JP2006201045A - Uneven painting measuring instrument, measuring method, and evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an uneven painting measuring instrument, measuring method, and evaluation method capable of measuring uneven painting (metal nonuniformity) of a metallic color as face information, not only in a plane but also even in a curved face of a measuring object such as a metallic-painted automobile, and capable of providing high consistency with visual evaluation. <P>SOLUTION: This painting nonuniformity measuring instrument for measuring continuously a reflected light intensity received from an angle not incident with regular reflection light to measure the painting nonuniformity, by irradiating a metallic painted face with light, includes an optical unit built in with a light emitting element and a light receiving element, and supported by three or four ball bearing rollers, a robot capable of holding the optical unit to bring all the ball bearing rollers provided in the optical unit into point contact with the painted face, and movable on the painted face, a controller for the robot, and a processor for processing the reflected light intensity measured by the optical unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is capable of measuring metallic paint unevenness (metal unevenness) as surface information not only on a flat surface but also a curved surface of a measurement object such as an automobile with metallic coating, and is highly consistent with visual evaluation. The present invention relates to a measurement device, a measurement method, and an evaluation method.

  In recent years, in order to improve the design of paint films formed on automobile outer panels, metallic coatings with paints containing glitter materials such as flake-like aluminum and mica powder have been widely adopted instead of solid color finishing. Yes.

  Optical properties of metallic coatings include brightness (whiteness), directionality (flip / flop), sparkle (glitter), coating unevenness (metal unevenness), and so on. Qualitative judgments have been made by visual inspection, and in particular, painting irregularities (metal irregularities) are often judged by skilled workers, and no effective measurement method that can be judged even by beginners has been found.

  The coating unevenness that occurs during metallic coating is due to the disorder of the arrangement of the glitter material, and depends on the coating conditions and paint conditions in the coating line, so it is required to measure the coating unevenness as part of line management. .

  Therefore, Patent Documents 1 to 3 propose methods for objectively and quantitatively measuring and evaluating the degree of coating unevenness (metal unevenness) of the metallic coating film.

JP-A-5-288690 JP-A-9-318448 Japanese Utility Model Publication No. 5-87505

  However, in the methods of Patent Document 1 and Patent Document 2, there is a problem that it is not possible to know where and how much unevenness is present from the whole painted surface as in the case of visual evaluation in order to take measurement points in a linear form. On the other hand, the apparatus of Patent Document 3 has a problem that although data as a painted surface can be obtained, accurate data cannot be obtained for an object to be measured with many curved surfaces, and its practicality is low.

  The object of the present invention is to measure the metallic coating unevenness (metal unevenness) on the entire painted surface not only on the flat surface but also on the curved surface of the object to be measured such as an automobile coated with metallic paint, which is highly consistent with the visual evaluation. An object of the present invention is to provide a coating unevenness measuring device, measuring method and evaluation method.

The present invention
1. A device that irradiates light on a metallic coating surface and continuously measures reflected light intensity received from an angle at which regular reflection light does not enter to measure coating unevenness on the coating surface,
A light-emitting element that irradiates light on the painted surface and a light-receiving element that receives reflected light from the painted surface, and an optical unit supported by three or four ball bearing rollers;
A robot capable of holding the optical unit and moving on the painted surface so that all ball bearing rollers provided in the optical unit are in contact with the painted surface;
A control device for the robot;
A coating unevenness measuring device comprising a processing device capable of processing the reflected light intensity measured by the optical unit;
2. 2. The measuring device according to claim 1, wherein the robot holding the optical unit is a two-axis robot or an arm robot having a movable joint.
3. A method of measuring coating unevenness on a painted surface using an optical unit that continuously irradiates light on a metallic painted surface and continuously measures the intensity of reflected light received from an angle at which regular reflected light is not incident.
The optical unit is in contact with and movable on the painted surface via three or four ball bearing rollers;
The coating is characterized in that the optical unit is swept into a rectangle while reciprocating in a substantially horizontal direction with respect to the coating surface at a constant speed, and the degree of coating unevenness on the entire surface to be measured is measured two-dimensionally. Measurement method of unevenness,
4.3 Evaluation method of coating unevenness obtained by evaluating coating unevenness of measurement target surface from image obtained by two-dimensional mapping of reflected light intensity data measured by method described in 4.3
An evaluation method of coating unevenness obtained by quantitatively evaluating the coating unevenness of the measurement target surface using the standard deviation of the reflected light intensity data measured by the method described in 5.3.
A coating formed by quantitatively evaluating the coating unevenness of the surface to be measured using a two-dimensional power spectrum obtained by two-dimensional Fourier transform of the reflected light intensity data measured by the method described in 6.3. Evaluation method of unevenness,
About.

