JP2007263671A - Coating inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating inspection device capable of easily and accurately inspecting a defective product by extracting the film forming irregularity of the coating, which is applied to the surface of the tip used in the edge of a tool, with high precision. <P>SOLUTION: The coating inspection device has an illuminator 24 for irradiating the surface of the work 12 being the tip used in the edge of the tool with illumination light, a prism body 22 composed of a pair of prisms 18 and 19 for permitting the illumination light of the illuminator 24 and the half mirror 20 positioned in the prism body 22 and is equipped with a support part 16 for supporting a work 12, the reflection plate 14 positioned on the back side of the work 12 and having an reflecting surface 14a for irregularly reflecting the illumination light, a camera 26 for photographing the work 12 illuminated by the illuminator 24 through the prism body 22 and an image processor 30 for extracting the photographed image 38 of the work 12 photographed by the camera 26 and comparing the same with a reference image 36 to subject the same to image processing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating inspection apparatus for inspecting coating film formation unevenness of a tip-shaped tool such as a throw-away tip attached to a cutting edge of a tool.

  There are a great many types of throw-away tips that form the cutting edge of a tool, which have an appropriate thickness and are formed in a substantially diamond shape, a substantially square shape, a substantially regular triangle shape, or the like, and have different shapes and dimensions. In addition, the throw-away tip is formed in a unique shape to ensure the cutting function as represented by the tip breaker for promoting chip discharge, and the tip surface is surface-treated to improve durability. There are varieties that are coated. As the coating, there are those that coat titanium carbide, titanium nitride, or alumina by CVD, and those that form titanium nitride or other titanium-based films by PVD. Furthermore, many throw-away tips are manufactured by a powder sintering method, and the shape dimension may have an error of about several tens of μm.

In this case, the film formation unevenness of the coating material on the chip surface not only deteriorates the functions such as durability required for coating but also does not improve the appearance. Therefore, chips with uneven film formation must be identified and extracted as defective products, and this inspection requires delicate judgment for each of a wide variety of products, and conventional film formation unevenness is determined by visual inspection. It was.
Japanese Patent Laid-Open No. 10-202478

  In the case of extracting defective products having coating film formation unevenness by visual observation of the above conventional method, in the case of many types of products with slightly different surface shapes or patterns, there are fine film formation unevenness. It was difficult to extract defective products. As a result, defective products may be overlooked.

  Further, in the throw-away tip inspection apparatus used for the cutting edge of a tool disclosed in Patent Document 1, a laser beam is scanned to detect a shape defect of the throw-away tip's cutting edge, and the cutting edge is not damaged. Judging. However, the film formation unevenness of the coating on the throwaway tip surface cannot be extracted by this method. In general, in order to inspect by image processing, it is necessary to image the chip surface with a camera. In that case, a dome-shaped luminaire that can illuminate the chip surface without any illumination unevenness or shadow is optimal. is there. However, in this case, it is necessary to accurately set the specimen at the specified position, and the structure is complicated and the operation control is not easy.

  The present invention has been made in view of the above-mentioned problems of the prior art. By extracting the film formation unevenness of the coating applied to the surface of the tip used for the cutting edge of the tool with high accuracy, the defective product is inspected. It is an object of the present invention to provide a coating inspection apparatus capable of being easily and accurately.

  The present invention is a coating inspection apparatus for inspecting film formation unevenness of a workpiece surface coating that is a tip used for a cutting edge of a tool, and includes a pair of an illuminating apparatus that irradiates illumination light and a light that transmits the illumination light of the illuminating apparatus. A prism body composed of prisms, a half mirror located in the prism body, a support portion that supports the workpiece at a position where illumination light from the illumination device is irradiated through the half mirror, and a back side of the workpiece A reflector having a reflecting surface that is positioned and diffusely reflects the illumination light, a camera that images the workpiece illuminated by the illumination device through the prism body, and the contour and surface of the workpiece imaged by the camera A coating inspection apparatus including an image processing apparatus that extracts a captured image including an image and performs image processing in comparison with a reference image.

  The image processing apparatus is a coating inspection apparatus that separates an image acquired by the camera into each component of the three primary colors of light and performs image processing on each component image.

  In the illumination device, illumination light is applied to the prism via a diffusion surface. The irradiation surface of the prism is formed to be at least twice as wide as the workpiece width. Furthermore, it is preferable that the distance from the irradiation surface of the prism to the workpiece surface is used at a quarter or less of the width of the prism irradiation surface.

  The reflecting surface of the reflecting plate is a white color, and the image processing device adjusts the brightness and hue of each image by the reflected light from the reflecting surface when comparing the reference image and the captured image. Is what you do.

  According to the coating inspection apparatus of the present invention, film formation unevenness can be easily and accurately extracted by image processing in inspection of chip parts such as a throw-away chip. And the defective product can be detected more accurately from the extracted film formation unevenness.

