A pseudo-coaxial visual laser repair device

Abstract

The present invention discloses a pseudo-coaxial visual laser repair equipment, including a jig motion platform and a laser vision part, wherein the jig motion platform is used to realize the position adjustment of the jig, and the laser vision part is used to capture and repair the product on the jig; the laser vision part includes a laser head and a CCD camera, and the laser emitted by the laser head is coaxial with the visual optical path of the CCD camera after being reflected by a 45° reflector; it is characterized in that the CCD camera is a color CCD camera, the lens of the CCD camera is a telecentric lens, and an annular light source is provided on the upper and lower sides of the 45° reflector, respectively. When repairing the product, the LAB color space of the image is analyzed in combination with the self-developed visual software, the background grayscale of the product is automatically extracted, and the area near the split where the grayscale is higher than the background grayscale and the degree of grayscale increase are identified; then different laser powers are adopted for fixed-point repair in a targeted manner; it has the advantages of high detection accuracy, high repair efficiency and good repair effect.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing equipment, and in particular to a pseudo-coaxial visual laser repair device. Background Art

[0002] Since aluminum alloy has many advantages such as high strength, light weight, strong texture and low price, more and more products in 3C electronic products will choose aluminum alloy as the frame and shell of the product. However, the use of aluminum alloy material also has some disadvantages, especially in products such as mobile phones and tablets that have special requirements for signal reception, it is necessary to eliminate the electrostatic shielding generated by the entire metal frame. Here, an injection molding process is involved - hot injection molding (Insertmolding).

[0003] Hot injection molding is a kind of insert molding, which is a molding method that inserts metal, plastic semi-finished products or other materials into a pre-made mold cavity, and then injects molten plastic material. However, the hot injection molding process is prone to burrs and excess glue problems, which will cause the product to discolor at the junction of metal and injection molding after the anodizing process. In order to solve this problem, the traditional method is to pickle the product and re-oxidize it until the poor color is eliminated. However, solving the discoloration phenomenon through chemical means is not only inefficient and costly, but the waste generated will also cause serious environmental pollution, which greatly limits the promotion and application of chemical treatment processes.

[0004] A Chinese invention patent application with publication number CN 108956615 A ​​discloses a laser surface repair process for the housing of an electronic product, which uses a detection and repair device to detect and repair the electronic product; the detection and repair device includes a CCD camera, a laser marking machine, and a fixed workstation. The invention uses a CCD camera to scan and photograph the housing of the electronic product, uses an image processing method to process the surface image, and then performs defect contours to obtain a marking contour, and then uses a laser marking machine for precise positioning and repair. Although the invention has the characteristics of high efficiency and no pollution to the environment; however, the invention only uses a camera to capture the white spots that appear on the surface of the aluminum part after oxidation, and then performs laser repair; and for the contact between the injection molded part and the aluminum, the specifications of the heterochromatic defects are diverse and the degree of heterochromaticity is also very complicated, and it is difficult to achieve the purpose of repair using the existing laser processing method. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a pseudo-coaxial visual laser repair device with high detection accuracy and the ability to perform targeted repairs according to different colors.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions.

[0007] A pseudo-coaxial visual laser repair equipment, comprising a jig motion platform and a laser vision part, wherein the jig motion platform is used to realize the position adjustment of the jig, and the laser vision part is used to capture and repair the product on the jig; the laser vision part comprises a laser head and a CCD camera, and the laser emitted by the laser head is coaxial with the visual optical path of the CCD camera after being reflected by a 45° reflector; it is characterized in that the CCD camera is a color CCD camera, the lens of the CCD camera is a telecentric lens, and annular light sources are respectively provided on the upper and lower sides of the 45° reflector.

[0008] When the above-mentioned repair equipment is working, it includes the following repair steps: 1) manually clamping the product to be inspected in the fixture, moving the joint of the product to be inspected to the visual light path of the CCD camera through the fixture motion platform, and capturing it through the CCD camera; 2) performing product defect analysis on the captured image to obtain the defect area, the overall grayscale of the defect, and the background grayscale of the defect area; after the defect analysis is completed, the defects are graded and the data is transmitted to the controller; 3) the controller controls the laser power according to the specific defect area, the overall grayscale of the defect, and the background grayscale of the defect area, and accurately repairs the defect area.

