JP4063757B2 - Quality evaluation system for zinc phosphate coating and process monitoring system for zinc phosphate coating treatment - Google Patents

Description

  The present invention relates to a chemical film quality evaluation / process monitoring method and a chemical film quality evaluation for evaluating the film quality of a crystalline conversion film formed on a metal surface such as a metal part, or for monitoring the variation of the treatment process. / With regard to the process monitoring system, in particular, it is not possible to perform indirect quality evaluation using substitutes (test pieces, etc.) or qualitative sensory evaluation by visual appearance, but evaluation / process monitoring using actual products is possible. The present invention relates to an objective and quantitative film quality evaluation / process monitoring that can be performed relatively inexpensively.

  As one of the films formed on the metal surface, a chemical conversion film is widely used. In order to improve the durability of the coating, the chemical conversion film is formed on the surface of a metal such as a road sign for the purpose of improving the adhesion between the coating and the metal. Formed on the surface of a metal part such as a gear. In the chemical conversion film treatment step, the surface of the metal part is first subjected to pretreatment such as degreasing, water washing and surface adjustment, and then the chemical conversion film treatment is performed to form a chemical conversion film.

  Since the formation state of the chemical film greatly affects the adhesion (or peelability), corrosion resistance, rust resistance and lubricant performance of the coating, a film quality evaluation is performed to evaluate the formation state of the chemical film after the formation of the chemical film. It has been broken. As the film quality evaluation of the chemical conversion film, evaluation by evaluation characteristics using color, film mass, film composition, contained elements and the like as evaluation characteristics is performed. When color is an evaluation characteristic, quality is evaluated by visually observing the color unevenness of the film of the treated test piece (test piece) under diffuse daylight, and when the film mass is the evaluation characteristic. , Evaluate the quality by calculating the value obtained by dividing the film of the treated test piece treated with the product with the film remover and dividing the mass difference before and after by the surface area of the treated test piece, In the case of the evaluation characteristics, the quality is evaluated by measuring the composition of the film and the contained elements using an X-ray analyzer and an X-ray measuring device, respectively.

  Moreover, since the normality / abnormality of the chemical conversion film treatment process affects the quality of the chemical conversion film, the treatment process is monitored. As a method for monitoring a processing step, there is a monitoring method for monitoring the above-described fluctuations in evaluation characteristics in time series. For example, a method for creating and monitoring a control chart such as an X (bar) -R control chart is widely used. ing. The control chart includes a center line (CL), an upper control limit line (UCL) and a lower control limit line (LCL) rationally defined above and below the center line (CL), and values of evaluation characteristics. Is plotted on the control chart, and the fluctuation of the processing process is monitored by monitoring whether it is within the range of the upper control limit line (UCL) and the lower control limit line (LCL). For example, if the time-series transition of the evaluation characteristic value is within a predetermined control limit, the processing process is normal, if it is outside the control limit, it is evaluated that an abnormality has occurred, or the evaluation characteristic value trend is analyzed, For example, when the value of the evaluation characteristic continuously increases or decreases, the occurrence of abnormality is predicted and the processing process is monitored.

  These film quality evaluations and process monitoring are often performed using steel plate-shaped processed test pieces (test pieces) defined by JIS. In particular, the appearance and color of the evaluation characteristics are nondestructive, so it is possible to evaluate using actual products. However, if the film mass, film composition, and contained elements are used as evaluation characteristics, it is destructive. Since it is evaluation, it is required to evaluate using a treated test piece. However, since the treatment test piece prescribed by JIS or the like is used for the film evaluation, the material, size, finish state of the metal surface, and the like are different from actual products, so that the generation state of the chemical conversion film is also greatly different. For this reason, even if the evaluation result is good in the processed test piece, the actually produced product may be defective, and the evaluation result and the monitoring result are not reliable.

  When color is used as an evaluation characteristic, it is possible to use the actual product, but human sensory evaluations such as observing subtle color differences and unevenness by visual observation of the formed film under diffuse daylight Therefore, there is a problem that it is easily influenced by the subjectivity of the inspector and quantitative and objective evaluation and monitoring cannot be performed.

  Furthermore, in the case where the coating mass, coating composition, and contained elements are used as evaluation characteristics, peeling treatment, diffraction / measurement by X-rays, and the like are necessary, and a period of several hours is required. For this reason, if production is performed without waiting for the evaluation result with an emphasis on production efficiency, if the evaluation result is bad, the product produced during the evaluation period will be defective and the yield will be reduced, with an emphasis on yield. When production was started after confirming the results, a time lag of several hours was generated, resulting in a problem that production efficiency was lowered. In addition, since real-time performance is required in process monitoring, an evaluation method using these evaluation characteristics that generate a time lag of several hours is unsuitable for process monitoring.

  Furthermore, when film composition and contained elements are used as evaluation characteristics, objective and quantitative evaluation can be performed, but a very expensive X-ray diffraction apparatus and fluorescent X-ray apparatus are required, so that the burden of initial investment is large. Furthermore, there has been a problem that advanced techniques are required for measurement and determination. For this reason, it has only been introduced at the level of major laboratories and is not used for evaluation of actual production.

  Therefore, the present invention can evaluate the coating quality in real time and monitor the processing process using an actual product without using a processing test piece, and further, objective and quantitative coating quality. It is an object of the present invention to provide a chemical conversion film quality evaluation / process monitoring system and a chemical conversion film quality evaluation / process monitoring method using evaluation characteristics that allow evaluation and process monitoring to be performed relatively inexpensively and easily.

  The inventors have conducted various studies and experiments in order to discover evaluation characteristics that can achieve the above-mentioned objectives for evaluation of the film quality of the crystalline chemical conversion film and monitoring of the treatment process. As a result, in the case of a crystalline conversion coating, the appearance (size, shape, etc.) of the crystal grains of the conversion coating varies depending on the normality of the treatment process, and the appearance (size, shape, etc.) of the crystal grains is good or poor in coating quality (painting) It has been clarified that it greatly affects the adhesion, corrosion resistance and quality of the lubricant function. The crystal grains of the chemical conversion film differ in appearance in terms of size, shape, etc. depending on the film formation conditions, such as the type of metal on which the chemical conversion film and the chemical conversion film are formed, and the finish state of the metal surface. It was found that there was a grain appearance. For example, the shape of crystal grains differs depending on quality of a zinc phosphate-based film, and the size of crystal grains differs depending on quality of a manganese phosphate-based film. In addition, when the characteristics of the appearance of crystal grains are digitized and used as characteristic values, those whose characteristic value distribution does not approximate the normal distribution are unsuitable for evaluation characteristics, and the characteristic value distribution approximates the normal distribution. What to do is preferable as an evaluation characteristic.

