Sputter Measurement System

Abstract

To accurately measure the size of spatter even when the amount of self-light emission of the spatter is low.SOLUTION: A system includes: a camera (30) for taking an image of an observation area including a weld part (6); spotlight sources (10R, 10L) for radiating rays of spot light (21R, 21L) towards a side surface of the observation area viewed from the camera (30); and a control device (100) for measuring the size of spatter (7) on the basis of the image taken by the camera (30).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a technique for measuring spatter generated during welding. [Background technology]

[0002] When welding metals, a phenomenon may occur in which droplets of molten metal (spatter) fly off from the surface of the molten part that melts during welding. Since spatter can reduce the quality of products after welding, it is desirable to suppress the generation of spatter. To do this, it is desirable to first measure the generation of spatter.

[0003] As an example of a device for measuring the occurrence of spatter, for example, JP 2019-188421 A (Patent Document 1) discloses a device that can measure the number of spatters by photographing the welded area with a camera during welding and processing the obtained data into images. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-188421 A Summary of the Invention [Problem to be solved by the invention]

[0005] The spatters scattering from the molten part include not only spatters that emit a lot of light themselves, but also spatters that emit little light themselves. Therefore, if you simply take a picture of the spatters with a camera, you may not be able to capture an image of the spatters that emit little light themselves among the spatters scattering from the molten part, and you may not be able to measure the spatters and their sizes.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has as its object to accurately measure the size of a sputter even when the amount of spontaneous light emitted by the sputter is small. [Means for solving the problem]

[0007] (Item 1) A spatter measurement system according to the present disclosure is a spatter measurement system that measures the size of spatter scattering from a molten part that melts during welding, and includes a camera that takes an image of an observation area including the molten part, a spot light source that irradiates spot light toward the observation area from the side of the observation area as viewed from the camera, and a control device that measures the size of the spatter based on the image taken by the camera.

[0008] (Item 2) The sputter measurement system according to item 1, further comprising a telecentric lens disposed between the molten portion and the camera.

[0009] (Item 3) In the sputter measurement system described in item 2, the position of the molten portion is included in the depth of field range of the telecentric lens, and the system further includes a member that is arranged between the molten portion and the spot light source and has a slit for adjusting the irradiation range of the spot light to the depth of field range of the telecentric lens. Effect of the Invention

[0010] According to the present disclosure, even if the amount of spontaneous light emitted by the sputter is small, the size of the sputter can be measured with high accuracy. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an example of an overall configuration of a sputter measurement system. [Diagram 2] FIG. 1 is a schematic diagram (part 1) showing the measurement principle of sputtering. [Diagram 3] FIG. 2 is a diagram showing an example of an image of an observation area captured by a camera. [Figure 4] FIG. 2 is a schematic diagram (part 2) showing the measurement principle of sputtering. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [System Configuration] 1 is a diagram showing an example of the overall configuration of a sputter measurement system 1 according to this embodiment. Metallic base materials 2 and 3 are welded by a processing laser beam 5 emitted from a laser generator (not shown). The portion irradiated with the laser beam 5 during welding melts to become a molten part 6. By moving the laser generator in the welding advance direction (Y direction in the figure), a weld bead extending in the Y direction in the figure is formed. In the figure, the Y direction indicates the above-mentioned welding advance direction, the Z direction indicates the normal direction of the base materials 2 and 3, and the X direction indicates the direction perpendicular to the Y and Z directions.

[0013] When the base materials 2 and 3 are welded, spatter 7 may fly from the molten part 6. The spatter 7 may degrade the quality of the product after welding. For example, in the case of welding to wire a cell terminal and a bus bar of a storage battery, if the spatter 7 fly, the spatter 7 may attack the resin coating material covering the wiring arranged in the vicinity, causing a short circuit or disconnection of the wiring, or the spatter 7 may adhere between the welding pins of the board arranged in the vicinity, causing a short circuit of the board. Therefore, it is desirable to suppress the generation of the spatter 7 itself, or to confirm that the generation of the spatter 7 does not cause a problem. To do this, it is desirable to first measure the generation of the spatter.

[0014] In consideration of these points, the sputter measurement system 1 according to the present embodiment is configured to measure the size (dimension) of the sputter 7 scattering from the molten part 6. Specifically, the sputter measurement system 1 includes spot light sources 10R and 10L, a camera 30, a telecentric lens 40, and a control device 100.

[0015] The camera 30 captures images of the observation area including the molten part 6 melted by the laser light 5 at high speed. The camera 30 outputs image data obtained by the capture to the control device 100. Note that a blackout curtain 4 that does not reflect light is disposed on the rear side of the observation area as viewed from the camera 30.

