TW202426903A - Apparatus and method for inspecting surface defect - Google Patents

Abstract

The present disclosure relates to an apparatus and method for inspecting a surface defect. The apparatus for inspecting a surface defect on an inspection object while the inspection object is being conveyed may include: a conveyor configured to provide an inspection object to a conveyor roller; a laser inspection section configured to generate an electrical signal indicating a surface condition of the inspection object by emitting a laser to at least one surface of the inspection object and receiving reflected waves while the inspection object is conveyed in a longitudinal direction on the conveyor roller and passes through an inspection region; and a control device configured to analyze the electrical signal indicating the surface condition of the inspection object and determine whether the inspection object is suitable or unsuitable.

Description

Apparatus and method for detecting surface defects

[Cross-reference to related applications]

This application is based on Korean Patent Application No.10-2022-0181926 filed with the Korean Intellectual Property Office on December 22, 2022, the disclosure of which is incorporated herein by reference in its entirety.

The present invention relates to an apparatus and method for detecting surface defects. Specifically, the present invention relates to an apparatus and method for automatically detecting surface defects of an object to be detected, such as a drawn material of a linear motion guide.

With known surface defect detection methods, it is possible to detect surface defects from an object having a simple cross-sectional shape such as a tube or a round rod by eddy current detection, ultrasonic detection, and the like. In eddy current detection, when the object to be detected has a shape, the eddy current detection coil must be manufactured to be suitable for the shape of each rod, and even in this case when the coil is offset from the detection surface by a certain distance, the number of channels increases and portions such as corners cannot be detected. In the case of ultrasonic detection, the probe must be manufactured and replaced depending on the shape of the rod of the shape to be detected, and because a medium such as water must be present, detection reliability is achieved only when the medium is in contact with the entire shape of the rod of the shape to be detected. Therefore, there is a problem that it is very expensive and difficult to administer and perform ultrasound testing.

In the case where the object to be inspected has a shape, a known magnetic particle inspection method can be applied. However, even in the case of magnetic particle inspection, defects must be detected by bringing a medium into contact with the object to be inspected and passing a current through the object, and an additional process (such as inspection using the naked eye or a visual camera) is required.

Another learning method for detecting surface defects of shape bars is to configure a visual camera to have multiple channels and automatically detect when a defect (such as a scratch) occurs on a surface having a continuous and constant pattern. However, in this method, a surface brightness difference depending on the distance or angle of light irradiating the object to be inspected may be identified as a defect, or stains or foreign matter on the surface may be identified as a defect. In addition, since a learning function for a program configured for various types of defects needs to be additionally provided, a defect type not identified in the program may not be accurately identified. In addition, unlike a system in which the size of a defect is limited as in eddy current testing or ultrasonic testing and a defect in an object to be tested that exceeds a certain limit is excluded as an unsuitable object to be tested, in the case of using a visual camera, since the size of a defect cannot be automatically measured or the measurement is limited, there is the inconvenience of having to additionally check the size of the defect.

Furthermore, when performing visual inspection of an object to be inspected, multiple inspection operators manually rotate a shape material as the object to be inspected, and inspect the surface or edge of the shape material by using light and a magnifying glass. In this case, the defect detection capability and inspection time vary depending on the condition and skill level of the operator, and there is a high possibility that defects will be overlooked and not accurately identified.

Linear motion guides, which are used as guides for tool transport in automated production lines and automatic machine tools in the semiconductor, display, and smartphone manufacturing processes, should guide the components and instruments to be transported with high precision. Therefore, in linear motion guides, dimensional accuracy is important, and surface defects are not allowed because they interfere with the precise transport of the components or instruments being transported.

The present invention discloses an apparatus and method for automatically and accurately inspecting surface defects of an object to be inspected (which may be referred to as an "inspection object"), such as a drawing material of a linear motion guide.

First, the features disclosed in the present invention can be summarized as follows. In view of the foregoing, according to one aspect disclosed in the present invention, a surface defect detection device for detecting a surface defect of a detection object while the detection object is being transported may include: a conveyor, which is configured to provide a detection object to a conveyor roller; a laser detection section, which is configured to generate an electrical signal indicating a surface condition of the detection object by: while the detection object is being transported on the conveyor roller in a longitudinal direction and passing through a detection area, a laser is emitted to at least one surface of the detection object and a reflected wave is received; and a control device, which is configured to analyze the electrical signal indicating the surface condition of the detection object and determine whether the detection object is suitable or unsuitable.

The conveyor roller for the detection of the detection area may include: a vertical guide roller, which is configured to perform vertical movement of the vertical alignment guide of the detection object under the control of the control device; and a horizontal guide roller, which is configured to perform horizontal movement of the horizontal alignment guide of the detection object under the control of the control device.

At least one pair of vertical guide rollers and at least one pair of horizontal guide rollers may be arranged before and after the positioning of the detection area.