Further, among the crystalline chemical conversion films, detailed studies were conducted on zinc phosphate-based films widely used as iron and zinc films. Zinc phosphate-based coatings form dense zinc phosphate insoluble crystals by immersing metal parts with zinc phosphate-based treatment liquids (including zinc phosphate treatment liquids and those with accelerators added). To do. Zinc phosphate contained in the zinc phosphate treatment liquid is a water-soluble compound, but the zinc phosphate film formed after the treatment becomes insoluble white crystals whose composition is modified. The coating composition of zinc phosphate is Zn ₂ (P 0 ₄ ) ₂ .4H ₂ O and Zn ₃ Fe (P 0 ₄ ) ₂ .4H ₂ O.

  Fig.1 (a) is a figure which shows an example of the zinc phosphate type | system | group chemical conversion film with favorable film quality formed in the metal surface, (b) is an example of the zinc phosphate type chemical conversion film with inferior film quality. FIG. 2 is an explanatory diagram for explaining an example of the evaluation characteristics of the chemical conversion film. FIG. 3 is a diagram showing the results of research on zinc phosphate-based films. The inventors of the present invention have found that when the shape of the crystal grains is a scale-like fine piece, an abnormality has occurred in the film processing process and the film quality is poor, and when the crystal grain shape is substantially elliptical (foliate crystal), the film processing is performed. It was found that the above process was normal and the film quality was good.

  Furthermore, as illustrated in FIG. 2, when the zinc phosphate coating film is replaced with the same elliptical shape in terms of area, primary moment, and secondary moment, the crystal grain shape of the chemical conversion coating is as shown in FIG. 3. In addition, it was confirmed that the quality was good when the average value X (bar) was about 2.3 or more. From this result, when the ratio (ellipse axis ratio) x of the length of the major axis Ld to the length of the minor axis Sd of the elliptical shape is within a predetermined range, the quality tends to be good, and a plurality of crystal grains It was clarified that the quality can be judged quantitatively by judging by the average value X (bar) of the ratio x. FIG. 4 shows the detection of crystal grains in a plurality of regions for a product H, and calculates the average value X (bar) of the ratio (elliptic axis ratio) x of the crystal grains for each region. It is an example of the histogram showing the frequency of occurrence of. It can be seen that the histogram approximates a normal distribution and is preferable as an evaluation characteristic. Furthermore, from the result of the adhesion test, it was found that the average value X (bar) of the product H is preferably in the range of about 2.3 or more. Here, specifically, the shape of the crystal grain means a shape surrounded by the outline of the crystal grain in an image obtained when the crystal grain is imaged in a direction perpendicular to the metal surface. Means the size of the area of the shape surrounded by the contour. (See FIG. 2).

  In addition, when a control chart was created using various evaluation characteristics and the evaluation characteristics preferable for the process monitoring (normal or abnormal) of the coating treatment were examined, the ratio x was set as the evaluation characteristics for the zinc phosphate-based film, and the ratio If the average value X (bar) of x is within the predetermined range, or the difference R between the maximum value X (max) and the minimum value X (min) of the average value X (bar) of the ratio x is within the predetermined range It was clarified that the coating process was normal (see X (bar) -R control chart in FIG. 10).

  From the above, the inventors can evaluate the film quality and monitor the treatment process using the information obtained from the appearance of the crystal grains as the evaluation characteristics for the crystalline chemical film, and can be obtained from the appearance. Which information is used depends on the type of film, the type of metal, the formation conditions such as the finish state of the metal surface, etc., but especially for zinc phosphate-based films, the shape of the crystal grains of the chemical conversion film It was derived that it is desirable to replace the area, the first moment, and the second moment with the same elliptical shape, and to use the ratio x of the major axis length to the minor axis length as the evaluation characteristic. And from these results, the chemical film quality evaluation / process monitoring method and chemical film quality evaluation / process monitoring system of the present invention were completed.

  The present invention relates to a crystalline chemical film formed by treating a metal surface with a treatment agent, and evaluates the quality of the chemical film from the evaluation characteristics or monitors the chemical film treatment process. In the process monitoring method, the appearance of the crystal grain of the chemical conversion film is used as an evaluation characteristic.

  From the above studies and experiments, it has been found that it is preferable to use the crystal appearance of the chemical conversion film (the shape and size of the crystal grains) as the evaluation characteristics in the quality evaluation of the crystalline chemical conversion film and the monitoring of the treatment process. According to the present invention, it is possible to evaluate the quality of the chemical conversion film and monitor the processing step by using the appearance of the crystal grains of the chemical conversion film as an evaluation characteristic. Since it is a non-destructive evaluation based on appearance observation, film evaluation or process monitoring can be performed using an actual product without using a test piece. Since the size and shape can be handled as numerical values, objective and quantitative quality evaluation or process monitoring is possible. Compared with the case where the coating composition is used as the evaluation characteristic, the processing time is short, so the coating evaluation and process monitoring can be performed in real time, and expensive equipment such as an X-ray diffractometer is unnecessary, so the initial investment in equipment is low. is there.

In the present invention, as the evaluation characteristic information, information whose characteristic value approximates a normal distribution, that is, the crystal grain shape of the chemical conversion film is replaced with the same elliptical shape with respect to area, primary moment and secondary moment, and the elliptical shape is obtained. The ratio x between the minor axis length Sd and the major axis length Ld is used as an evaluation characteristic, and an average value X of the ratio x is used.

  From the above studies and experiments, it is preferable that the information used as the evaluation characteristics take characteristic values that approximate a normal distribution. According to this invention, since the information whose characteristic value approximates the normal distribution is used as the evaluation characteristic, the quality evaluation and the process monitoring can be performed using the preferable evaluation characteristic.

  The present invention is characterized in that the shape or size of the crystal grain of the chemical conversion film is an evaluation characteristic.

