FPC busbar ultrasonic welding appearance detection equipment and detection method thereof

Abstract

The invention belongs to the technical field of visual detection, and particularly relates to FPC busbar ultrasonic welding appearance detection equipment and a detection method thereof. The equipment comprises a rack of which the upper surface is provided with a detection station, and a carrier material conveying mechanism which is arranged on the upper surface of the rack along the Y-axis direction and is used for horizontally conveying a carrier material loaded with a to-be-detected workpiece, the image optical detection mechanism is used for projecting detection light with a preset rule to the upper surface of the to-be-detected workpiece and obtaining a light reflection path of the upper surface of the to-be-detected workpiece, and the three-axis driving mechanism is arranged on the upper surface of the conveying rack and used for driving the optical detection mechanism to move in the X-axis direction, the Y-axis direction and the Z-axis direction. The background control system is used for generating a standard comparison image in the database and outputting a detection result according to the comparison condition of the light reflection image and the standard comparison image; the device is simple in overall structure and low in cost, and the recognition precision and the working efficiency are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of visual inspection, and in particular to an FPC busbar ultrasonic welding appearance inspection device and an inspection method thereof. Background Art

[0002] The principle of ultrasonic metal welding is a special method of connecting the same or different metals by using the mechanical vibration energy of ultrasonic frequency (over 16KHz). When ultrasonic welding metal workpieces, neither current nor high-temperature heat source is applied to the workpieces. It only converts the wire frame vibration energy into friction work, deformation energy and limited temperature rise between the workpieces under static pressure. The metallurgical bonding between the joints is a solid-state welding achieved without melting the parent material. Therefore, it effectively overcomes the spatter and oxidation phenomena generated during resistance welding.

[0003] Ultrasonic welding machines can perform single-point welding, multi-point welding and short strip welding on thin wires or thin sheet materials of non-ferrous metals such as copper, silver, aluminum, and nickel. At present, ultrasonic welding is mostly used for the busbar FPC of new energy vehicle batteries on the market. However, due to the extremely small size and thickness of the FPC connection end, perforation problems are prone to occur during the welding process. This situation can be easily solved by the existing visual recognition system, but for defects such as too small weld spots, warping of welding edges, and welding failure, since the detection camera shoots the positive projection image of the workpiece vertically downward, it is not possible to better capture the warping situation, resulting in frequent judgment failures in the actual production process, resulting in the quality of the outbound workpieces cannot be guaranteed. At present, for this problem, the general practice in the industry is to add the next station to confirm through manual inspection, but this undoubtedly increases labor costs and reduces production efficiency. Therefore, in view of the shortcomings of the existing technology, it is urgent to design an ultrasonic welding appearance inspection equipment for FPC busbars to meet production needs. Summary of the invention

[0004] The object of the present invention is to provide an FPC busbar ultrasonic welding appearance detection device and a detection method thereof to solve the problems raised in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: an FPC busbar ultrasonic welding appearance detection device, comprising:

[0006] A frame, the upper surface of which is provided with a detection station;

[0007] A material conveying mechanism is disposed on the upper surface of the frame along the Y-axis direction and is used for horizontally conveying a carrier loaded with workpieces to be inspected;

[0008] An optical detection mechanism, used to project a normal projection and an oblique projection detection light onto the upper surface of the workpiece to be detected, and to obtain a normal projection image and an oblique projection image of the upper surface of the workpiece to be detected;

[0009] A three-axis driving mechanism is provided on the upper surface of the conveyor frame and is used to drive the optical detection mechanism to move in the XYZ axis direction;

[0010] The background control system is used to generate a first standard comparison chart and a second standard comparison chart corresponding to the orthographic projection image and the oblique projection image in the database respectively, and output the detection result according to the comparison between the orthographic projection image and the first standard chart and between the oblique projection image and the second standard chart.

[0011] The FPC busbar ultrasonic welding appearance inspection device of the present invention comprises at least two optical inspection mechanisms which are arranged side by side along the direction of the X-axis to achieve repeated inspection of the upper surface of the workpiece to be inspected.

[0012] The FPC busbar ultrasonic welding appearance inspection device described in the present invention, wherein the three-axis drive mechanism includes a Z-axis drive module that drives the optical inspection mechanism to move up and down, an X-axis drive module that drives the Z-axis drive module to move horizontally, and a Y-axis drive module that drives the X-axis drive module to move horizontally; the optical inspection mechanism is mounted on the movable terminal of the Z-axis drive module.

[0013] The FPC busbar ultrasonic welding appearance inspection equipment of the present invention is characterized in that a carrier reflux mechanism is also provided at the bottom of the frame, and both the carrier reflux mechanism and the material conveying mechanism are chain conveyor lines.