The surface defect inspection apparatus may include a brush and a blower, which are sequentially arranged at the front end of the laser inspection section in a conveying direction to remove foreign matter from the surface of the inspection object under the control of the control device.

The surface defect inspection apparatus may include a first marker configured to mark an inspection identification symbol on the inspection object under the control of the control device when the inspection object is placed on the conveyor roller by the conveyor.

The surface defect inspection apparatus may include a second marker disposed at the rear end of the laser inspection section and configured to mark a defect position on the inspection object under the control of the control device.

The control device may be configured to calculate a size of a defect in the surface condition of the inspection object and provide the calculated size to a display device.

The surface defect detection equipment may further include an object carrier, which is configured to load a plurality of detection objects, wherein the control device is configured to control the object carrier to provide the plurality of detection objects one by one to the conveyor, and control the conveyor to place the detection objects received by the conveyor on the conveyor roller.

The surface defect detection equipment may include: a suitable object carrier, which is configured to load the detection objects determined to be suitable; and an unsuitable object carrier, which is configured to load the detection objects determined to be unsuitable, wherein the control device is configured to: control the second conveyor to transport and load the detection objects determined to be suitable one by one onto the suitable object carrier; and control the second conveyor to transport and load the detection objects determined to be unsuitable one by one onto the unsuitable object carrier.

The laser detection section may include a plurality of laser sensors, each of which includes a laser transmitter and a laser receiver and is configured to generate the electrical signal, wherein the laser sensors may include: an upper laser sensor and a lower laser sensor, which are configured to respectively detect the surface conditions of the top surface and the bottom surface of the detection object; and one or more side surface laser sensors, which are configured to detect a surface condition of one or more chamfered surfaces, flat surfaces, or an inclined surface between two flat surfaces, wherein the chamfered surfaces, the flat surfaces, and the inclined surface are formed between the top surface and the bottom surface of the detection object.

At least one of the side laser sensors is disposed on each of the left side and the right side relative to the longitudinal direction of the detection object.

The side laser sensors may include: a first laser sensor configured to detect a surface condition of a region including an upper chamfered surface of the detection object; a second laser sensor configured to detect a surface condition of a region including a lower chamfered surface of the detection object; and a third laser sensor configured to detect a surface condition of an extended flat surface, a concave flat surface, and an inclined surface existing between the upper chamfered surface and the lower chamfered surface, wherein the extended flat surfaces extend from the chamfered surfaces respectively, and the inclined surfaces are provided between the extended surfaces and the concave flat surfaces.

According to another aspect disclosed in the present invention, a surface defect detection method for detecting a surface defect by a control device, wherein the control device controls a surface defect detection equipment for detecting a detection object while the detection object is being transported. The surface defect detection method may include the following steps: under the control of the control device, the detection object is transported on a conveyor roller in a longitudinal direction; under the control of the control device, an electrical signal indicating a surface condition of the detection object is generated by emitting a laser to at least one surface of the detection object and receiving a reflected wave while the detection object is passing through a detection area; and under the control of the control device, the detection object is determined to be suitable or unsuitable by analyzing the electrical signal indicating the surface condition of the detection object.

In the step of generating the electrical signal, a plurality of laser sensors are used, each of which includes a laser transmitter and a laser receiver to generate the electrical signal, wherein the plurality of laser sensors may include: an upper laser sensor and a lower laser sensor, which are configured to detect the surface conditions of the top surface and the bottom surface of the detection object, respectively; and one or more side surface laser sensors, which are configured to detect a surface condition of one or more chamfered surfaces, flat surfaces, or an inclined surface between two flat surfaces, wherein the chamfered surfaces, the flat surfaces, and the inclined surface are formed between the top surface and the bottom surface of the detection object.

By using the surface defect detection apparatus and method according to the present disclosure, the apparatus is configured into multiple channels to include laser measurement sensors corresponding to respective formed surfaces to detect defects on the surface of the detection object, and is capable of automatically detecting the surface defects and measuring the size of the defects while the detection object is transported to the laser measurement sensors configured as described above. Specifically, the surface defect detection method of the present disclosure can easily detect surface defects even on drawn materials or the like that do not have a simple shape in cross section, such as a linear motion guide that promotes linear reciprocating motion in a facility such as an automated production line or a machine tool.

That is, for example, when defects are detected on the final surface of a drawn shape material on a linear motion guide after drawing, heat treatment, and calibration procedures, a laser measurement method is used to detect surface defects instead of an operator's visual inspection of each formed surface, so that the location and size of the defects can be automatically measured regardless of the shape or condition of the surface, a decision can be made as to whether the drawn shape material is suitable or unsuitable, and the drawn shape material can be separated and discharged.

Utilizing the surface defect detection apparatus and method according to the present disclosure, it is possible to prevent operator errors by applying an automatic detection method using laser measurement, to achieve intermediate measurement after drawing by connecting to the processes before and after the drawing of the drawn shaped material, and to achieve online control for remote control and detection, thereby promoting improved productivity.