  According to the present invention, since the film quality is evaluated based on the shape and size of crystal grains that can be handled as numerical values, objective and quantitative quality evaluation and process monitoring can be performed. For acicular crystals found in zinc phosphate coatings, the shape of the crystal grains is the evaluation characteristic, and for granular crystals found in manganese phosphate coatings, the size (area) of the crystal grains is evaluated. It is preferable to have characteristics.

In the present invention, the crystal grain shape of the chemical conversion film is replaced with the same elliptical shape in terms of area, primary moment and secondary moment, and the ratio x between the short axis length Sd and the long axis length Ld of the elliptical shape is determined. Evaluation characteristics are characterized in that the quality of the chemical conversion film is evaluated as being good when the average value X of the ratio x is equal to or greater than a predetermined value , and otherwise being poor.

From the above research results, it has been clarified that the quality of the chemical conversion film is good particularly when the average value X (bar) of the ratio x is not less than a predetermined value for the zinc phosphate-based film. According to this, since the quality is evaluated from the average value X (bar) of the crystal grains, an objective and quantitative quality evaluation is possible. The predetermined value or higher that results in good quality is appropriately determined by experiments or the like according to the type of chemical conversion coating or metal product material, surface finishing conditions, etc. In the example of product H, it may be about 2.3 or more. preferable.

The present invention replaces the shape of each crystal grain with the same elliptical shape with respect to area, first moment, and second moment for each piece of image data of the plurality of pieces of image data, A ratio x of the length Ld of the major axis is calculated, an average value X (bar) a of the ratio x is calculated for each image data, and an average value X (bar) a of the calculated plurality of image data is calculated. Monitor the processing step from the average value X (bar) b and the difference R between the maximum value X (max) and the minimum value X (min) of the calculated average value X (bar) a of the plurality of image data. It is characterized by.

From the above research results, the average value X (bar) b and the maximum value X (max) and the minimum value X (min) of the average value X (bar) a of the ratio x, especially for the zinc phosphate-based film, are shown. When the difference R is within the predetermined range, it has been clarified that the chemical conversion film treatment process is normal. According to this invention, since the treatment process of the chemical conversion film is monitored from the average value X (bar) b and the difference R of the crystal grains, objective and quantitative process monitoring is possible.

  The present invention relates to a crystalline conversion coating formed by treating a metal surface with a treatment agent, from the evaluation characteristic information that serves as an index for the quality evaluation of the conversion coating or the process monitoring of the conversion coating treatment. This is a chemical film quality evaluation / process monitoring system that evaluates the chemical conversion film or monitors the chemical film treatment process, and extracts the crystal grains of the chemical conversion film contained in the image data and the crystal grain extraction means. Evaluation characteristic information acquisition means for acquiring evaluation characteristic information from the appearance of the crystal grains formed.

  The chemical conversion film quality evaluation / process monitoring system of the present invention is realized by a computer such as a personal computer, and image data to be used is, for example, imaging a crystalline chemical conversion film formed on a metal surface with an imaging means such as a microscope. This is the image data obtained. According to the quality evaluation / process monitoring system of the chemical conversion film of the present invention, the crystal grain extraction means extracts the crystal of the chemical conversion film contained in the image data, and the evaluation characteristic information acquisition means extracts the crystal extracted by the crystal grain extraction means. Evaluation characteristic information that is a judgment index for quality evaluation and process monitoring of the chemical conversion film is acquired from the appearance of the grains. From the above studies and experiments, it has been found that it is possible to evaluate the quality of the chemical conversion film or to monitor the treatment process according to the appearance of the crystal grains of the chemical conversion film. The quality of the chemical conversion film can be evaluated or the process can be monitored. Since it is a non-destructive evaluation, evaluation or monitoring can be performed with a product such as an actual metal part without using a processed test piece. Compared with film composition evaluation and the like, the evaluation time is short, and an expensive apparatus such as an X-ray diffraction apparatus is not required, so the initial investment for the evaluation equipment is low.

In the present invention, as the evaluation characteristic information, information whose characteristic value approximates a normal distribution, that is, the crystal grain shape of the chemical conversion film is replaced with the same elliptical shape with respect to area, primary moment and secondary moment, and the elliptical shape is obtained. The ratio x between the minor axis length Sd and the major axis length Ld is used as an evaluation characteristic, and an average value X of the ratio x is used.

  According to the present invention, since the information approximated to the normal distribution is used as the evaluation characteristic information, the quality evaluation and the process monitoring are performed using the preferable evaluation characteristic information as the quality evaluation index or the chemical film coating process monitoring index. be able to.

  The quality evaluation / process monitoring system for a chemical conversion film according to the present invention is characterized in that the evaluation characteristic information is a shape or size of a crystal grain.

  According to the present invention, the crystal grain extraction means extracts the crystal grains contained in the image data of the chemical conversion film, and the evaluation characteristic information acquisition means calculates or measures the shape or size of the chemical grains of the chemical conversion film as evaluation characteristic information. Get by. According to the present invention, since the shape and size (including area) of crystal grains that can be expressed as numerical values are used as evaluation characteristic information, objective and quantitative quality evaluation and process monitoring can be performed.

  In the present invention, the evaluation characteristic information is obtained by replacing the crystal grain shape of the chemical conversion film with the same elliptical shape with respect to the area, the primary moment, and the secondary moment. The ratio is the ratio x of the shaft length Ld.

  From the results of the above studies and experiments, it was found that the quality of the chemical conversion coating and the monitoring of the treatment process can be monitored by using the ratio x as an evaluation characteristic, particularly for the zinc phosphate coating. According to the present invention, the crystal grain extraction means extracts the crystal grains contained in the image data of the chemical conversion film, and the evaluation characteristic information acquisition means extracts the crystal grain shape of the chemical conversion film as the area, the first moment, and the secondary The moment is replaced with the same elliptical shape, and the ratio x of the major axis length to the minor axis length of the elliptical shape is calculated. The inspector can perform quality evaluation and process monitoring using the calculated ratio x as evaluation characteristic information.

The present invention, when the average value X of the ratio x of said calculated for each crystal grain (bar) is not less than the predetermined value notifies quality Ru excellent der, poor quality if it is otherwise It is characterized by notifying.

According to the present invention, it is notified that the quality is good when the average value X (bar) of the ratio x is equal to or greater than the predetermined value , and the quality is bad otherwise . The predetermined value is a value that is statistically derived in advance by a quality comparison experiment or the like. The inspector is saved the trouble of judging the quality.