[0009] More preferably, the laser vision part includes a Z-axis moving mechanism, and the laser head and the CCD camera are installed on a lifting platform of the Z-axis moving mechanism and are lifted and lowered together with the lifting platform.

[0010] More preferably, the jig motion platform includes an X-axis moving mechanism, a Y-axis moving mechanism, a flipping mechanism, a rotating mechanism and a jig assembled together, the X-axis moving mechanism is used to realize the X-axis movement of the jig, the Y-axis moving mechanism is used to realize the Y-axis movement of the jig, the flipping mechanism is used to realize the pitch angle adjustment of the jig, and the rotating mechanism is used to realize the in-plane rotation of the jig.

[0011] More preferably, in the above repair step 1), the product to be inspected is divided into a number of continuous inspection areas along the seam, and the inspection areas are numbered; when taking pictures, each inspection area is photographed by the CCD camera to generate an image.

[0012] More preferably, the detection areas are of the same shape and size, both of which are 24 mm×18 mm.

[0013] More preferably, in the above-mentioned repair step 2), the defect judgment principle is: setting a contrast critical value for defect judgment, when the overall grayscale of the defect area is higher than the grayscale of the background grayscale and exceeds the contrast critical value, the defect is detected; when judging the defect, a frequency analysis algorithm is used to suppress image noise, and the frequency domain and time domain are combined for processing in image processing.

[0014] More preferably, the contrast threshold is between 10-15.

[0015] More preferably, in the above-mentioned repair step 2), the defect area is measured by placing a calibration plate with a size of 8mm×8mm and an accuracy of 0.001 under the CCD camera to take a picture, and calculating the physical area of ​​a single pixel through the actual physical area and pixel area of ​​the calibration plate; after the defect is captured, the pixel area of ​​the defect is analyzed and then converted into a physical area.

[0016] More preferably, in the above repair step 2), the defect analysis method is: using the LAB color space model, combining the L value with the B value, and then detecting product defects of different colors.

[0017] More preferably, in the above repair step 2), the defect classification method is: classified into five grades AE according to the size of the defect area s.

[0018] Grade A, s≤0.05.

[0019] Grade B, 0.05<s≤0.1.

[0020] Grade C, 0.1<s≤0.2.

[0021] Grade D, 0.2<s≤0.3.

[0022] Grade E, S>0.3.

[0023] Area unit is mm 2 .

[0024] When making grading judgments, if the defect level is within the range of A to D, it is considered that the product can be repaired through reprocessing, and if the defect level is E, the product is considered unqualified.

[0025] The beneficial effects of the present invention are: the discoloration degree and depth caused by anodizing of aluminum alloy products are inconsistent due to product batch and process deviations. The present invention organically combines structures such as a color CCD camera, a telecentric lens, and two annular light sources, and uses self-developed visual software to analyze the LAB color space of the image, automatically extract the background grayscale of the product, and identify the area near the split where the grayscale is higher than the background grayscale, which is the defect to be detected; the defects are classified and the level is determined by the area size and color difference contrast of the detected defects, and then different laser powers can be used for fixed-point repair; it has the advantages of high detection accuracy, high repair efficiency and good repair effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Shown is a schematic structural diagram of the pseudo-coaxial visual laser repair equipment provided by the present invention.

[0027] Figure 2 Shown is a schematic structural diagram of the fixture motion platform.

[0028] Figure 3 Shown is a schematic diagram of the structure of the laser vision part.

[0029] Figure 4 Shown is a schematic diagram of the coaxial optical path.

[0030] Description of Figure Numbers.

[0031] 1: Frame, 2: Fixture motion platform, 3: Laser vision part.