  According to the present invention, an optical unit supported by three or four ball bearing rollers is applied so that all the ball bearing rollers provided in the optical unit are in point contact with a painted surface which is a measurement target surface. By reciprocating the surface at a constant speed and continuously measuring the reflected light intensity, the position of the light emitting element and light receiving element in the optical unit with respect to the normal direction of the measurement point on the painted surface is always set. Therefore, it is possible to measure with high accuracy even on the curved surface of the measurement object. Further, in the present invention, the entire surface to be measured can be evaluated because such an optical unit is swept into a rectangle while reciprocating in a substantially horizontal direction with respect to the surface to be painted at a constant speed. The agreement with the visual evaluation is high, the evaluation can be processed quantitatively, and the same evaluation result can be obtained regardless of whether or not the user is an expert.

  Therefore, the present invention is very useful for measuring coating unevenness of a shaped object having a curved surface such as an automobile coated with metallic paint.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is a schematic explanatory view illustrating an optical unit used in the present invention, and FIG. 2 is a schematic bottom view of the optical unit. FIG. 3 is a schematic explanatory diagram of the whole measuring apparatus of the present invention.

  In FIG. 1, an optical unit 3 has a light emitting element 1 for irradiating light on a painted surface as a measurement object 8 and a light receiving element 2 for receiving reflected light from the painted surface, and a light shielding cover on the outside. A part of which is provided with an opening for irradiating the measurement object 8 with light and receiving the reflected light. A ball bearing roller 4 is disposed around the opening, and the measurement object 8 is provided with a ball bearing. The roller 4 is in contact.

  In the present invention, the optical surface is used to irradiate the painted surface, which is the measurement object 8, with light, and the reflected light intensity received from an angle at which the regular reflection light does not enter is continuously measured.

  In general, when an object is irradiated with light, a part of the light is absorbed by the object according to the light absorbing ability of the object and reflected as “regular reflection light” and “diffuse reflection light”. In this specification and claims, “regularly reflected light” means the same angle as the incident light angle with respect to the normal of the contact point between the surface of the measurement object and the incident light, and from the contact point in the opposite direction to the incident light. The reflected light intensity measured by the present invention is the intensity of diffuse reflected light, and the diffuse reflected light means light scattered in all directions on the surface of the measurement object. When the light emitted from the light emitting element is parallel light, the angle of the regular reflection light is determined from the angle of the optical axis. When the light emitted from the light emitting element is diffused light having a certain extent, the regular reflected light has a diffusion angle corresponding to the diffusion angle of the irradiation light. In this case, there is a possibility that a part of the regular reflection light diffused by the light receiving element is received. However, if the intensity of the specular reflected light in the peripheral part of the specular reflected light having a diffusion angle is lower than that of the diffuse reflected light from the measurement object and does not cause a problem in measurement, the light receiving element is Receiving regular specularly reflected light is acceptable in the present invention. In the present invention, “an angle at which regular reflection light does not enter” includes such an angle.

  The light emitting element 1 and the light receiving element 2 are preferably arranged such that a part of the diffusely reflected light from the measurement object 8 is received by the light receiving element. It is desirable to set the angle within the range of 35 to 55 ° with respect to the center normal of the surface of the part. Here, the center normal of the surface means a normal passing through the center of the irradiated surface, the normal is 0 °, and the oblique angle on the light emitting element side is a positive angle. The light receiving element can be set to have an angle within a range of −45 to 25 ° with respect to the center normal of the surface of the opening.

  The opening is provided to irradiate light on the surface of the measurement object during measurement and to receive reflected light from the measurement object. The shape of the opening is not particularly limited, such as a circle or a square. It is not desirable, but it is desirable to have a symmetrical shape.