The present invention replaces the shape of each crystal grain with the same elliptical shape with respect to area, first moment, and second moment for each piece of image data of the plurality of pieces of image data, A ratio x of the length Ld of the major axis is calculated , an average value X (bar) a of the ratio x is calculated for each image data, and an average value X (bar) a of the calculated plurality of image data is calculated. The average value X (bar) b and the difference R between the maximum value X (max) and the minimum value X (min) of the calculated average value X (bar) a of the plurality of image data are determined as the average value X The upper control limit value X (bar) UCL and lower control limit value X (bar) LCL of (bar) b and the upper control limit value RUCL and lower control limit value RLCL of the difference R are indicated as X (bar) −R It is characterized by being displayed in real time on a control chart.

According to the present invention, an inspector can analyze a control chart and detect a process abnormality or the like from the control chart, for example, by predicting a process process abnormality when the graph continuously rises or falls. It becomes.

  According to the present invention, the crystal grain extraction means may be configured such that, among objects included in the image data, the size of the object is included in a predetermined range, or the shape of the object is the same for the area, the first moment, and the second moment. The object is replaced with an elliptical shape, and an object in which the ratio x of the minor axis length Sd and the major axis length Ld of the elliptical shape is included in a predetermined range is extracted as a crystal grain of the chemical conversion film.

  Since the image data may include streak-like patterns or the like as objects in addition to the crystal grains of the chemical conversion film, when all objects are extracted as crystal grains, other than crystal grains are erroneously extracted as crystal grains. In addition, a plurality of overlapping crystal grains may be erroneously extracted as one crystal grain (see FIG. 5). The inventors have found that a single crystal grain is different in size (including area) compared to an object other than a crystal grain or a plurality of overlapping crystal grains, or the shape of an object is defined as an area, a primary moment, and a secondary moment. The ratio of the length x of the major axis Ld to the minor axis length Sd of the elliptical shape tends to be different when the same elliptical shape is replaced with the same elliptical shape. We found that it can be extracted with high accuracy. According to the present invention, in the crystal grain extraction means, by utilizing the size (including the area) of the object and the ratio x between the short axis length Sd and the long axis length Ld, The possibility that an object and a plurality of overlapping crystal grains are erroneously extracted as one crystal grain can be reduced.

  The image data used in the quality evaluation / process monitoring system of the chemical film of the present invention is an image obtained by imaging a part of the chemical film surface of the product to be inspected. It is preferable to use a plurality of captured image data. The chemical conversion film varies in appearance of crystal grains depending on the site. For example, in the formation of the chemical conversion film by the dipping method, the upper side may have a good film quality, but the lower side may have a poor film quality. For this reason, if only one part of the chemical conversion film surface is evaluated, there is a possibility that an erroneous judgment may occur in the film quality of the entire product. By evaluating the film quality using a plurality of image data obtained by imaging a plurality of regions, it is possible to prevent an erroneous determination due to variation due to the part.

  As is apparent from the above description, according to the film evaluation method or the chemical film quality evaluation / process monitoring system of the present invention, quality evaluation and process monitoring are performed using information obtained from the appearance of the chemical film crystal as evaluation characteristics. Therefore, evaluation and monitoring can be performed without destroying the inspection target. Therefore, it is possible to evaluate / monitor a film formed on an actual product (such as a metal part) without using a processed test piece, and the reliability is improved. If information that can be handled as numerical values is an evaluation characteristic, it is possible to make an objective and quantitative evaluation. If the quality evaluation / process monitoring method and quality evaluation / process monitoring system of the chemical conversion film of the present invention are incorporated in a production line, evaluation / monitoring can be performed in real time without requiring several hours for the evaluation and monitoring period as in the past. It can be performed, and there is no problem that the production efficiency is lowered due to the yield reduction or the production interruption during the evaluation period. Furthermore, since an expensive apparatus such as an X-ray diffraction apparatus is not required, the film quality can be evaluated relatively inexpensively.

  Hereinafter, a quality evaluation / process monitoring system for a chemical conversion film according to the present invention will be described in detail with reference to the drawings.

  FIG. 6 is a conceptual diagram illustrating the chemical film quality evaluation / process monitoring system Sys according to the first embodiment of this invention. The chemical film quality evaluation / process monitoring system Sys is a personal computer having a central processing unit (CPU), storage means such as a memory and a hard disk, and display means such as a liquid crystal display. The quality evaluation / process monitoring program Sys is stored in the chemical film quality evaluation / process monitoring system Sys, and this quality evaluation / process monitoring program includes crystal grain extraction means m1, evaluation characteristic information acquisition means m2, and quality. The computer is functioning as a chemical film quality evaluation / process monitoring system Sys comprising a notification means m3 and a process monitoring means m4.

  FIG. 1 is a view showing an example of image data D used in the chemical film quality evaluation / process monitoring system Sys, (a) is an image data D showing an example of a good quality film, and (b). Is image data D showing an example of a film with poor quality. Image data D is image data obtained by imaging a zinc phosphate-based film formed on a metal surface of a metal product with an imaging means such as a microscope. The image data D is used in a state stored in advance in the chemical film quality evaluation / process monitoring system Sys or in a state sequentially read from a storage medium such as another computer or a compact disk.

  FIG. 7 is an example of the display screen P1 of the chemical film quality evaluation / process monitoring system Sys. The display screen P1 is extracted by an image designating unit P1a that allows the inspector to designate the image data D, an image data display unit P1b that displays the image data D, and an extraction condition input unit P1c that inputs the crystal grain extraction conditions. A measurement result display unit P1d for displaying the measurement result of the crystal grains, a determination condition input unit P1e for inputting the determination condition for quality quality, and an evaluation result display unit P1f for displaying the quality of the film quality as the evaluation result Prepare.

  The crystal grain extraction unit m1 is a unit that extracts crystal grains of the chemical conversion film included in the designated image data D. Specifically, crystal grains are extracted from the image data D designated by the image designation unit P1a on the display screen P1 under the extraction conditions designated by the extraction condition input unit P1c. Here, “the major axis with respect to the short axis length Sd of the elliptical shape when the object color, size (including area), and the shape of the object are replaced with the same elliptical shape with respect to the area, the first moment, and the second moment. The range of the ratio L of the length Ld (corresponding to the range from the maximum value to the minimum value of the ellipse ratio in FIG. 8) ”is used as an extraction condition, and an object is extracted as a crystal grain under the input extraction condition. Only one of color, size, or ratio x may be used as the extraction condition. This prevents an error in extracting an object other than crystal grains, such as impurities and stripe patterns on the surface of the film, and a plurality of overlapping crystal grains as one crystal grain. The extraction conditions may be stored in advance in the chemical film quality evaluation / process monitoring system Sys without being specified by the inspector. However, since the extraction conditions vary depending on the type of film and the forming environment, appropriate extraction conditions can be sequentially determined for each inspection object by enabling specification on the display screen as in the present embodiment.