[0032] 2-1: X-axis moving mechanism, 2-2: Y-axis moving mechanism, 2-3: flipping mechanism, 2-4: rotating mechanism, 2-5: fixture.

[0033] 3-1: Z-axis moving mechanism, 3-2: laser head, 3-3: CCD camera, 3-4: lifting platform, 3-5: 45° reflector, 3-6: lens, 3-7: ring light source. DETAILED DESCRIPTION

[0034] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present invention.

[0035] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, "at least" means one or more, unless otherwise clearly and specifically defined.

[0036] In the present invention, unless otherwise specified and limited, the terms "assemble", "connect", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or the two elements can be internally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the invention, unless otherwise specified and limited, a first feature being “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being “above”, “below”, and “above” a second feature includes that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “above”, “below”, and “below” a second feature includes that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] The following is a further description of the specific implementation of the present invention in conjunction with the drawings of the specification, so that the technical solution and its beneficial effects of the present invention are clearer and more explicit. The following description of the embodiments with reference to the drawings is exemplary and intended to explain the present invention, but cannot be understood as limiting the present invention.

[0039] Additional aspects and advantages of the present invention will become apparent from the following description or may be learned by practice of the present invention.

[0040] like Figure 1 As shown, a pseudo-coaxial visual laser repair device includes a frame 1, a fixture motion platform 2 installed on the frame 1, and a laser vision part 3.

[0041] Combination Figure 2As shown, the fixture motion platform 2 includes an X-axis moving mechanism 2-1, a Y-axis moving mechanism 2-2, a flipping mechanism 2-3, a rotating mechanism 2-4 and a fixture 2-5 assembled together. The X-axis moving mechanism 2-1 is used to realize the X-axis movement of the fixture 2-5, the Y-axis moving mechanism 2-2 is used to realize the Y-axis movement of the fixture 2-5, the flipping mechanism 2-3 is used to realize the pitch angle adjustment of the fixture 2-5, and the pitch rotation axis is R1, and the rotating mechanism 2-4 is used to realize the in-plane rotation of the fixture 2-5, and the plane rotation axis is R2.

[0042] In this embodiment, the X-axis moving mechanism 2-1, the Y-axis moving mechanism 2-2, the flipping mechanism 2-3, the rotating mechanism 2-4 and the fixture 2-5 are stacked from bottom to top. Obviously, in some embodiments, those skilled in the art can adjust the stacking position of each part as needed, which is not limited to this embodiment.

[0043] Combination Figure 3 , Figure 4 As shown, the laser vision part 3 includes: a Z-axis moving mechanism 3-1, a laser head 3-2 and a CCD camera 3-3. The laser head 3-2 and the CCD camera 3-3 are installed on the lifting platform 3-4 of the Z-axis moving mechanism 3-1 and are lifted and lowered together with the lifting platform 3-4. The laser emitted by the laser head 3-3 is coaxial with the lens 3-6 of the CCD camera 3-3 after being reflected by a 45° reflector 3-5 (the visual optical path is coaxial), that is, a pseudo-coaxial structure is formed.

[0044] Compared with the existing laser vision device, the laser vision part of the present invention has the following characteristics: 1) The CCD camera 3-3 is a color CCD camera, which can more accurately restore the color difference of the product image, overcoming the problem of insufficient color difference range of ordinary black and white CCD. 2) The lens 3-6 adopts a telecentric lens, and an annular light source 3-7 is provided on the upper and lower sides of the 45° reflector 3-5. In this way, the visual light source has a higher uniformity and can truly reflect the brightness information of the defect.

[0045] The present embodiment provides a pseudo-coaxial laser visual repair device, and its repair method is as follows: 1) Manually clamp the product in the fixture 2-5, and the four axes of X-axis, Y-axis, R1-axis, and R2-axis are linked to move the joint of the product to be inspected (the connection transition between plastic and metal) to the lower end of the lens 3-6, and take a photo through the CCD camera 3-3. 2) Analyze the defects to obtain the defect area, the overall grayscale of the defect, and the background grayscale of the defect area; after the defect analysis is completed, judge the defect level and transmit the data to the controller. 3) According to the specific defect area, the overall grayscale of the defect, and the background grayscale of the defect area, control the laser power to accurately repair the defect area. Cycle in sequence until all defect areas of the product are repaired.