[0014] The FPC busbar ultrasonic welding appearance inspection device described in the present invention, wherein the optical inspection mechanism includes a detection camera arranged vertically downward, and an annular light source arranged horizontally directly below the detection camera; the detection camera is coaxial with the annular light source.

[0015] The FPC busbar ultrasonic welding appearance inspection equipment described in the present invention, wherein the annular light source includes a first light bar that radiates divergent light downward, and a second light bar that radiates vertical surface light downward; four of the first light bar and the second light bar are provided and are connected end to end to form a regular square structure, the four second light bars are located on the inner side of the four first light bars, and the light emitting direction of the second light bar is inclined toward the optical axis of the inspection camera.

[0016] In addition, to achieve the above-mentioned purpose, the present invention also provides the following technical solution: a method for ultrasonic welding appearance detection of FPC busbar, the method comprising the following steps:

[0017] With the first light bar lit as a first detection state, obtaining an orthographic projection image of the workpiece to be detected and comparing it with the first standard comparison image to output a first detection result;

[0018] With the first light bar off and the second light bar on as the second detection state, obtaining the oblique projection image of the workpiece to be detected and comparing it with the second standard comparison image to output a second detection result;

[0019] Output a final detection result based on the comparison between the first detection result and the second detection result.

[0020] In the FPC busbar ultrasonic welding appearance inspection method of the present invention, the step of outputting the first inspection result specifically includes:

[0021] Taking the edge contour of the workpiece to be inspected as the first boundary, taking the first boundary as the reference and extending K length units equidistantly in the circumferential direction to form a second boundary, taking the second boundary as the detection range to obtain the orthographic projection image of the workpiece to be inspected, wherein K is greater than zero;

[0022] Calculating a corresponding first grayscale histogram and a corresponding first standard grayscale histogram according to the orthographic projection image of the workpiece to be inspected;

[0023] Whether the workpiece to be inspected has defects is determined based on the comparison between the first grayscale histogram and the first standard grayscale histogram.

[0024] The FPC busbar ultrasonic welding appearance inspection method of the present invention, wherein, in the second inspection state, the Y-axis direction is used as the first inspection direction, a first oblique side image of the workpiece to be inspected with the second boundary as the inspection range is obtained, and a second grayscale histogram of the first oblique side image is calculated;

[0025] In the second detection state, taking the X-axis direction as the second detection direction, acquiring a second oblique side image of the workpiece to be detected with the second boundary as the detection range, and calculating a third grayscale histogram of the second oblique side image;

[0026] Whether the workpiece to be inspected has defects is determined based on the comparison between the second grayscale histogram and the corresponding second standard grayscale histogram, or based on the comparison between the third grayscale histogram and the corresponding third standard grayscale histogram.

[0027] The FPC busbar ultrasonic welding appearance inspection method of the present invention, wherein the step of outputting the final inspection result specifically includes:

[0028] If the average grayscale value of the second grayscale histogram is greater than the average grayscale value of the corresponding second standard grayscale histogram, then outputting a final inspection result for determining whether the workpiece to be inspected has a defect; or,

[0029] If the average grayscale value of the third grayscale histogram is greater than the average grayscale value of the corresponding third standard grayscale histogram, a final inspection result for determining whether the workpiece to be inspected has a defect is output.

[0030] Compared with the prior art, the present invention has the following beneficial effects: the present invention has a simple overall structure, requires minimal modification to the equipment, and thus has low costs; it can also greatly improve recognition accuracy and work efficiency, and is more conducive to production and processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is an overall structural diagram of the FPC busbar ultrasonic welding appearance detection equipment of the present invention.

[0033] Figure 2 for Figure 1 A magnified view of the local structure.

[0034] Figure 3 for Figure 2 A magnified view of the local structure.

[0035] Figure 4 The figure is a principle diagram of the detection optical path of the FPC busbar ultrasonic welding appearance detection device of the present invention.

[0036] Figure 5 The present invention is a flowchart of the steps of the FPC busbar ultrasonic welding appearance detection method. DETAILED DESCRIPTION

[0037] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present invention and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0038] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] "Multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0040] Moreover, the terms "up, down, left, right, upper end, lower end, longitudinal" and the like indicating directions are all based on the posture and position of the device or equipment described in this solution during normal use.