  The designated image data D is displayed on the image data display part P1b, and after the crystal grain is extracted by the crystal grain extracting means m1, the outline of the crystal grain is displayed with a red line. (See FIG. 8).

The evaluation characteristic information acquisition means m2 obtains evaluation characteristic information that is a judgment index for film quality evaluation (good or bad) or film processing process monitoring (normal / abnormal) from the crystal grains of the chemical conversion film extracted by the crystal grain extraction means m1. Has a function to acquire. The evaluation characteristic information acquired by the evaluation characteristic information acquisition unit m2 is preferably information that approximates a normal distribution when the quality is good among information obtained from the appearance of the crystal grains of the chemical conversion film. In this embodiment, as shown in FIG. 2, the evaluation characteristic information is obtained when the shape of the crystal grain of the chemical conversion film is replaced with the same elliptical shape with respect to the area, the first moment, and the second moment. A ratio x of the length Ld of the major axis to the length Sd of the minor axis is assumed. The average value of the ratio x is preferable as an evaluation characteristic because it approximates a normal distribution (see FIG. 4). The ratio x is calculated by Equation 1.

  The evaluation characteristic information may be any index that can determine whether the film quality of the chemical conversion film is normal or abnormal, among the information acquired from the appearance of the crystal of the image data D from which the crystal is extracted, It is not limited to the average value of the ratio x. In the present embodiment, the average value of the ratio x suitable for the film quality evaluation of the zinc phosphate-based film is used as the characteristic information, but the determination index is based on the formation conditions such as the film type, the metal type, and the finish state of the metal surface. Therefore, information corresponding to the type, formation condition, etc. may be acquired as the characteristic information, and the crystal size (area), the crystal distribution state, etc. may be used as the characteristic information. For example, if the target metal is iron or zinc and the treatment agent such as zinc phosphate, manganese phosphate, calcium phosphate is changed in relation to each target metal, a crystalline chemical conversion film is generated. Evaluation characteristic information corresponding to these types and formation conditions may be used. As the evaluation characteristic information, it is preferable to use information in which the characteristic value obtained by quantifying the characteristic approximates a normal distribution.

The quality notifying unit m3 notifies that the coating quality is good when the evaluation characteristic information acquired by the evaluation characteristic information acquiring unit m2 satisfies a predetermined condition, and indicates that the coating quality is poor when the evaluation characteristic information is not satisfied. Specifically, the average value X (bar) of the ratio x is calculated. If it is within a predetermined range, it is notified that the quality is good, and if it is outside the predetermined range, it is notified that the quality is poor. The average value X (bar) is calculated by Equation 2 or Equation 3, where n is the number of crystal grains extracted from the image data D. In the present embodiment, the average value X (bar) is the average value X (bar) a for each image data D according to Equation 2, but may be the average value X (bar) b for a plurality of image data D. For example, with respect to N pieces of image data obtained by imaging a plurality of (N) areas for one product, an average value X (bar) a is calculated for each image data D using Equation 2, and the average value of Xa X (bar) b may be calculated by Equation 3 and the average value X (bar) b for each product may be used.

  The ratio x and average value X (bar) are stored in the storage means (hard disk or the like) of the chemical conversion film quality evaluation / process monitoring system Sys or other storage medium, and the average value X (bar) or average value X (bar) Is displayed on the analysis result display portion P1g of the display screen P1 (FIG. 8). In the present embodiment, the average value X (bar) is changed from the maximum value X (max) to the minimum value X (min) based on the determination condition input to the determination condition input unit P1e of the display screen P1 by the inspector. If it is within the range, "OK" is displayed on the evaluation result display part P1f to notify that the film quality is good, and if it is outside the range from the maximum value X (max) to the minimum value X (min) “NG” is displayed on the result display portion P1f to notify that the film quality is poor.

  The quality notification means m3 and the film quality display part P1f do not need to be provided, and the quality of the film is judged by the inspector visually checking the average value X (bar) displayed on the analysis result display part P1g of the display screen P1. You may judge. However, it is preferable to provide the quality notification means m3 from the viewpoint of work efficiency and prevention of human erroneous judgment.

  Moreover, the quality evaluation / process monitoring system Sys of the chemical conversion film has a function of continuously evaluating a plurality of image data D. For example, from the viewpoint of improving reliability, when evaluating a plurality of areas for one inspection object, the plurality of areas are imaged for one inspection object (product) (for example, 8 for a product composed of eight surfaces). The plurality of image data D are evaluated respectively. The quality evaluation / process monitoring system Sys of the chemical conversion film displays a “continue” button when the evaluation of the image data D in one region is completed (see FIG. 8), and when the “continue” button is clicked, the image data is displayed. The quality of the image data D in another area stored in association with D is evaluated by the above-described series of processing. Thereby, the trouble of performing the operation of designating each of the plurality of image data D is saved.

  The chemical film quality evaluation / process monitoring system Sys functions as a process monitoring system in response to a click on a process monitoring button (not shown), and displays a data input display screen P2 (FIG. 9). The data input display screen P2 includes a management value input unit P2a that prompts input of each management value (CL, UCL, LCL), and a data input unit P2b that prompts input of an average value X (bar). The management value input unit P2a can input management values (CL, UCL, LCU) for each X (bar) management chart and R management chart. The values of each UCL, LCL, and CL input to the management value input unit P2a are values that are statistically obtained in advance from the average value X (bar) obtained by experiments and the time series data of the difference R. When a file name is designated, the data input part P2b displays a plurality of (N) average values X (bar) stored in association with the file name inserted into the respective columns X1, XN. It has come to be. The N average values X (bar) stored in association with each other are information groups that make sense as process management, such as information groups classified by product or time. In the present embodiment, for a plurality (N) of image data D obtained by imaging a plurality of (N) regions of one product, the average value of the ratio x of crystal grains calculated for each image data D X1,..., XN are stored as information groups in association with each other so that they can be specified by one file name.