[0046] In the above repair step 1), the product to be inspected is divided into several continuous inspection areas along the joint (the transition between plastic and metal), and the inspection areas are numbered. When taking pictures, a color CCD camera is used to take pictures of each inspection area to generate an image.

[0047] In this embodiment, the size of each detection area is 24*18mm. This can ensure that the visual accuracy is 0.008mm, the pixel area is more than 10 pixels, and the corresponding physical area is 0.001mm 2 Above, and the crawling is stable.

[0048] In the above repair step 2), the defect judgment principle is: set a contrast critical value for defect judgment, such as 12. When the overall grayscale of the defect area is 12 grayscale levels higher than the background grayscale, the defect is detected; the outline of the defect can be accurately located. Specifically, the frequency analysis algorithm is used in defect judgment to greatly suppress image noise. The combination of frequency domain and time domain in image processing can accurately locate the position of the defect and determine the area of ​​the defect.

[0049] It should be noted that the contrast threshold for defect judgment can be appropriately adjusted between 10-15, not limited to the above example. The reason for setting the contrast threshold for defect judgment between 10-15 is that a too small contrast setting will cause over-grasping, and a too large contrast setting will cause the grasped contour to be smaller than the actual contour.

[0050] In the above repair step 2), the defect area is measured by placing a ceramic calibration plate with a size of 8*8mm and an accuracy of 0.001 under the CCD camera to take a photo. The physical area of ​​a single pixel is calculated based on the actual physical area and pixel area of ​​the calibration plate. After the defect is captured, the pixel area is analyzed and then converted into the physical area.

[0051] In the above repair step 2), the defect analysis method is: using the LAB color space model, combining the L value with the B value, it is possible to detect defects in products of different colors, effectively reducing interference from the outside world, such as interference from product reflections, dirt, etc.

[0052] In this embodiment, it is preferred to classify by the physical size of the defect. As shown in Table 1, the defects are divided into five levels of AE according to their physical size. In order to conform to the judgment habits of the human eye, the classification judgment is made according to the recognition effect of the human eye. That is, in the same photographing area, if the distance between two defects is less than 0.35mm, it is regarded as one defect. If the defect level is within the range of A~D, it is considered that the product can be repaired by reprocessing. If the defect level is E, the product is considered unqualified, and if no defects are detected, the product is considered qualified.

[0053] Table 1. Defect level classification table.

[0054] Defect level <![CDATA[Area s / (mm 2 )]]> A S≤0.05 B 0.05＜s≤0.1 C 0.1＜s≤0.2 D 0.2＜s≤0.3 E S＞0.3

[0055] In particular, after the defect information of each inspection area is analyzed, the product information and the corresponding defect information (including the defect area number, defect level, defect area, overall defect grayscale, and background grayscale of the defect area, etc.) are uploaded and saved to the transmission server. In this way, the product defect data can be obtained and queried in the subsequent processes.

[0056] Compared with the prior art, the pseudo-coaxial visual laser repair equipment provided by the present invention has the following advantages: 1) The pseudo-coaxial method is adopted to make the laser light path coincide with the visual light path of the CCD camera after being reflected by the 45° reflective lens, so as to realize the coaxial reading of color difference, coaxial repair of defects and discoloration. Efficient operation mode. 2) The five-axis linkage mechanism is adopted to realize that the five surfaces (including curved surfaces) of the product can be repaired in one clamping. 3) Since the degree and depth of discoloration caused by the anodization of aluminum alloy products are inconsistent due to the deviation of product batches and processes, the present invention analyzes the LAB color space of the image through the independently developed visual software, automatically extracts the background grayscale of the product, and identifies the area near the seam where the grayscale is higher than the background grayscale, which is the defect to be detected; the defects are classified and the level is determined by the area size of the detected defects and the color difference contrast, and then different laser powers can be used for targeted point repair.