  Hereinafter, an embodiment of a coating inspection apparatus according to the present invention will be described with reference to FIGS. The coating inspection apparatus 10 according to this embodiment is used for film formation unevenness inspection of a coating applied to the surface of a workpiece 12 such as a throw-away tip attached to a tool used for cutting or the like. As shown in FIG. 1, the coating inspection apparatus 10 is provided with a reflecting plate 14 fixed to a base or the like by a fixing tool (not shown), and the surface of the reflecting plate 14 is a white surface having a rough surface capable of irregular reflection. It is formed as a reflection surface 14a of the system. At the center of the reflection surface 14a, a support portion 16 is provided which has a chuck (not shown) at its end so as to be able to support a workpiece to be inspected. On the chuck (not shown) of the support portion 16, for example, the workpiece 12 formed in a substantially equilateral triangle having an appropriate thickness is placed.

  Above the workpiece 12, a prism body 22 is provided that includes a pair of triangular prisms 18 and 19 having a cross section of a right isosceles triangle and a half mirror 20 formed on one inclined surface thereof. In the prism body 22, the slopes corresponding to the oblique sides of the right triangle in the cross-sectional shape of the pair of prisms 18 and 19 face each other, and a half mirror 20 is formed on one slope of the pair of prisms 18 and 19. The prism body 22 is arranged at a position where an angle formed by an extension line of the upper surface of the work 12 fixed to the support portion 16 and the surface of the half mirror 20 is about 45 degrees.

  An illuminating device 24 formed so as to be able to irradiate diffused illumination light in the direction of the workpiece 12 is attached by a fixture (not shown) so as to face the incident surface 18a of one prism 18 of the prism body 22. The illuminating device 24 is provided at a position where the illumination light is incident on the prism body 22 through the diffusion surface and the illumination light is bent 90 ° downward on the reflection surface of the half mirror 20. The irradiation surface 18 b of the prism body 22 facing the upper surface of the work 12 is formed to have a width that is twice or more the maximum outer diameter of the work 12. In addition, the distance between the irradiation surface 18b of the prism body 22 facing the work 12 upper surface is formed to be equal to or less than one quarter of the width of the irradiation surface 18b.

  The other prism 19 of the prism body 22 has one side surface located parallel to the upper surface of the work 12 and the center located coaxially with the center of the work 12. A camera 26 such as a color CCD camera is attached above the prism 19 of the prism body 22 by a fixture (not shown) so that the workpiece 12 can be imaged through the half mirror 20.

  A signal cable 28 for transmitting captured image information is connected to the camera 26, and the other end of the signal cable 28 is connected to an image processing device 30 such as a personal computer. A display device 34 is connected to the image processing device 30 via a video cable 32. The image processing apparatus 30 includes a processing program that separates an image captured by the camera 26 into signals for each of the three primary colors of RGB light, and performs image processing to be described later for each color signal.

  Next, the processing operation of this embodiment will be described. First, a workpiece 12 such as a throw-away tip of a cutting tool is supported on a chuck (not shown) of the support unit 16. Then, the diffused illumination light from the illumination device 24 is irradiated onto the workpiece 12 from above by being reflected by the half mirror 20 through the prism 18. At this time, the irradiation light is simultaneously reflected on the reflecting surface 14a of the reflecting plate 14 below the work 12 to be irregularly reflected light, and the work 12 is also illuminated from below. Thereby, the outline of the workpiece 12 can be reliably imaged. The reflective surface 14a serves as a reference for color balance and lightness in a comparative inspection between a reference image 36 and a captured image 38, which will be described later.

  The outline and surface image of the work 12 illuminated by the illumination device 24 are transmitted through the half mirror 20 and the prism 19 from the prism 18 and imaged by the camera 26. The image of the workpiece 12 picked up by the camera 26 is taken into the image processing apparatus 30 as image data. The captured image data is inspected and determined by the image processing device 30.

  Next, the inspection method of this embodiment will be described. As illustrated in FIG. 2, the image processing apparatus 30 acquires a captured image 38 including the outline and surface image of the workpiece 12 from the camera 26 that has captured the workpiece 12 (S <b> 1). At this time, the captured image 38 of the workpiece 12 is divided into data for each of the three primary colors of RGB light. Further, in advance, the image processing apparatus 30 captures and stores a reference image 36 for each of the three primary colors in advance for comparison with the image of the workpiece 12 to be inspected.

  Subsequently, for example, as shown in FIG. 3, the brightness of the reference image 36 prepared in advance for each of the three primary colors is negative-positive inverted for collation with the image of the workpiece 12 to be inspected, and the workpiece 12 to be inspected is detected by the camera 26. The picked-up image 38 picked up by the above is separated for each of the three primary colors, and is superposed on the reference image 36 for each of the separated colors, and the difference is taken for each color and the average of each pixel is taken. Thereby, extraction of the difference component in the comparison between the reference image 36 for each color and the captured image 38 is performed (S2).