  Here, the control chart is a table format or a graph format chart used for statistically managing the process by judging variations due to accidental causes and variations due to abnormal causes in the process (see FIG. 10). It is widely used not only in the field of invention but also in various fields. The control chart of the present embodiment has one central value (CL), and an upper control limit value (UCL) and a lower control limit value (LCL) reasonably determined above and below it. There are various control charts such as average and range control charts (X (bar) -R control charts), individual measurement value control charts, defect rate control charts, and defect count control charts per unit. There are types. Any control chart may be generated by the quality evaluation / process monitoring system Sys of the chemical conversion film, and a control chart of a type designated by the inspector can be selectively generated. Hereinafter, an X (bar) -R control chart will be described as an example. The X (bar) -R control chart gives a lot of information about the state of the process, and is a typical control chart that is generally widely used.

  The process monitoring unit m4 notifies the normality / abnormality of the processing process from the average value X (bar) associated with the designated data and the management values (CL, UCL, LCL) input to the management value input unit P2a. To do. This embodiment uses a ratio x as evaluation characteristic information in a conventional process monitoring method using a control chart. Note that the difference R is described as a standard deviation in FIGS. 7 and 8 and is displayed on the display screen P1.

  Specifically, the process monitoring unit m4 uses the ratio x calculated by the evaluation characteristic information acquisition unit m2, and the average value X (bar) of the ratio x and the average value X (bar) by the following equation 4. The difference R between the maximum value X (max) and the minimum value X (min) is calculated. The average value X (bar) may be the average value X (bar) a in one image data or may be the average value X (bar) b in a plurality of image data, but in this embodiment, the average of the ratio x As the value X (bar), the average value X (bar) b of each product calculated by the equation 3 is used, and the image data D calculated by the equation 2 is used as the maximum value X (max) and the minimum value X (min). The average value X (bar) a for each is used. If either the calculated average value X (bar) or the difference R is outside the predetermined range, the processing process is abnormal. If the average value X (bar) and the difference R satisfy the predetermined range, the processing process is normal. To be notified. The predetermined range is the average value X (bar) in the range from the upper management limit value X (bar) UCL to the lower management limit value X (bar) LCL of the average value X input to the management value input unit P2a. Yes, the difference R is a range from the upper management limit value RUCL to the lower management limit value RLCL.

  Further, as shown in FIG. 10, the process monitoring means m4 displays a control chart including the average value X (bar), the difference R, and each control value (UCL, LCL, CL) on the control chart display screen P3 in a tabular form or Display in graph format. The inspector can analyze the control chart and detect a process abnormality or the like from the generated control chart, for example, when a graph continuously rises or falls, predicts a process process abnormality.

(Usage example 1)
Below, the usage example 1 of the quality evaluation / process monitoring system Sys of a chemical conversion film is demonstrated. FIG. 11 is a diagram illustrating a first usage example. In use example 1, the imaging means 1 and the visual confirmation means 2 are connected to the chemical film quality evaluation / process monitoring system Sys, and the mounting table 3 on which the product K to be inspected is placed in the imaging direction of the imaging means 1. Is installed.

  The imaging means 1 is a microscope, an electron microscope, or the like, and generates image data D by imaging the chemical conversion film surface of the product K. The imaging means 1 is fixed to the tip of an arm 3 a having a predetermined height from the mounting table 3 with the lens facing the mounting table 3. The arm 3a is detachably attached to the mounting table 3, and the position of the imaging means 1 can be adjusted in the horizontal direction and the vertical direction.

  At the time of imaging, imaging is performed in a state where a light beam (not shown) such as a light irradiates the surface of the chemical conversion film. FIG. 12A shows a case where the imaging region of the chemical conversion film surface is irradiated from above (substantially perpendicular), FIG. 12B shows a case where irradiation is performed obliquely upward (approximately 45 degrees obliquely upward), and FIG. It is a figure which shows the image data D of the chemical film surface at the time of irradiating from a side direction (substantially horizontal direction). The outline of the crystal grains is clear when irradiated from the side direction (substantially horizontal direction) as compared to the case of irradiation from the upward direction and obliquely upward direction. Therefore, from the viewpoint of clarifying the outline of the crystal grains, it is preferable that the light beam is irradiated from the side (substantially horizontal direction) with respect to the chemical conversion coating surface, which is one of the features of the present invention.

  The visual confirmation unit 2 is a computer including a display unit such as a liquid crystal panel and a storage unit such as a hard disk. The image data D imaged by the imaging means 1 is displayed on the display means of the visual confirmation means 2, stored in the hard disk, and read into the chemical conversion film quality evaluation / process monitoring system Sys for use. The visual confirmation means 2 enables visual quality evaluation and process monitoring as well as evaluation by the chemical film quality evaluation / process monitoring system Sys, and can improve reliability.

(Usage example 2)
FIG. 13: is a figure which shows the usage example 2 of the quality evaluation / process monitoring system Sys of a chemical conversion film. The chemical film quality evaluation / process monitoring system Sys1 is connected to another computer 4 via a network NET such as the Internet. The chemical film quality evaluation / process monitoring system Sys receives image data D captured at a remote location from another computer 4 via a network NET such as the Internet, performs quality evaluation and process monitoring, and evaluates the quality. (Pass / Fail) and processing process monitoring results (normal / abnormal) are transmitted via the network NET.

  The chemical film quality evaluation / process monitoring system Sys may be used alone. In this case, the image data D is imaged by a separate imaging means and stored in a storage medium such as a compact disk, and the chemical film is obtained. The quality evaluation / process monitoring system Sys may read the image data D from a compact disc or the like.