  The ball bearing roller 4 has an arbitrary shape without any limitation as long as a freely rotatable sphere can be contacted on the measurement object. As shown in FIG. Even when the optical unit 3 is swept over the measurement object having a curved surface, the light emitting element in the optical unit with respect to the normal direction of the measurement point on the measurement object surface is arranged around the opening. In addition, the light receiving element is installed so that the position of the light receiving element can always be maintained at a set angle. For that purpose, it is desirable to arrange three or four ball bearing rollers, and particularly four as shown in FIG. When five or more ball bearing rollers are installed, it becomes difficult to measure following the shape of the measurement object having a small radius of curvature. This is not desirable because it becomes unstable and the position cannot be measured accurately.

  The arrangement of the ball bearing rollers 4 is such that the vertexes of the ball bearing rollers are geometrically line symmetrical so that the light emitting element 1 and the light receiving element 2 stably maintain a fixed positional relationship during the sweep measurement of the optical unit 3. As shown in FIG. 2, the ball bearing rollers 4 can be installed at the four corners of the rectangle.

  As shown in FIG. 1, the optical unit 3 is connected to a sweep drive robot (not shown) via movable joint portions 6 and 7 and a holding arm 5. The holding arm 5 holds the optical unit so that the four ball bearing rollers 4 come into contact with the painted surface by the movable joint portions 6 and 7. With this structure, the light-emitting element 1 and the light-receiving element 2 maintain a fixed positional relationship with respect to the measurement object 8 having a curved surface, and even when the measurement object surface having a curved surface is swept, the movable joint The light emitting element 1 and the light receiving element 2 can maintain a certain distance from the measurement object by the units 6 and 7.

  In FIG. 3, the optical unit 3 is held by a two-axis robot including a single-axis robot X11 and a single-axis robot Y12 via a multi-joint holding arm 10. The multi-joint holding arm 10 includes the holding arm 5 and the movable joints 6 and 7 as shown in FIG. 1, and one end of the multi-joint holding arm 10 is fixedly connected to the single-axis robot X11, and the other end is an optical unit. 3 is fixedly connected. The single-axis robot X11 and the single-axis robot Y12 arranged orthogonally can use an actuator using a stepping motor, a servo motor, or the like, and these are controlled by each or a single robot drive control device 13.

  In the method of the present invention, by driving the biaxial robot, the optical unit 3 is swept into a rectangle while reciprocating in a substantially horizontal direction with respect to the painted surface that is the measurement object 8 at a constant speed, and the entire measurement target range is thus obtained. The degree of coating unevenness can be measured two-dimensionally.

  The electrical signal of the light receiving element 2 installed inside the optical unit 3 is appropriately converted into digital data by the A / D converter 14 and transmitted to the computer 15. Further, the robot drive control device 13 is connected to the computer 15 in order to simultaneously obtain the digital data measured by the optical unit 3 and obtained from the A / D converter 14 and the accurate position on the surface of the measurement object 8.

  The computer 15 can perform, for example, a two-dimensional mapping process, a standard deviation calculation process, and a Fourier transform calculation process from the obtained digital data. In order to output the result of the processing performed by the computer 15, a printing machine or the like can be connected as necessary.

  In the present invention, the coating unevenness of the entire measurement target surface can be evaluated from the image obtained by two-dimensional mapping obtained as described above. Moreover, the coating unevenness of the measurement target surface can be quantitatively evaluated using the standard deviation and the two-dimensional power spectrum.

  Hereinafter, the method of the present invention will be described in more detail with reference to examples.

(Create measurement object)
The object to be measured is electrodeposited and baked on a curved steel plate with a thickness of 0.8 mm, in the same way as for automobile body painting, and then coated and baked with a polyester / melamine-curing intermediate coating to form a base for metallic coating. Prepared. Next, in metallic coating, the same paint was applied under the conditions described in Table 1 below using water-based base coat paint manufactured by Kansai Paint Co., Ltd., in which aluminum flakes were blended, and measurement objects of Examples 1 to 3 were created.

(Measurement of measurement object)
Measurements in Examples 1 to 3 were performed using the same apparatus as in FIG. Driving and measurement conditions were performed under the conditions described in Table 2 below. The positional relationship between the light emitting element and the light receiving element was set to be 45 ° incident / 35 ° light received.