Hereinafter, the disclosure will be described in detail with reference to the accompanying drawings. In this article, similar components in each figure are represented by similar element symbols, if possible. In addition, the detailed description of known functions and/or configurations will be omitted. In the following description, the necessary components for understanding the operation according to various embodiments will be mainly described, and the description of components that may confuse the essence of this specification will be omitted. In addition, some components in the drawings may be exaggerated, omitted, or schematically drawn. The size of each component does not fully reflect the actual size, and therefore the description provided herein is not limited by the relative size or spacing of the components drawn in each of the drawings.

When describing the embodiments of the present disclosure, when it is determined that a detailed description of known technologies related to the present disclosure may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. In addition, the terms described later are defined in consideration of the functions in the present invention and may vary according to the intention, habit, or the like of the user or operator. Therefore, the definition of the terms should be made based on the description throughout this specification. The terms used in the detailed description are only used to describe the embodiments of the present invention and should not be regarded as limiting. Unless otherwise expressly used, the singular form of the expression includes the meaning of the plural form of the expression. In this specification, expressions such as “including” or “comprising” are intended to indicate any features, numbers, steps, operations, elements, or some or combinations thereof, and should not be interpreted as excluding the existence or possibility of one or more other features, numbers, steps, operations, elements, or some or combinations thereof.

In addition, terms such as “first” and “second” may be used to describe various components, but the components are not limited by the terms and these terms are used only for the purpose of distinguishing one component from another.

FIG. 1 is a schematic plan view of a surface defect detection device 100 according to an embodiment of the present invention.

1 , according to one embodiment of the present invention, a surface defect detection device 100 for detecting a detection object 1 during transportation includes: object carriers 3, 3-1, 31, 32, 33; a conveyor 4; a brush 7; a blower 8; a laser detection section 12; a first marker 6; a second marker 13; a conveyor 14; suitable object carriers 15, 15-1; unsuitable object carriers 16, 16-1; and a control device 50.

The control device 50 may be operated as hardware (such as a semiconductor processor), software (such as an application), or a combination thereof to perform overall control of the above components. The control device 50 may include a display device (not shown) for displaying the overall operation procedure of the above components while the surface defect detection device 100 performs surface defect detection on the detection object 1; and may include a memory (not shown) for storing information about the detection process and the results of the detection object 1 while performing surface defect detection, and providing corresponding data in response to a user's query request at a later time. The control device 50 may be a computer device or a personal computer (PC).

FIG. 2 shows an example of a perspective view of the detection object 1 in FIG. 1 .

2 , the inspection object 1 to be subjected to surface defect inspection in the surface defect inspection device 100 according to one embodiment of the present disclosure may include a variant drawn material, a drawn material, or the like that does not have a simple cross-sectional shape, such as a linear motion guide that promotes straight reciprocating motion in a facility such as an automated production line or a machine tool. The inspection object 1 may be made of iron or non-iron metal (including alloy steel), and may be made of various materials that may be considered as a variant drawn material or a drawn material depending on the purpose.

For example, as will be described below with reference to FIG. 4 , the detection object 1 may include a top surface d1, a bottom surface d2, and side surfaces between the top surface d1 and the bottom surface d2, and the side surfaces may include: one or more chamfered surfaces f1, g1, f2, and g2; flat surfaces 61, 63, 65, 71, 73, and 75; or inclined surfaces 62, 64, 72, and 74 each formed between two adjacent flat surfaces. The flat surfaces 61, 63, 65, 71, 73, and 75 in the respective left and right side surfaces may include one or more flat surfaces 63 and 73 due to one or more concave-convex shapes; and one or more flat surfaces 61, 65, 71, and 75 extending between the upper chamfered surfaces f1, g1, f2, and g2 from the upper chamfered surfaces f1, g1, f2, and g2. In the drawings, the left side surfaces f1, e1, g1 and the right side surfaces f2, e2, and g2 between the top surface d1 and the bottom surface d2 are symmetrical to each other, but are not limited thereto. The left side surfaces f1, e1, g1 and the right side surfaces f2, e2, and g2 may be asymmetrical, and each side surface may include shapes such as an inclined surface, a flat surface, and a curved surface.

In the surface defect detection device 100 according to one embodiment of the present disclosure, the laser detection section 12 includes laser sensors configured into multiple channels corresponding to respective formed surfaces to detect surface defects of the detection object 1. The laser sensors configured in this way can automatically detect surface defects and measure the sizes of the surface defects while continuously transporting the detection object 1.