(Evaluation method 1)
Below, the evaluation method using quality evaluation / process monitoring system S2 of this chemical conversion coating film is demonstrated. FIG. 14 is a schematic flowchart showing an operation of the chemical film quality evaluation / process monitoring system Sys. (Step 1: Crystal Grain Extraction Step) First, the quality evaluation / process monitoring system Sys of the chemical conversion film extracts the crystal grains of the chemical conversion film included in the image data D. For example, among the objects included in the image data D, the color is brighter than a predetermined value, the size of the object (including the area) is included in the predetermined range, and the shape of the object is the area, the primary moment, and the secondary moment. An object whose ratio x of the major axis length Ld to the minor axis length Sd of the elliptical shape when replaced with the same elliptical shape falls within a predetermined range is extracted as a crystal of the chemical conversion film. (Step 2: Evaluation characteristic information acquisition step) Evaluation characteristic information serving as a judgment index of the film quality of the chemical conversion film is acquired from the image data from which the crystal grains of the chemical conversion film have been extracted. For example, the ratio x is calculated for the crystal grains of the chemical conversion film extracted by the crystal grain extraction means. After the characteristic information acquisition step (Step 2), the process may proceed to the quality notification step (Step 3-1) or the process monitoring step (Step 3-2). (Step 3-1: Quality Notification Step) It is determined whether or not the judgment condition that the evaluation characteristic information is input is satisfied, and the quality of the film is notified. For example, when the average value X (bar) of the calculated ratio x is within a predetermined range, the film quality is good, and when it is outside the predetermined range, it is notified that the film quality is poor. (Step 3-2: Process monitoring step) It is determined whether or not the determination condition for inputting the characteristic information is satisfied, and the normality or abnormality of the process is notified. For example, when the average value X (bar) and the difference R of the calculated ratio x are within a predetermined range, the processing step is normal, and when one or both are out of the predetermined range, the processing step is abnormal. Notify that there is. Since each step corresponds to each means of the chemical conversion film quality evaluation / process monitoring system Sys, details are omitted.

(Evaluation method 2)
The visual quality evaluation / process monitoring method will be described below without using the chemical conversion film quality evaluation / process monitoring system Sys. The inspector visually observes the enlarged image of the crystalline chemical conversion film to be inspected, and observes the appearance of the crystals of the chemical conversion film. The enlarged image is an image captured by an imaging means such as a microscope and displayed on a display device in real time, image data stored in advance in a computer or the like, image data received via a network such as the Internet, etc. It is. The appearance of the chemical conversion film crystal is, for example, the ratio x of the long axis length Ld to the elliptical short axis length Sd. The inspector may only grasp the tendency of the ratio x, but if the average value X of the ratio x is calculated for a plurality of crystal grains, the reliability of quality evaluation and process monitoring becomes high.

  Next, the inspector judges the quality of the film from the crystalline state and monitors the processing process. For example, in the method of grasping the tendency of the ratio x, when the ratio x tends to be large, it is determined that the film quality is good or the process is normal, and when it is small, it is determined that the film quality is poor or the process is abnormal. According to this evaluation method, even if a dedicated chemical conversion film quality evaluation / process monitoring system is not introduced, the quality evaluation and process monitoring of the film can be performed with a general-purpose microscope.

(Example)
Below, the Example at the time of using the quality evaluation / process monitoring system Sys of this chemical conversion film in the state of the usage example 1 is described. The object to be inspected is a metal part K on which a zinc phosphate-based film that is a kind of a crystalline chemical conversion film is formed. As the evaluation characteristic information, the crystal grain shape of the chemical conversion film is replaced with the same elliptical shape with respect to the area, the primary moment and the secondary moment, and the ratio x between the short axis length and the long axis length of the elliptical shape is used. .

  The production of metal parts has the following line processes: degreasing → water washing → pickling → water washing → surface conditioning → chemical conversion treatment → water washing → hot water washing → film quality evaluation → painting → coating film quality evaluation. The film inspection system Sys of the present invention is disposed in the film quality evaluation process. In the chemical conversion treatment, a crystalline zinc phosphate coating is formed by treating the metal surface with a treating agent. In the chemical conversion treatment step, the metal parts are immersed in a zinc phosphate-based treatment liquid (including a zinc phosphate treatment liquid and an accelerator added thereto) to form dense zinc phosphate insoluble crystals. Zinc phosphate contained in the zinc phosphate treatment liquid is a water-soluble compound, but the zinc phosphate film formed after the treatment becomes insoluble white crystals whose composition is modified. In addition, not only the dipping method but also a spray method, a brush coating method, or a roll coating method may be used.

  The chemical conversion film quality evaluation / process monitoring system Sys includes a database DB. The database DB includes image data D, information for identifying metal parts (product number, etc.), film formation time (year / month / day time), positional information of the imaged region, crystal grain extraction conditions, ratio x, average of ratio x It has items such as value X (bar) a, average value X (bar) b, judgment condition of film quality, difference R, control value of X (bar) control chart, control value of R control chart.

  First, the inspector creates image data D of a metal part to be inspected. Specifically, a metal part having a chemical conversion film formed thereon is placed on the mounting table 3 in the film forming line, and the surface of the metal part is formed in a plurality of regions (in this embodiment, the cylindrical metal part K by the imaging means 1). The surrounding 8 locations) are imaged, and a plurality of obtained image data D1,..., D8 are stored in the hard disk of the visual confirmation means 2. Each of the image data D1,..., D8 is stored together with time information indicating the date and time of film formation, area position information, and information (product number etc.) specifying a metal part.

  When the inspector starts the chemical film quality evaluation / process monitoring system Sys, a display screen P1 (FIG. 7) is displayed. When the inspector designates one image data D1 in the image designation portion P1a, the chemical film quality evaluation / process monitoring system Sys displays the designated image data D1 in the image data display portion P1b of the display screen.

  The inspector inputs the extraction conditions (the crystal color, the maximum and minimum values of the crystal area, the maximum and minimum values of the ratio x) to the extraction condition input unit P1c, and the film quality is determined to be good or bad to the determination condition input unit P1e. A predetermined range (minimum value X (min) and maximum value X (max) of average value X (bar)) is input. The quality evaluation / process monitoring system Sys of the chemical conversion film stores the extraction condition and the judgment condition in the database DB, and enables automatic display from the next image data D2.

  The chemical film quality evaluation / process monitoring system Sys starts the film quality evaluation for the designated image data D1. Specifically, the crystal grain extraction unit m1 extracts the conversion coating crystal contained in the image data D1 based on the input extraction condition, and the index acquisition unit m2 calculates the ratio x for the extracted crystal grain. The evaluation characteristic information is acquired by the above, and the quality notification means m3 calculates the average value X (bar) a for the acquired evaluation characteristic information (ratio x), and the average value X (bar) is input to the determination condition input unit P1e. “OK” indicating that the coating quality is good if the judgment value is satisfied within the range of the minimum value X (min) to the maximum value X (max), and if the condition is not satisfied, it indicates that the coating quality is poor. “NG” is displayed on the evaluation result display portion P1f. The quality evaluation / process monitoring system Sys of the chemical conversion film stores the ratio x and the average value X (bar) a in the database DB and displays them on the analysis result display unit P1g. Since the image data D1 is one of a plurality of image data D1,..., D8 obtained by imaging different areas of one inspection object, the film quality evaluation is performed for only one area for one inspection object. It will be done.