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following will be described clearly and completely in combination with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are partial embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0042] Embodiment 1

[0043] This embodiment discloses Figures 1 to 4 The FPC busbar ultrasonic welding appearance inspection device shown includes a frame 10, which is a cubic structure. An inspection station is provided on the upper surface of the frame 10 for installing various modules or mechanisms;

[0044] The device further comprises a material conveying mechanism 20, which is arranged on the upper surface of the frame 10 along the Y-axis direction and is used to horizontally convey a carrier loaded with workpieces to be inspected;

[0045] The device also includes an optical detection mechanism 30, which is used to project the detection light of the positive projection and the oblique projection to the upper surface of the workpiece to be detected, and obtain the positive projection image and the oblique projection image of the upper surface of the workpiece to be detected;

[0046] The device also includes a three-axis driving mechanism 40, which is disposed on the upper surface of the conveyor frame 10 and is used to drive the optical detection mechanism 30 to move in the XYZ axis direction;

[0047] The device also includes a background control system (not shown), which is used to generate a first standard comparison chart and a second standard comparison chart corresponding to the orthographic projection image and the oblique projection image in the database, respectively, and output a detection result according to the comparison between the orthographic projection image and the first standard chart and the oblique projection image and the second standard chart;

[0048] By setting two different modes of light for separate detection, the direct projection image is detected in a conventional way to ensure the initial detection effect, and the oblique projection image is further used to detect the warped edge of the workpiece to be inspected. When a warped edge appears, the corresponding oblique projection image is different from the overall or local grayscale of the normal oblique projection image. At this time, it can be reversely judged that the workpiece has a warped welding edge defect, and the recognition accuracy can reach an error rate of 1 / 1000. Compared with traditional detection methods, the accuracy is not only greatly improved, but also the production process nodes and additional labor costs are directly saved, and the degree of equipment modification can be basically ignored, and the cost of equipment can be further reduced, which is more beneficial to the production and operation of the enterprise.

[0049] In this embodiment, at least two optical detection mechanisms 30 are provided and arranged side by side along the X-axis direction to realize repeated detection of the upper surface of the workpiece to be detected. Two detections in the same direction can be realized, and four reciprocating bidirectional detections can further improve the detection accuracy. The number of detections can be selected according to actual needs.

[0050] In this embodiment, the three-axis drive mechanism 40 includes a Z-axis drive module 41 for driving the optical detection mechanism 30 to move up and down, an X-axis drive module 42 for driving the Z-axis drive module 41 to move horizontally, and a Y-axis drive module 43 for driving the X-axis drive module 42 to move horizontally; the optical detection mechanism 30 is mounted on the movable terminal of the Z-axis drive module 41 through an installation frame, and a linear adjustment module 50 for high-precision adjustment of the X-axis position of the optical detection mechanism 30 is further installed on the mounting frame; specifically, the Z-axis drive module 41, the X-axis drive module 42 and the Y-axis drive module 43 can all be implemented by linear motors or screw modules, and of course other linear mechanisms such as motor rack guide modules can also be used.

[0051] In this embodiment, a carrier reflux mechanism 60 is further provided at the bottom of the frame 10. The carrier reflux mechanism 60 and the material conveying mechanism 20 are both chain conveyor lines, so as to realize the rapid reflux of the carrier and ensure the efficiency of production and processing.

[0052] In this embodiment, the optical detection mechanism 30 includes a detection camera 31 arranged vertically downward, and a ring light source 32 arranged horizontally just below the detection camera 31; the detection camera 31 is coaxial with the ring light source 32; specifically, the ring light source 32 includes a first light bar 321 irradiating divergent light downward, and a second light bar 322 irradiating vertical planar light downward; that is, the light of the second light bar 322 forms a vertical planar light in space, and when projected onto the upper surface of the workpiece, forms a long and thin line light spot; the first light bar 321 and the second light bar 322 are each provided with four light spots that are aligned end to end. The four second light bars 322 are located on the inner side of the four first light bars 321, and the light emitting direction of the second light bars 322 is inclined toward the optical axis of the detection camera 31, that is, the angle between the plane formed by the light emitted by the second light bars 322 and the horizontal plane is less than 90 degrees, so that the two groups of second light bars 322 opposite to each other on the left and right and front and back can scan the upper surface of the workpiece twice in succession when they reciprocate in the corresponding horizontal directions. When the edge of the workpiece is warped, the warped edge will cut off the reflection of the light of the second light bar 322, so that the defect can be quickly identified.