For this purpose, the conveyor 4 may be configured to provide the detection object 1 to the conveyor roller 5. The laser detection section 12 may be configured to generate an electrical signal indicating the surface condition of the detection object 1 by emitting a laser to at least one surface of the detection object 1 and receiving a reflected wave while the detection object 1 is being transported on the conveyor roller 5 in the longitudinal direction and passing through the detection area 9. The control device 50 may be configured to determine whether the detection object 1 is suitable or unsuitable by analyzing the electrical signal indicating the surface condition of the detection object 1. The conveyor roller 5 may include rollers arranged on a conveying path at predetermined distance intervals to transport the detection object 1 in a vertical direction.

First, a procedure for placing the test object 1 from the object carrier 3, 3-1, 31, 32, 33 onto the conveyor roller 5 via the conveyor 4 so as to inspect the test object 1 by the surface defect inspection device 100 according to one embodiment of the present invention will be described.

3A to 3D are views showing a process of placing the test object 1 from the object carrier 3 , 3 - 1 , 31 , 32 , 33 of FIG. 1 onto the conveyor roller 5 via the conveyor 4 .

First, referring to FIG3A , the object carrier 3, 3-1, 31, 32, 33 includes a first support member 3, a second support member 3-1, a loading platform 33 disposed between the first support member 3 and the second support member 3-1, an actuator 31 that performs piston movement to move the loading platform 33 upward and downward, and a pusher 32. The object carrier 3, 3-1, 31, 32, 33 can be arranged on either the left side or the right side perpendicular to the conveying direction of the inspection object 1 on the conveyor roller 5, and can be arranged to automatically perform surface defect inspection with respect to more inspection objects 1 on the loading platform 33. The control device 50 can control the object loaders 3, 3-1, 31, 32, 33 to provide the plurality of test objects 1 loaded on the loading platform 33 to the conveyor 4 one by one, and can control the conveyor 4 to place the test objects 1 provided to the conveyor 4 on the conveyor roller 5.

First, the test object 1 (e.g., a variant drawn material or drawn material) is pre-loaded on the loading platform 33 in a unit of a bundle 2 (e.g., 16 pieces). In order to provide the test object 1 to the conveyor 4, the loading platform 33 is first moved upward and downward by the actuator 31 under the control of the control device 50 to adjust the height of the top test object 1 of the bundle 2, so that one test object 1 can be moved laterally by the force of the pusher pushing one side of the top test object 1 of the bundle. In this case, the test object 1 can be provided to the top surface of the conveyor 4 via the top surface of the second support member 3-1. As shown in FIG. 1 , the detection object 1 can be provided by the second support member 3 - 1 disposed at a plurality of locations and a plurality of conveyors 4 through the top surface of the second support member 3 - 1 at the plurality of locations so as to span over the top surface of the conveyor 4 .

Next, as shown in FIG. 3B , under the control of the control device 50 , the conveyor 4 disposed between the rollers of the conveyor roller 5 can move in the lateral direction along the conveying guide 34 , and at this time, the detection object 1 on the top surface of the conveyor 4 can be positioned directly above the rollers of the conveyor roller 5 .

Next, as shown in FIG. 3C , under the control of the control device 50 , the top surface of the conveyor 4 can be lowered by the actuator, and thus the test object 1 can be placed on the roller of the conveyor roller 5 .

Next, as shown in FIG3D , under the control of the control device 50, the inspection object 1 on the conveyor roller 5 is transported in a straight line along the conveying path to undergo surface defect inspection, and the conveyor 4 moves along the conveying guide 34 toward the second support member 3-1 to receive the next inspection object 1 again. Thereafter, the top surface of the conveyor 4 can be raised by the actuator so that the top surface of the conveyor 4 becomes close to the top surface of the second support member 3-1 or is preferably aligned with the top surface of the second support member 3-1.

At the same time, as shown in Figure 1, when the conveyor 4 provides the detection object 1 to the conveyor roller 5, the laser detection section 12 can be configured to generate an electrical signal indicating the surface condition of the detection object 1 in the following manner: while the detection object 1 is being transported on the conveyor roller 5 in the longitudinal direction and passing through the detection area 9, the laser is emitted to at least one surface of the detection object 1 and the reflected wave is received.

For this purpose, under the control of the control device 50, when the detection object 1 is first placed on the conveyor roller by the conveyor 4, the first marker 6 can mark the detection object 1 with a predetermined detection identification symbol on the detection object 1. At this time, after the detection object 1 is conveyed so that the end of the detection object 1 on the side of the first marker 6 is conveyed to approach the first marker 6, the first marker 6 can mark the predetermined detection identification symbol (for example, a QR code or barcode identification symbol) on the end surface (or its peripheral surface) of the detection object 1. Marking can be performed in various ways, including labeling, printing, and laser marking.

When the marking is completed in this way, the conveyor roller 5 is operated under the control of the control device 50, and the detection object 1 on the conveyor roller 5 moves along the conveying path, and foreign matter is removed from one end of the detection object 1 to the other end by the brush 7 and the blower 8. For example, while passing through the brush 7 and the blower 8 sequentially arranged at the front end of the laser detection section 12 in the conveying direction, the entire front, left, right, and rear surfaces of the detection object 1 are brushed by the brush 7 and blown away by the wind from the blower 8, so that the foreign matter. After being brushed, it can be removed by blowing wind by the blower 8.