[0057] Through the description of the above structure and principle, those skilled in the art should understand that the present invention is not limited to the above specific implementations, and improvements and substitutions based on the present invention using the known technology in the art fall within the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims and their equivalents. Parts not described in the specific implementations are prior art or common knowledge.

Claims

1. A method for repairing the contact between an injection molded part and aluminum, which is implemented by using a pseudo-coaxial visual laser repair device, wherein the pseudo-coaxial visual laser repair device comprises a fixture motion platform and a laser vision part, wherein the fixture motion platform is used to adjust the position of the fixture, and the laser vision part is used to capture and repair the product on the fixture; the laser vision part comprises a laser head and a CCD camera, and the laser emitted by the laser head is coaxial with the visual optical path of the CCD camera after being reflected by a 45° reflector; characterized in that: The CCD camera is a color CCD camera, the lens of the CCD camera is a telecentric lens, and an annular light source is provided on the upper and lower sides of the 45° reflector respectively; The work includes the following repair steps: 1) Manually clamp the product to be inspected in the fixture, move the joint of the product to be inspected to the visual light path of the CCD camera through the fixture motion platform, and capture it through the CCD camera; 2) Perform product defect analysis on the captured images to obtain the defect area, overall defect grayscale, and background grayscale of the defect area; after the defect analysis is completed, the defects are graded and the data is transmitted to the controller; 3) The controller controls the laser power according to the specific defect area, the overall grayscale of the defect, and the background grayscale of the defect area to accurately repair the defect area; In the above repair step 1), the product to be inspected is divided into several continuous inspection areas along the joints, and the inspection areas are numbered; when taking pictures, each inspection area is photographed by the CCD camera to generate an image; each inspection area has the same shape and size, which is 24mm×18mm; In the above repair step 2), the defect judgment principle is: set a contrast critical value for defect judgment, when the grayscale of the defect area as a whole is higher than the grayscale of the background and exceeds the contrast critical value, the defect is detected; the frequency analysis algorithm is used in defect judgment to suppress image noise, and the frequency domain and time domain are combined in image processing; the contrast critical value is between 10-15; In the above repair step 2), the defect area is measured by placing a calibration plate with a size of 8 mm × 8 mm and an accuracy of 0.001 under the CCD camera to take a photo, and calculating the physical area of ​​a single pixel through the actual physical area and pixel area of ​​the calibration plate; after the defect is captured, the pixel area of ​​the defect is analyzed and then converted into a physical area; In the above repair step 2), the defect analysis method is: using the LAB color space model, combining the L value and the B value, and then detecting product defects of different colors; In the above repair step 2), the defect classification method is: according to the size of the defect area s, it is divided into five levels of AE; Grade A, s≤0.05; Class B, 0.05<s≤0.1; Class C, 0.1<s≤0.2; Grade D, 0.2<s≤0.3; E grade, S>0.3; Area unit is mm 2 ; When making grading judgments, if the defect level is within the range of A to D, it is considered that the product can be repaired through reprocessing, and if the defect level is E, the product is considered unqualified.

2. A method for repairing the contact between an injection molded part and aluminum according to claim 1, characterized in that: The laser vision part includes a Z-axis moving mechanism, and the laser head and the CCD camera are installed on a lifting platform of the Z-axis moving mechanism and are lifted and lowered together with the lifting platform.

3. A method for repairing the contact between an injection molded part and aluminum according to claim 1, characterized in that: The fixture motion platform includes an X-axis moving mechanism, a Y-axis moving mechanism, a flipping mechanism, a rotating mechanism and a fixture assembled together, wherein the X-axis moving mechanism is used to realize the X-axis movement of the fixture, the Y-axis moving mechanism is used to realize the Y-axis movement of the fixture, the flipping mechanism is used to realize the pitch angle adjustment of the fixture, and the rotating mechanism is used to realize the in-plane rotation of the fixture.

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