[0053] Embodiment 2

[0054] This embodiment is basically the same as the first embodiment, and the similarities are not repeated here. The difference is that this embodiment also discloses Figure 5 The FPC busbar ultrasonic welding appearance detection method shown is applied to the device in Example 1. Specifically, the method includes the following steps:

[0055] Step S1: The first light bar 321 is lit as the first detection state, so that the appearance contour of the workpiece is sufficiently clear, thereby obtaining an orthographic projection image of the workpiece to be detected and obtaining a first detection result;

[0056] Step S2: The first light bar 321 is turned off and the second light bar 322 is turned on as the second detection state, so that the influence of ambient light on the scanning of the second light bar 322 is reduced in this state, and the oblique projection image of the workpiece to be detected is obtained and the second detection result is obtained;

[0057] Step S3: Outputting the final detection result through the background control system according to the comparison between the first detection result and the second detection result;

[0058] Wherein, outputting the first detection result specifically includes the following steps:

[0059] The edge contour of the workpiece to be inspected is taken as the first boundary, and the first boundary is used as the reference to extend K length units equidistantly in the circumferential direction to form the second boundary, and the orthographic projection image of the workpiece to be inspected is obtained with the second boundary as the detection range, wherein K is greater than zero. In actual production, K is generally taken as an integer within 5-10mm to ensure that the image range obtained is large enough, so that when the second light bar 322 is irradiated obliquely, its surface light can be reflected in other directions or blocked from entering the detection camera 31, thereby forming a signal-free triggering feedback to the detection camera 31. Compared with the traditional detection method of only using vertical downward orthographic projection, the detection effect is better and more comprehensive;

[0060] Acquire a corresponding first grayscale histogram according to the orthographic projection image of the workpiece to be inspected;

[0061] Whether the workpiece to be inspected has defects is determined based on the comparison between the first grayscale histogram and the first standard grayscale histogram.

[0062] Furthermore, outputting the second detection result specifically includes the following steps:

[0063] In the second detection state, taking the Y-axis direction as the first detection direction, acquiring a first oblique side image of the workpiece to be detected with the second boundary as the detection range, and calculating a second grayscale histogram of the first oblique side image;

[0064] In the second detection state, taking the X-axis direction as the second detection direction, acquiring a second oblique side image of the workpiece to be detected with the second boundary as the detection range, and calculating a third grayscale histogram of the second oblique side image;

[0065] Whether the workpiece to be inspected has defects is determined based on the comparison between the second grayscale histogram and the corresponding second standard grayscale histogram, or based on the comparison between the third grayscale histogram and the corresponding third standard grayscale histogram.

[0066] Furthermore, outputting the final detection result specifically includes the following steps:

[0067] If the average grayscale value of the second grayscale histogram is greater than the average grayscale value of the corresponding second standard grayscale histogram, then a final inspection result for determining whether the workpiece to be inspected has a defect is output; or,

[0068] If the average grayscale value of the third grayscale histogram is greater than the average grayscale value of the corresponding third standard grayscale histogram, a final inspection result for determining whether the workpiece to be inspected has defects is output.

[0069] That is to say, when there is warping at the edge of the workpiece, the second light bar moves horizontally toward the workpiece from a direction away from the workpiece. Due to the inclined angle between the surface light and the upper surface of the carrier, when the light approaches the workpiece, the reflected light will be blocked by the warped part of the workpiece and cannot be reflected into the detection camera. A light constraint chamber is formed under the warped part of the workpiece. At this time, the detection camera can capture the image information of this part, that is, the darkness of this part increases, and thus the warping defect of the workpiece can be reversely known through the grayscale histogram.

[0070] Specific as Figure 4 As shown, the emitted light A1 of the second light bar 322 is reflected by the upper surface of the carrier when moving from left to right and enters the lower surface of the warped part of the workpiece 100 to form a secondary downward reflected light A1', resulting in the reflected light A1" that would normally enter the inside of the detection camera 31 being unable to enter the inside of the detection camera. At this time, the grayscale value corresponding to the warped part of the workpiece will surge, resulting in a peak in the grayscale histogram, and then it can be reversely judged that the workpiece has a warping defect; if the workpiece does not have a warping defect, it is as if the light A2 and A2' enter the detection camera normally. In this case, the welding of the workpiece is normal and the grayscale value will not change.

[0071] In addition, in practice, in order to more quickly see the presence of warping defects in the workpiece from the histogram, the contour of the workpiece can be divided into multiple parts in the same direction and mapped to multiple continuous areas on the horizontal axis of the histogram in turn. When a peak appears in a certain area of ​​the histogram, it can be known that the workpiece being tested has an edge warping defect.