After the foreign matter is removed as described above, the laser detection section 12 may be configured to generate an electrical signal indicating the surface condition of the detection object 1 by emitting laser light to at least one surface of the detection object 1 and receiving reflected waves while the detection object 1 is transported in the longitudinal direction on the conveyor roller 5 and passes through the detection area 9. The control device 50 may be configured to determine whether the detection object 1 is suitable or unsuitable by analyzing the electrical signal indicating the surface condition of the detection object 1.

The vertical guide rollers 10 and 10-1 and the horizontal guide rollers 11 and 11-1 may be arranged in pairs before and after the position of the detection area 9. The vertical guide rollers 10 and 10-1 and the horizontal guide rollers 11 and 11-1 are provided to be accurately aligned in the vertical and horizontal directions before detection by the laser detection section 12. Preferably, the vertical guide rollers 10 and 10-1 and the horizontal guide rollers 11 and 11-1 are arranged in pairs before and after the position of the detection area 9, and may be arranged only on one side of the detection area 9 in some cases. The vertical movement of the vertical guide rollers 10 and 10 - 1 for guiding the vertical alignment of the inspection object 1 can be controlled under the control of the control device 50 , and the horizontal movement of the horizontal guide rollers 11 and 11 - 1 for guiding the horizontal alignment of the inspection object 1 can be controlled under the control of the control device 50 .

Fig. 4 is a view showing the laser sensors of the laser inspection section 12 of Fig. 1. In Fig. 4, for convenience, a plurality of laser sensors 121-1, 121-2, 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 are shown as being placed on respective planes extending from the cross section of the inspection object 1. When the laser sensors are placed in this manner, interference between laser signals may result in inaccurate defect analysis. Therefore, preferably, multiple laser sensors 121-1, 121-2, 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 can be placed at different positions on the conveying path of the detection object 1 (i.e., on the left and right sides of the conveyor roller 5), and can even be placed at different positions on the same side.

4, the laser detection section 12 may include a plurality of laser sensors 121-1, 121-2, 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2. Each of the laser sensors 121-1, 121-2, 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 may include a laser transmitter and a laser receiver, which generate an electrical signal by emitting a laser at a pre-installed position and receiving a reflected wave. That is, the laser transmitter is capable of emitting a laser at a predetermined power, and the laser receiver is capable of receiving a wave reflected from a corresponding position of the detection object 1, and generating an electrical signal indicating the surface condition of the detection object 1. The control device 50 may be configured to determine whether the detection object 1 is suitable or unsuitable by analyzing an electrical signal indicating the surface condition of the detection object 1. For example, when the detection object 1 is determined to have defects (such as cracks, pits, deep scratches, depressions (notches), surface overlap, and metal or non-metal foreign matter impact), the detection object may be determined to be unsuitable. More specifically, when the control device 50 compares the electrical signal received from the laser sensor with a signal used as a predetermined reference for the corresponding surface of the detection object 1, and the unsuitable portion having a difference greater than a threshold value may be determined to have defects (such as cracks, pits, deep scratches, depressions (notches), surface overlap, and metal or non-metal foreign matter impact). If at least a portion of the test object 1 has a defect indicating a difference greater than a threshold, the control device 50 may determine that the test object 1 is unsuitable. Otherwise, the control device 50 may determine that the test object 1 is suitable.

The laser detection section 12 may include: a top laser sensor 121-1 and a bottom laser sensor 121-2, which are respectively used to detect the surface conditions of the top surface d1 and the bottom surface d2 of the detection object 1; and one or more side laser sensors 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2, which are respectively used to detect the surface conditions of one or more chamfered surfaces f1, g1, f2, and g2, flat surfaces 61, 63, 65, 71, 73, and 75, and inclined surfaces 62, 64, 72, and 74 formed between two adjacent flat surfaces in the side surfaces between the top surface and the bottom surface of the detection object 1.

At least one of the side laser sensors 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 may be disposed on each of the left and right sides of the detection object 1 in the longitudinal direction.

For example, as shown in Figure 4, the detection object 1 may include a top surface d1, a bottom surface d2, and side surfaces between the top surface d1 and the bottom surface d2, and the side surfaces may include: one or more chamfered surfaces f1, g1, f2, and g2; flat surfaces 61, 63, 65, 71, 73, and 75; or inclined surfaces 62, 64, 72, and 74 each formed between two adjacent flat surfaces. That is, the flat surfaces 61, 63, 65, 71, 73, and 75 in the respective left and right surfaces may include one or more flat surfaces 63 and 73 due to one or more concave-convex shapes; and one or more flat surfaces 61, 65, 71, and 75 extending between the upper chamfered surfaces f1, g1, f2, and g2 from the upper chamfered surfaces f1, g1, f2, and g2. In the drawings, the left surfaces f1, e1, g1 and the right surfaces f2, e2, g2 between the top surface d1 and the bottom surface d2 are symmetrical to each other, but are not limited thereto. The left side surfaces f1, e1, g1 and the right side surfaces f2, e2, g2 may be asymmetrical, and each side surface may include shapes such as an inclined surface, a flat surface, and a curved surface.

