention.

Claims

1. A device for visually inspecting core wire solder joints, characterized in that, include: A platform is used to support the product to be tested, and the platform is fixed relative to the horizontal plane at an angle α>0. The imaging unit, including a first industrial camera and a second industrial camera, is mounted on an angle-adjustable mounting mechanism. The mounting mechanism is configured such that the optical axis of the first industrial camera forms an adjustable angle b with respect to the stage plane, and the light from the second industrial camera forms an adjustable angle c with respect to the stage plane. c>b; An illumination unit is arranged in conjunction with the camera to illuminate the core wire solder joints; The processing unit is connected to the first industrial camera and the second industrial camera, and is used to acquire the images captured by the cameras at the angle between set b and c and output the weld appearance inspection results.

2. The core wire solder joint appearance inspection equipment according to claim 1, characterized in that, a is 5°~45°, b is 10°~60°, and c is 61°~90°.

3. The core wire solder joint appearance inspection equipment according to claim 1, characterized in that, The angle-adjustable mounting mechanism includes at least one pitch scale marking and locking mechanism on a rotating shaft.

4. The core wire solder joint appearance inspection equipment according to claim 3, characterized in that, The adjustable mounting mechanism is located on the two-axis adjustment structure.

5. The core wire solder joint appearance inspection equipment according to claim 1, characterized in that, The lighting unit is a coaxial light source or a combination of a coaxial light source and a side ring light source to highlight the features of the solder joint image.

6. The device according to any one of claims 1 to 5, characterized in that, The tilt angle of the stage is set at an obtuse or acute angle to the conveying direction to reduce obstruction and expose the reflective surface of the solder joint.

7. The device according to any one of claims 1 to 5, characterized in that, It also includes a processor and a storage module, the processor being electrically connected to the storage module, the storage module storing parameter weight files and network structure configuration files of the neural network model.

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