[0072] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. An FPC busbar ultrasonic welding appearance inspection device, characterized in that: include: A frame, the upper surface of which is provided with a detection station; A material conveying mechanism is disposed on the upper surface of the frame along the Y-axis direction and is used for horizontally conveying a carrier loaded with workpieces to be inspected; An optical detection mechanism, used to project a normal projection and an oblique projection detection light onto the upper surface of the workpiece to be detected, and to obtain a normal projection image and an oblique projection image of the upper surface of the workpiece to be detected; A three-axis driving mechanism is provided on the upper surface of the conveyor frame and is used to drive the optical detection mechanism to move in the XYZ axis direction; The background control system is used to generate a first standard comparison chart and a second standard comparison chart corresponding to the orthographic projection image and the oblique projection image in the database respectively, and output the detection result according to the comparison between the orthographic projection image and the first standard chart and between the oblique projection image and the second standard chart.

2. The FPC busbar ultrasonic welding appearance inspection equipment according to claim 1 is characterized in that: At least two optical detection mechanisms are provided and arranged side by side along the X-axis direction to achieve repeated detection of the upper surface of the workpiece to be detected.

3. The FPC busbar ultrasonic welding appearance inspection equipment according to claim 2 is characterized in that: The three-axis driving mechanism includes a Z-axis driving module for driving the optical detection mechanism to move up and down, an X-axis driving module for driving the Z-axis driving module to move horizontally, and a Y-axis driving module for driving the X-axis driving module to move horizontally; The optical detection mechanism is mounted on the movable terminal of the Z-axis driving module.

4. The FPC busbar ultrasonic welding appearance inspection equipment according to claim 2 is characterized in that: A carrier reflux mechanism is also provided at the bottom of the frame, and both the carrier reflux mechanism and the material conveying mechanism are chain conveying lines.

5. The FPC busbar ultrasonic welding appearance inspection equipment according to claim 2 is characterized in that: The optical detection mechanism comprises a detection camera arranged vertically downward, and an annular light source arranged horizontally directly below the detection camera; the detection camera is coaxial with the annular light source.

6. The FPC busbar ultrasonic welding appearance inspection equipment according to claim 5 is characterized in that: The annular light source includes a first light bar that radiates divergent light downward, and a second light bar that radiates vertical surface light downward; four of the first light bar and four of the second light bar are provided and are connected end to end to form a regular square structure, the four second light bars are located on the inner side of the four first light bars, and the light emitting direction of the second light bar is inclined toward the optical axis of the detection camera.

7. A method for detecting the appearance of ultrasonic welding of FPC busbars, according to the FPC busbar ultrasonic welding appearance detection device according to claim 6, characterized in that: The method comprises the following steps: With the first light bar lit as a first detection state, obtaining an orthographic projection image of the workpiece to be detected and comparing it with the first standard comparison image to output a first detection result; With the first light bar off and the second light bar on as the second detection state, obtaining the oblique projection image of the workpiece to be detected and comparing it with the second standard comparison image to output a second detection result; Output a final detection result based on the comparison between the first detection result and the second detection result.

8. The FPC busbar ultrasonic welding appearance detection method according to claim 7 is characterized in that: The step of outputting the first detection result specifically includes: Taking the edge contour of the workpiece to be inspected as the first boundary, taking the first boundary as the reference and extending K length units equidistantly in the circumferential direction to form a second boundary, taking the second boundary as the detection range to obtain the orthographic projection image of the workpiece to be inspected, wherein K is greater than zero; Calculating a corresponding first grayscale histogram and a corresponding first standard grayscale histogram according to the orthographic projection image of the workpiece to be inspected; Whether the workpiece to be inspected has defects is determined based on the comparison between the first grayscale histogram and the first standard grayscale histogram.

9. The FPC busbar ultrasonic welding appearance detection method according to claim 8, characterized in that: The step of outputting the second detection result specifically includes: In the second detection state, taking the Y-axis direction as the first detection direction, acquiring a first oblique side image of the workpiece to be detected with the second boundary as the detection range, and calculating a second grayscale histogram of the first oblique side image; In the second detection state, taking the X-axis direction as the second detection direction, acquiring a second oblique side image of the workpiece to be detected with the second boundary as the detection range, and calculating a third grayscale histogram of the second oblique side image; Whether the workpiece to be inspected has defects is determined based on the comparison between the second grayscale histogram and the corresponding second standard grayscale histogram, or based on the comparison between the third grayscale histogram and the corresponding third standard grayscale histogram.

10. The FPC busbar ultrasonic welding appearance detection method according to claim 9, characterized in that: The steps to output the final test results specifically include: If the average grayscale value of the second grayscale histogram is greater than the average grayscale value of the corresponding second standard grayscale histogram, then outputting a final inspection result for determining whether the workpiece to be inspected has a defect; or, If the average grayscale value of the third grayscale histogram is greater than the average grayscale value of the corresponding third standard grayscale histogram, a final inspection result for determining whether the workpiece to be inspected has a defect is output.

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