Therefore, the owners of the side laser sensors 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 do not always need to be provided, and depending on the shape of each of the left and right surfaces, the side laser may be placed only on the left side in the longitudinal direction of the detection object 1. However, even if one side surface includes only a flat surface, the laser sensor for the flat surface is preferably placed on the side.

In order to facilitate the detection of surface defects on a deformed drawn material, such as a linear motion guide that facilitates straight reciprocating motion in a facility such as an automated production line or a machine tool, the test object 1 may have a shape such as that shown in FIG. 4 .

For this purpose, the side laser sensors 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 may include on at least one of the left and right sides: a first laser sensor 123-1 or 123-2, which is used to detect the surface condition of an area including the chamfered surface f1 or f2 on the detection object 1; and a second laser sensor 124-1 or 124-2, which is used to detect the surface condition of an area including the chamfered surface g1 or g2 below the detection object 1. In addition, the side laser sensors 122-1, 122-2, 123-1, 123-2, 124-1, and 124-2 may include a third laser sensor 122-1 or 122-2 on at least one of the left and right sides, which are used to detect the following surface conditions: extended flat surfaces 61 and 65 or 71 and 75 existing between the chamfered surface f1 or f2 and the lower chamfered surface g1 or g2 on the detection object 1 and extending from the respective edges; concave flat surface 63 or 73; and inclined surfaces 62 and 64 or 72 and 74 between the extended flat surfaces 61 and 65 or 71 and 75 and the concave flat surface 63 or 73.

The control device 50 may be configured to determine whether the detection object 1 is suitable or unsuitable by analyzing an electrical signal indicating the surface condition of the detection object 1 and received from the laser sensor of the laser detection section 12. For example, when the control device 50 compares the electrical signal received from the laser sensor with a signal used as a predetermined reference of the corresponding surface of the detection object 1, and an unsuitable portion having a difference greater than a threshold value may be determined to have a defect (such as a crack, a pit, a depression (notch), a surface layer overlap, and a metallic or non-metallic foreign matter impact). A predetermined application may be used to make such a decision by the control device 50, and if necessary, a deep learning model learned by a system (software) that learns a deep learning model for operating and evaluating defects may be used.

6A to 6C show examples of actual measurement of step or similar surface defect conditions of the test object 1 of FIG1. FIG6A and FIG6B illustrate a groove with a width and depth of 1 mm or less produced by a depression (notch) or the like, and FIG6C illustrates a step with a width and depth of 1 mm or less produced on the surface due to a scratch, a surface layer overlap, a foreign body impact, or the like.

When there is a defect (such as the above-mentioned scratch, indentation (notch), overlapping of the surface layer, or impact of metallic or non-metallic foreign matter), the control device 50 can calculate the size of the defect (such as width, depth, or height) as shown in Figures 6A and 6C, and provide the calculated size to a display device (such as an LCD or LED). The control device 50 can store in a memory statistical data about whether the object 1 is suitable or unsuitable during the above-mentioned detection process, information about whether the equipment is operating normally, or results (such as defect size), and can provide the corresponding data to the display device at the user's query request in the future.

In FIG. 1 , the control device 50 can determine whether the detection object 1 that has passed through the laser detection section 12 in the detection area is suitable or unsuitable, and make the detection object 1 pass through the second marker 13 .

The second marker 13 is disposed at the rear end of the laser detection section 12, and when the detection object 1 is inappropriate due to the presence of a defect, the second marker 13 makes a defect location of the detection object 1 under the control of the control device 50. As shown in FIG5, the second marker 13 can mark an identification symbol (for example, component numbers such as 91, 92, 93, 94, 95, 96 and 97...) at the location where a defect (crack, pit, deep scratch, depression (notch), surface overlap, or metal or non-metal foreign matter impact) exists. Marking can be performed in various ways, including labeling, printing (for example, paint printing, etc.), laser marking, and the like.

As shown in Figure 1, a surface defect detection device 100 according to one embodiment of the present disclosure may include: a detection suitable object carrier 15, 15-1, which is used to load the detection object 1 determined as suitable by the control device 50; and a detection unsuitable object carrier 16, 16-1, which is used to load the detection object 1 determined as unsuitable by the control device 50.