[0016] The telecentric lens 40 is disposed in the optical path between the molten part 6 and the camera 30. Unlike an ordinary lens, the telecentric lens 40 is a special lens that can produce light whose main optical axis is parallel to the optical axis of the lens. Due to its optical characteristics, the telecentric lens 40 has a region (hereinafter also referred to as "depth of field region R1") in which the size of the subject image does not change even if the distance between the camera 30 and the subject changes. Therefore, by photographing the spatter 7, which is the subject, with the camera 30 through the telecentric lens 40, as long as the spatter 7 is included in the depth of field region R1 of the telecentric lens 40, the size of the image of the spatter 7 does not change regardless of the position of the spatter 7 (even if the position of the spatter 7 is displaced from the focal position due to scattering), and no image distortion due to parallax occurs.

[0017] The spatters scattering from the molten part 6 include not only spatters with a high amount of spontaneous light but also spatters with a low amount of spontaneous light. Therefore, simply photographing the spatters 7 with the camera 30 may not capture an image of the spatters with a low amount of spontaneous light among the spatters 7 scattering from the molten part 6, and may not be able to measure the spatters and their sizes.

[0018] In consideration of this point, the sputter measurement system 1 according to the present embodiment is provided with spot light sources 10R and 10L. The spot light sources 10R and 10L emit spot light spreading in a cone shape as illumination light for sputter observation. The spot light sources 10R and 10L are disposed at positions facing each other with the molten part 6 in between.

[0019] The spot light source 10R emits spot light toward the right side surface of the observation area including the molten part 6 when viewed from the camera 30. Specifically, the spot light source 10R includes a light source 11R that generates high-luminance light in response to a command from the control device 100, and a light source lens 12R that converts the light generated by the light source 11R into spot light and emits it toward the molten part 6. The optical axis of the light source lens 12R is perpendicular to the optical axis of the camera 30.

[0020] The spot light source 10L emits spot light toward the left side surface of the observation area including the molten part 6 when viewed from the camera 30. Specifically, the spot light source 10L includes a light source 11L that generates high-luminance light in response to a command from the control device 100, and a light source lens 12L that converts the light generated by the light source 11L into spot light and emits it toward the molten part 6. The optical axis of the light source lens 12L is perpendicular to the optical axis of the camera 30.

[0021] The control device 100 includes a central processing unit (CPU) and memories such as a read only memory (ROM) and a random access memory (RAM). During welding of the base materials 2 and 3, the control device 100 operates the spot light sources 10R and 10L to illuminate an observation area including the molten portion 6 from the side with spot light, and measures the size of the spatter 7 scattering from the molten portion 6 based on image data captured by the camera 30 in this state.

[0022] 2 is a diagram showing a schematic diagram of the measurement principle of spatter 7 by the spatter measurement system 1. The measurement of spatter 7 is performed in-process while the base materials 2, 3 are being welded.

[0023] The observation area photographed by the camera 30 includes a depth of field area R1 of the telecentric lens 40, a remote area R2 that is farther from the camera 30 than the depth of field area R1, and a close area R3 that is closer to the camera 30 than the depth of field area R1. The depth of field area R1 is within a range of several mm from the focal position.

[0024] During measurement of the sputter 7, the relative position in the Y direction between the molten portion 6 and the telecentric lens 40 is adjusted so that the molten portion 6 is included in the depth of field region R1 of the telecentric lens 40. Furthermore, the relative position in the Y direction between the molten portion 6 and the light source lenses 12R, 12L is adjusted so that the spot lights 21R, 21L illuminate the observation region including the molten portion 6. Furthermore, in this embodiment, the relative position in the X direction between the molten portion 6 and the light source lenses 12R, 12L or the irradiation angle (spread) of the spot lights 21R, 21L is adjusted so that the irradiation range of the spot lights 21R, 21L approximately matches the depth of field region R1.

[0025] When no spatters 7 are present in the observation area, there is no object illuminated by the spot lights 21R and 21L in the observation area, and only the blackout screen 4 is photographed by the camera 30, so that the entire image of the observation area appears as a dark spot.

[0026] On the other hand, when the sputter 7 is present in the depth of field region R1 of the telecentric lens 40, the spot lights 21R and 21L are irradiated on the left and right side surfaces of the sputter 7, respectively. As a result, diffuse light (scattered light) is generated on the left and right side surfaces of the sputter 7, and the parallel light of the diffused light passing through the telecentric lens 40 is photographed by the camera 30. Therefore, the left and right side shapes of the sputter 7 are photographed as bright spots. That is, in this embodiment, the spot lights 21R and 21L are irradiated on the side surface of the sputter 7 to be measured, and the left and right side shapes of the sputter 7 are photographed by the camera 30. The control device 100 measures the size of the sputter 7 from the side shape of the sputter 7 photographed by the camera 30. As a result, even if the amount of spontaneous light emitted by the sputter 7 is small, the sputter 7 and its size can be measured with high accuracy.