  Further, when the images are compared, a color balance is obtained with reference to the white reflection surface 14a reflected as a background common to both the reference image 36 and the captured image 38.

  Through comparison processing of the reference image 36 and the captured image 38, pixel data having a common brightness value between the reference image 36 and the captured image 38 to be inspected are canceled for each color, resulting in an intermediate density and abnormal brightness. The value remains as a different component as a different contrast. Then, as shown in FIG. 3, the difference image 40 obtained from the difference component is binarized, and the image processing apparatus 30 determines whether or not the difference component is within the specified range value (S3). In this case, if the difference component is within the specified range, the difference image 40 is a white image with almost intermediate brightness, but if the difference component is different from the reference image 36, the uneven coating portion is a black image, If this black area exceeds the specified range value, it is distinguished as a defective product.

  According to the coating inspection apparatus 10 of this embodiment, the diffuse illumination light of the illumination device 24 is uniformly irradiated onto the workpiece 12, and the surface image of the workpiece 12 can be accurately captured without a shadow. Further, the back surface of the workpiece 12 is illuminated by the reflecting surface 14a of the reflecting plate 14, the contour of the workpiece 12 can be imaged beautifully, and accurate processing can be performed in alignment in image processing and subsequent data superposition. Become. Thereby, film formation unevenness can be extracted easily and accurately by image processing. In particular, the irradiation surface 18b of the prism body 22 facing the upper surface of the work 12 is formed to have a width that is at least twice that of the upper surface of the work, and the interval between the irradiation surface 18b and the upper surface of the work 12 is a quarter of the width of the irradiation surface 18b. Formed below. Therefore, it is possible to illuminate the work 12 without forming a shadow. Further, subtle unevenness in film formation can be easily extracted by image processing, and defective products can be detected accurately. Further, since the captured image of the camera 26 uses a color image, it can cope with a change in hue due to the material of the coating, and there are few restrictions on the type of workpiece to be inspected.

  In addition, since the reflecting surface 14a of the reflecting plate 14 is used as a reference for color balance and brightness, correction can be performed easily and accurately even if the color balance or brightness of the inspection image is distorted due to deterioration of the illumination light source or disturbance light. It is. That is, since the reflection surface 14a is reflected as a background in common to both the reference image 36 and the captured image 38, the color balance and the brightness of the same white-based reflection surface 14a are used as the reference image. It is sufficient that the two images 36 and 38 are the same, and adjustment is easy.

  In addition, the coating inspection apparatus of this invention is not limited to the said embodiment, The size of the reflector of the illuminating device to illuminate, a shape, and illumination intensity are the magnitude | sizes of the workpiece | work of the test object supported by the support part. It can be set as appropriate. Further, when a large workpiece is imaged, the image data may be divided and captured and combined by an image processing apparatus to form one image data. Furthermore, the shape and material of each member can be appropriately changed.

It is a schematic side view which shows the coating inspection apparatus of one Embodiment of this invention. It is a flowchart which shows the process of the coating inspection apparatus of this embodiment. It is an extraction schematic diagram which shows the reference | standard image used for a test | inspection of the coating inspection apparatus of this embodiment, a test | inspection image, and a difference image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coating test | inspection apparatus 12 Work piece 14 Reflecting plate 14a Reflecting surface 16 Support part 18, 19 Prism 20 Half mirror 22 Prism body 24 Illuminating device 26 Camera 30 Image processing apparatus 34 Display apparatus 36 Reference image 38 Captured image

Claims (5)

  In a coating inspection apparatus that inspects film formation unevenness of a workpiece surface coating that is a tip used as a cutting edge of a tool, an illumination apparatus that irradiates illumination light, and a prism body that includes a pair of prisms that transmit illumination light from the illumination apparatus; A half mirror positioned in the prism body, a support unit that supports the workpiece at a position where illumination light from the illumination device is irradiated through the half mirror, and a back surface of the workpiece that is configured to transmit the illumination light. A reflecting plate having a reflecting surface that diffusely reflects, a camera that images the workpiece illuminated by the illumination device via the prism body, and a captured image of the workpiece imaged by the camera is extracted and compared with a reference image And an image processing apparatus for image processing.   The coating inspection apparatus according to claim 1, wherein the image processing apparatus separates an image acquired by the camera into components of three primary colors of light and performs image processing on each of the component images.   The coating inspection apparatus according to claim 1, wherein the illumination device irradiates the prism with illumination light through a diffusion surface.   The coating inspection apparatus according to claim 1, wherein an irradiation surface of the prism is formed to be at least twice as wide as a workpiece width. The reflecting surface of the reflecting plate is a white color, and the image processing device adjusts the brightness and hue of each image by reflected light from the reflecting surface when comparing the reference image and the captured image. The coating inspection apparatus according to Item 1.

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