For example, the control device 50 can control the (multiple) second conveyor 14 to convey and load the detection objects 1 determined to be suitable one by one onto the detection suitable object carriers 15, 15-1, and can control the (multiple) second conveyor 14 to convey and load the detection objects 1 determined to be unsuitable one by one onto the detection unsuitable object carriers 16, 16-1. The loading operations of the (multiple) second conveyor 14, the detection suitable object carriers 15, 15-1, and the detection unsuitable object carriers 16, 16-1 can be performed in the opposite order to the operations of the (multiple) conveyor 4 and the object carriers 3, 3-1 shown in Figures 3A to 3D.

As described above, the surface defect detection device 100 according to the present disclosure is configured into multiple channels to include laser measurement sensors corresponding to respective formed surfaces to detect defects on the surface of the detection object 1, and is capable of automatically detecting the surface defects and measuring the size of the defects while conveying the detection object 1 to the laser measurement sensors configured as described above. Specifically, the surface defect detection method of the present disclosure can easily detect surface defects even on a drawn material or the like that does not have a simple shape in cross section, such as a linear motion guide that promotes linear reciprocating motion in a facility (such as an automated production line or a machine tool). That is, for example, when defects are detected on the final surface of a drawn shape material on a linear motion guide after drawing, heat treatment, and calibration procedures, a laser measurement method is used to detect surface defects instead of the operator's visual inspection of each formed surface, so that the position and size of the defects can be automatically measured regardless of the shape or condition of the surface, a decision can be made as to whether the drawn shape material is suitable or unsuitable, and the drawn shape material can be separated and discharged.

The surface defect inspection device 100 according to the present disclosure can prevent operator errors by applying an automatic inspection method using laser measurement, realize intermediate measurement after drawing by connecting to the processes before and after drawing of a shaped material, and realize online control for remote control and inspection, thereby promoting improved productivity.

As described above, the present disclosure has been described based on specific details (such as specific components, limited embodiments, and drawings), but these are provided only to help understand the present disclosure more generally, and the present disclosure is not limited to the above-mentioned embodiments. A person with ordinary knowledge in the technical field to which the present disclosure belongs can make various modifications and changes without departing from the essential characteristics of the present disclosure. Therefore, the spirit of the present disclosure should not be limited to the embodiments, and not only the scope of the attached patent application, but all technical concepts that are equivalent to the scope of the patent application or equivalent modifications to the scope of the patent application should also be interpreted as being included in the scope of the present disclosure.

1: Detection object 2: Bundle 3: Object carrier; first support 3-1: Object carrier; second support 4: Conveyor 5: Conveyor roller 6: First marker 7: Brush 8: Blower 9: Detection area 10: Vertical guide roller 10-1: Vertical guide roller 11: Horizontal guide roller 11-1: Horizontal guide roller 12: Laser detection section 13: Second marker 14: Conveyor; second conveyor 15: Suitable object carrier 15-1: Suitable object carrier 16: Unsuitable object carrier 16-1: Unsuitable object carrier 31: Object carrier; actuator 32: Object carrier; pusher 33: Object carrier; loading platform 34: Conveyor guide 50: Control device 61: Flat surface 62: Inclined surface 63: Flat surface; Concave flat surface 64: Inclined surface 65: Flat surface 71: Flat surface 72: Inclined surface 73: Flat surface; Concave flat surface 74: Inclined surface 75: Flat surface 100: Surface defect detection device 121-1: Laser sensor; Top laser sensor 121-2: Laser sensor; Bottom laser sensor 122-1: Laser sensor; Side laser sensor 122-2: Laser sensor; Side laser sensor 123-1: laser sensor; side laser sensor 123-2: laser sensor; side laser sensor 124-1: laser sensor; side laser sensor 124-2: laser sensor; side laser sensor d1: top surface d2: bottom surface e1: left surface e2: right surface f1: chamfered surface; left surface f2: chamfered surface; right surface g1: chamfered surface; left surface g2: chamfered surface; right surface

The accompanying drawings are included as part of the implementation method to help understand the disclosure of the present invention, provide an embodiment of the present invention, and together with the implementation method illustrate the technical spirit of the present invention, wherein: [Figure 1] is a schematic plan view of a surface defect detection device according to an embodiment of the present invention; [Figure 2] shows an example of a perspective view of the detection object of Figure 1; [Figure 3A] to [Figure 3D] are views showing the process of placing the detection object from the object carrier of Figure 1 on the conveyor roller via the conveyor of Figure 1; [Figure 4] is a view showing a laser sensor in the laser detection section of Figure 1; [Figure 5] shows an example of marking surface defects such as scratches occurring in the detection object 1 of Figure 1; and [Figure 6A] to [Figure 6C] show examples of actual measurement of the step or similar surface defect conditions of the test object 1 in Figure 1.