(Evaluation and analysis of measurement data)
4, 5 and 6 show processed images obtained by two-dimensionally mapping 78 × 25 points of data obtained by measurement for each example with 8 gradations. On the two-dimensional mapping image, the smaller the difference in shading, the less the coating unevenness (metallic unevenness), and the superiority or inferiority of the coating unevenness (metallic unevenness) of the measurement evaluation object regardless of the level of skill of the visual evaluation of the engineer. Can be recognized and determined. Specifically, Example 1 (FIG. 4) has little coating unevenness, Example 2 (FIG. 5) is excellent with no unevenness, and Example 3 (FIG. 6) shows remarkable coating unevenness. . In this embodiment, the two-dimensional mapping is created using Microsoft spreadsheet software “Excel”. However, any software that can display two-dimensional numerical data can be selected and used as appropriate. it can.

  Furthermore, quantitative evaluation of the data obtained by measurement can be derived by analysis by Fourier transform. The processed images of the two-dimensional power spectrum obtained by performing the two-dimensional Fourier transform for each example are shown in FIGS. The two-dimensional Fourier transform is performed using 50 × 50 square data among the measurement data. In particular, in the low frequency data (1 to 10 Hz) in which a remarkable difference is recognized, the higher the value of the spectrum data, the lighter the brightness. Is shown to be smaller. As shown in Table 3, the maximum value of the two-dimensional power spectrum data shows a negative correlation with the qualitative sensory evaluation obtained from the two-dimensional mapping of the measurement data. It can be seen that the degree can be quantitatively evaluated.

It is a schematic explanatory drawing explaining the optical unit used by this invention. It is a bottom face schematic diagram of an optical unit. It is a schematic explanatory drawing of the whole measuring device of this invention. FIG. 6 is an eight-gradation two-dimensional mapping diagram obtained by measurement in Example 1. FIG. 6 is an eight-gradation two-dimensional mapping diagram obtained by measurement in Example 2. FIG. 6 is an eight gradation two-dimensional mapping diagram obtained by measurement in Example 3. 2 is a two-dimensional Fourier transform power spectrum of Example 1. FIG. 2 is a two-dimensional Fourier transform power spectrum of Example 2. FIG. 3 is a two-dimensional Fourier transform power spectrum of Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Light receiving element 3 Optical unit 4 Ball bearing roller 5 Holding arm 6, 7 Movable joint part 8 Measurement object 10 Articulated holding arm 11 Single axis robot X
12 Single-axis robot Y
13 Robot Drive Control Device 14 A / D Converter 15 Computer

Claims (6)

A device that irradiates light on a metallic coating surface and continuously measures reflected light intensity received from an angle at which regular reflection light does not enter to measure coating unevenness on the coating surface,
A light-emitting element that irradiates light on the painted surface and a light-receiving element that receives reflected light from the painted surface, and an optical unit supported by three or four ball bearing rollers;
A robot capable of holding the optical unit and moving on the painted surface so that all ball bearing rollers provided in the optical unit are in contact with the painted surface;
A control device for the robot;
A coating unevenness measuring device comprising: a processing device capable of processing the reflected light intensity measured by the optical unit. The measuring apparatus according to claim 1, wherein the robot holding the optical unit is a biaxial robot or an arm robot having a movable joint. A method of measuring coating unevenness on a painted surface using an optical unit that continuously irradiates light on a metallic painted surface and continuously measures the intensity of reflected light received from an angle at which regular reflected light is not incident.
The optical unit is in contact with and movable on the painted surface via three or four ball bearing rollers;
The coating is characterized in that the optical unit is swept into a rectangle while reciprocating in a substantially horizontal direction with respect to the coating surface at a constant speed, and the degree of coating unevenness on the entire surface to be measured is measured two-dimensionally. Measurement method of unevenness. A method for evaluating coating unevenness by evaluating coating unevenness on a measurement target surface from an image formed by two-dimensionally mapping the reflected light intensity data measured by the method according to claim 3 over the entire measurement target surface. A method for evaluating coating unevenness obtained by quantitatively evaluating the coating unevenness of the measurement target surface using the standard deviation of the reflected light intensity data measured by the method according to claim 3. Coating unevenness obtained by quantitatively evaluating the coating unevenness of the measurement target surface using a two-dimensional power spectrum obtained by performing two-dimensional Fourier transform on the reflected light intensity data measured by the method according to claim 3. Evaluation method.

Images