  The inspector clicks the “Continue” button when there is image data D in another region for the inspection target. The quality evaluation / process monitoring system Sys of the chemical conversion film sequentially calculates the average value X (bar) a for each of the image data D2,..., D8 for each of the other image data D2 to D8 by means of each means m1, m2, m3. The film quality is evaluated.

  From the evaluation result notified for each area (image data D1, D8) by the quality evaluation / process monitoring system Sys of the chemical conversion film, the inspector determines whether the metal part to be inspected is a non-defective film as a whole. Judge whether it is a non-defective product. For example, if the result “NG” indicating that any one of the image data D1,..., D8 is poor in film quality is output to the evaluation result display section P1f by the chemical film quality evaluation / process monitoring system Sys, metal. Even if it is determined that the entire part is a defective film product or some image data whose evaluation result is a defective film quality is included, the entire metal part is determined to be a good film product. How many image data of the film quality defect are allowed may be dealt with at any time according to the degree of film quality required for the entire metal part to be inspected.

  When the inspector clicks a process monitoring button (not shown), the chemical film quality evaluation / process monitoring system Sys displays a display screen P2. The inspector inputs the management values (CL, UCL, LCL) of the X (bar) control chart and the R control chart in advance in the management value input part P2a of the display screen P2. The management value is a value calculated in advance by experiments. The quality evaluation / process monitoring system Sys of the chemical conversion film stores the management value in the database DB in association with the name of the metal part.

  When the inspector designates data from the database DB in the data reading part P2a of the display screen P2, the average value X (bar) a (X1,..., X8 in FIG. 9) and the difference R are automatically inserted in each column. The The process monitoring means m4 calculates the average value X (bar) b and the difference R, displays a control chart in a table format or a graph format (FIG. 10), and notifies the normality of the process if it is within a predetermined range. If it is within the range, a process abnormality is notified.

  When the film evaluation is completed, a coating process for coating the surface of the chemical conversion film is performed. Since film evaluation is image analysis, it does not take time, and the results of quality evaluation and process monitoring are output in real time. Therefore, if the film quality is poor in the film evaluation, it can be returned to the process of forming the film again, and only the film having good film quality can be sent to the coating process. A long-term blank is not required between the film formation process and the coating process for film evaluation, and production efficiency does not decrease.

(A) is a figure which shows the example of the image data of a chemical film with a favorable film quality of a certain product, (b) is a figure which shows the example of the image data of the chemical film with a poor film quality. The figure explaining the evaluation characteristic information of the crystal grain of a chemical conversion film. The figure which shows the research result about the zinc phosphate system membrane of a certain product. The example of the histogram which calculated the average value X (bar) of the said ratio x of a crystal grain for each area | region about several area | regions of a certain product, and represented the occurrence frequency of the average value X (bar). The figure explaining the situation which misextracted the several crystal grain which overlapped as one crystal grain. The conceptual diagram explaining the quality evaluation / process monitoring system of the chemical conversion film of the 1st Embodiment of this invention. The display screen of the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment. The display screen of the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment. The display screen of the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment. The display screen of the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment. The figure explaining the usage example 1 of the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment. When (a) is irradiated from above (substantially perpendicular) to the imaging region of the chemical conversion film surface, (b) is irradiated from obliquely upward direction (approximately 45 degrees obliquely upward direction), and (c) is lateral direction. The figure which shows the image of the chemical conversion film surface at the time of irradiating from (substantially horizontal direction). The figure which shows the usage example 2 of the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment. The figure which shows the flowchart of the quality evaluation / process monitoring method of the chemical conversion film using the quality evaluation / process monitoring system of the chemical conversion film of the said embodiment.

Explanation of symbols

Sys quality conversion coating quality evaluation / process monitoring system m1 crystal grain extraction means m2 evaluation characteristic information acquisition means m3 quality notification means m4 process monitoring means P1, P2, P3 display screen P1a image designation part P1b image data display part P1c extraction condition input part P1d Measurement result display unit P1e Judgment condition input unit P1f Evaluation result display unit P1g Analysis result display unit P2a Management value input unit P2b Data input unit D Image data

Claims (2)

A crystalline zinc phosphate coating formed by treating a metal surface with a treating agent, from a plurality of crystal grains included in image data obtained by imaging the phosphate zinc coating with a microscope In the zinc phosphate coating quality evaluation system that evaluates the quality of zinc phosphate coating ,
Wherein each crystal grain shape, replaced with the same oval shape for the area and the primary moment and secondary moment, and calculates the ratio x of the length Ld of the major axis to the length Sd of the minor axis of the elliptical shape, the respective the average value X of the ratio x calculated for grain (bar) is the case where more than the predetermined value notifies quality Ru good der, if it is otherwise to notify quality is bad A quality evaluation system for zinc phosphate coatings . For a crystalline zinc phosphate coating formed by treating a metal surface with a treatment agent, from a plurality of crystal grains included in image data obtained by imaging the phosphate zinc coating with a microscope In the process monitoring system for zinc phosphate coating , which monitors the process of zinc phosphate coating ,
For each piece of image data of the plurality of pieces of image data, the shape of each crystal grain is replaced with the same elliptical shape with respect to area, primary moment and secondary moment, and the length of the long axis with respect to the short axis length Sd of the elliptical shape The ratio x of the length Ld is calculated , the average value X (bar) a of the ratio x is calculated for each image data, and the average value X (bar) a of the calculated plurality of image data X ( bar) b, and the difference R between the maximum value X (max) and the minimum value X (min) of the calculated average value X (bar) a of the plurality of image data, and the average value X (bar) b The upper control limit value X (bar) UCL and lower control limit value X (bar) LCL and the upper control limit value RUCL and lower control limit value RLCL of the difference R are shown in real time in the X (bar) -R control chart A process monitoring system for zinc phosphate coating treatment , characterized in that

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