100: Surface defect detection device

1: Detection object

2: Bundle

3: Object loader; first support

3-1: Object carrier; second support

4:Conveyor

5: Conveyor roller

6: First marker

7: Brush

8: Blower

9: Detection area

10-1: Vertical guide roller

11-1: Horizontal guide roller

12: Laser detection section

13: Second marker

14: conveyor; second conveyor

15: Suitable object carrier

16: Inappropriate object carrier

16-1: Inappropriate object carrier

50: Control device

Claims (14)

A device for detecting a surface defect on a test object while the test object is being transported, the device comprising: a conveyor configured to provide a test object to a conveyor roller; a laser detection section configured to generate an electrical signal indicating a surface condition of the test object by: emitting a laser to at least one surface of the test object and receiving a reflected wave while the test object is being transported on the conveyor roller in a longitudinal direction and passing through a detection area; and a control device configured to analyze the electrical signal indicating the surface condition of the test object and determine whether the test object is suitable or unsuitable. The device of claim 1, wherein the conveyor roller in the detection area comprises: a vertical guide roller configured to perform vertical movement of the detection object for vertical alignment guidance under the control of the control device; and a horizontal guide roller configured to perform horizontal movement of the detection object for horizontal alignment guidance under the control of the control device. As in the apparatus of claim 2, at least one pair of vertical guide rollers and at least one pair of horizontal guide rollers are arranged before and after one of the positioning areas of the detection area. The device of claim 1 further comprises: A brush and a blower, which are sequentially arranged at the front end of the laser detection section in a conveying direction to remove foreign matter from the surface of the detection object under the control of the control device. The device of claim 1 further comprises: A first marker configured to mark a detection identification symbol on the detection object under the control of the control device when the detection object is placed on the conveyor roller by the conveyor. The device of claim 1 further comprises: A second marker, which is arranged at the rear end of the laser detection section and is configured to mark a defect position on the detection object under the control of the control device. An apparatus as claimed in claim 1, wherein the control device is configured to calculate a size of a defect in the surface condition of the inspection object and provide the calculated size to a display device. The device of claim 1 further comprises: an object loader configured to load a plurality of test objects, wherein the control device is configured to control the object loader to provide the plurality of test objects to the conveyor one by one, and control the conveyor to place the test objects received by the conveyor on the conveyor roller. The device of claim 1 further comprises: a suitable object carrier configured to load the test objects determined to be suitable; and an unsuitable object carrier configured to load the test objects determined to be unsuitable, wherein the control device is configured to: control a second conveyor to transport and load the test objects determined to be suitable one by one onto the suitable object carrier; and control the second conveyor to transport and load the test objects determined to be unsuitable one by one onto the unsuitable object carrier. The device of claim 1, wherein the laser detection section includes a plurality of laser sensors, each of which includes a laser transmitter and a laser receiver and is configured to generate the electrical signal, and wherein the laser sensors include: an upper laser sensor and a lower laser sensor, which are configured to detect the surface conditions of the top surface and the bottom surface of the detection object, respectively; and one or more side surface laser sensors, which are configured to detect a surface condition of one or more chamfered surfaces, flat surfaces, or an inclined surface between two flat surfaces, wherein the chamfered surfaces, the flat surfaces, and the inclined surface are formed between the top surface and the bottom surface of the detection object. As in the apparatus of claim 10, at least one of the side laser sensors is disposed on each of the left side and the right side relative to the longitudinal direction of the detection object. The device of claim 10, wherein the side laser sensors include: a first laser sensor configured to detect a surface condition of a region including an upper chamfered surface of the detection object; a second laser sensor configured to detect a surface condition of a region including a lower chamfered surface of the detection object; and a third laser sensor configured to detect a surface condition of an extended flat surface, a concave flat surface, and an inclined surface existing between the upper chamfered surface and the lower chamfered surface, wherein the extended flat surfaces extend from the chamfered surfaces respectively, and the inclined surfaces are provided between the extended flat surfaces and the concave flat surfaces. A method for detecting a surface defect by a control device, wherein the control device controls a surface defect detection device for detecting a detection object while the detection object is being transported, the method comprising: Under the control of the control device, the detection object is transported on a conveyor roller in a longitudinal direction; Under the control of the control device, an electrical signal indicating a surface condition of the detection object is generated by emitting a laser to at least one surface of the detection object and receiving a reflected wave while the detection object is passing through a detection area; and Under the control of the control device, the detection object is determined to be suitable or unsuitable by analyzing the electrical signal indicating the surface condition of the detection object. The method of claim 13, wherein in the generation of the electrical signal, a plurality of laser sensors are used, each of which includes a laser transmitter and a laser receiver to generate the electrical signal, wherein the plurality of laser sensors include: an upper laser sensor and a lower laser sensor, which are configured to detect the surface conditions of the top surface and the bottom surface of the detection object, respectively; and one or more side surface laser sensors, which are configured to detect a surface condition of one or more chamfered surfaces, flat surfaces, or an inclined surface between two flat surfaces, wherein the chamfered surfaces, the flat surfaces, and the inclined surface are formed between the top surface and the bottom surface of the detection object.

Images