[0027] 3 is a diagram showing an example of an image of the observation region captured by the camera 30. Bright spots 7R and 7L included in the image of the observation region are images of the right and left edge shapes of the sputter 7 present within the depth of field region R1. The control device 100 estimates the overall shape of the sputter 7 from the shapes of the bright spots 7R and 7L, and measures the size (dimensions) of the sputter 7 from the estimated overall shape.

[0028] When the sputter 7 exists within the depth of field region R1 of the telecentric lens 40, the measured size of the sputter is almost constant regardless of the distance of the sputter. Therefore, as long as the sputter 7 exists within the depth of field region R1, the size (dimension) of the sputter 7 can be measured with high accuracy even if the sputter 7 moves due to scattering.

[0029] Returning to Figure 2, if the sputter is present in the remote region R2 or the nearby region R3, the size of the image of the sputter will change depending on the perspective of the sputter (the distance to the camera 30), making it difficult to accurately measure the size of the sputter.

[0030] In view of this, in this embodiment, as described above, the irradiation range of the spot lights 21R and 21L is adjusted so as to substantially match the depth of field region R1. Therefore, the sputters in the remote region R2 and the near region R3 are not illuminated by the spot lights 21R and 21L and are not reflected in the image of the observation region. As a result, the sputters 7 in the remote region R2 and the near region R3, whose image size changes depending on the perspective, are excluded from the target of dimension measurement. Therefore, the measurement accuracy of the sputters 7 is prevented from decreasing.

[0031] As described above, in the sputter measurement system 1 according to the present embodiment, the side surface of the sputter 7 is irradiated with the spot lights 21R and 21L to generate diffuse light (scattered light) on the side surface of the sputter 7, and the diffuse light is photographed by the camera 30 to measure the side surface shape of the sputter 7, and the size of the sputter is measured from the measured side surface shape of the sputter. As a result, even if the amount of spontaneous light emitted by the sputter 7 is small, the size of the sputter 7 can be measured.

[0032] Furthermore, in the sputter measurement system 1 according to the present embodiment, a telecentric lens 40 is disposed between the molten part 6 and the camera 30. Therefore, the size of the sputter can be measured with high accuracy regardless of whether the sputter is close or far away.

[0033] [Variation 1] In the above-described embodiment, the irradiation range of the spot lights 21R and 21L is matched to the depth of field region R1 by adjusting the relative positions in the X direction between the melting portion 6 and the light source lenses 12R and 12L or the irradiation angles of the spot lights 21R and 21L. However, the method of matching the irradiation range of the spot lights 21R and 21L to the depth of field region R1 is not limited to such a method.

[0034] 4 is a diagram showing a schematic diagram of the measurement principle of sputter 7 by sputter measurement system 1A according to this modified example 1. Sputter measurement system 1A is obtained by adding slit plates 50R and 50L to sputter measurement system 1 shown in FIG.

[0035] The slit plate 50R is disposed between the melting portion 6 and the light source lens 12R, and has a slit 51R for adjusting the irradiation range of the spot light 21R to the depth of field region R1 of the telecentric lens 40.

[0036] The slit plate 50L is disposed between the melting portion 6 and the light source lens 12L, and has a slit 51L for adjusting the irradiation range of the spot light 21L to the depth of field region R1 of the telecentric lens 40.

[0037] In this manner, the slit plates 50R, 50L may be disposed between the melted portion 6 and the light source lenses 12R, 12L, so that the irradiation ranges of the spot lights 21R, 21L may coincide with the depth of field region R1.

[0038] [Variation 2] In the above embodiment, the left and right side surfaces of the sputter are illuminated by two spot light sources 10R and 10L, but one spot light source may be used to illuminate either the left or right side surface of the sputter. Even in this case, it is possible to measure the shape of either the left or right side surface of the sputter, estimate the overall shape of the sputter 7 from the measured side shape, and measure the size of the sputter 7 from the estimated overall shape.

[0039] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0040] 1,1A sputter measurement system, 2,3 base material, 4 black curtain, 5 laser light, 6 melted part, 7 sputter, 7L,7R bright spot, 10L,10R spot light source, 11L,11R light source, 12L,12R light source lens, 21L,21R spot light, 30 camera, 40 telecentric lens, 50L,50R slit plate, 51L,51R slit, 100 control device, R1 depth of field area, R2 remote area, R3 close area.

Claims

1. A spatter measurement system for measuring the size of spatter scattered from a molten part that melts during welding, A camera that captures an image of an observation area including the molten part; a spot light source that irradiates spot light toward the observation area from a side of the observation area when viewed from the camera; and a control device that measures the size of the sputters based on the image taken by the camera.

2. The sputter metrology system of claim 1 , further comprising a telecentric lens disposed between the melt portion and the camera.

3. The position of the molten portion is included in the depth of field range of the telecentric lens, The sputter measurement system according to claim 2 , further comprising a member disposed between the molten portion and the spot light source, the member having a slit for adjusting an irradiation range of the spot light to a depth of field range of the telecentric lens.

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