JP4218037B2 - Detection device for defective part of specimen - Google Patents

Description

  The present invention relates to various raw materials, semi-finished products, defect portions including cracks on the surface or inside of the product or adhesion of foreign substances on the surface with non-contact and high detection accuracy, and further, such as subject defect portions that can be detected with high efficiency. The present invention relates to a detection device.

  Conventionally, inspection of the presence or absence of surface or internal cracks of metal, ceramic products, and other products is required in various processes during product manufacture. As methods for detecting a defective portion of these articles, methods such as an appearance inspection using visible light, an X-ray transmission test, and an ultrasonic flaw detection test have been conventionally known. In the X-ray transmission test, defect detection is performed by irradiating a subject with X-rays and analyzing the X-ray transmission rate. In the ultrasonic flaw detection test, a probe is brought into contact with a subject or immersed in a liquid to transmit an ultrasonic wave, and a reflected wave is analyzed to detect a defective portion. In this regard, for example, Patent Document 1 and Patent Document 2 disclose a defect detection method for ceramics or glass products.

JP 59-217139 A Japanese Patent Laid-Open No. 5-142172

  The detection method of Patent Document 1 is to cool a silicon-based ceramic sintered body after infrared irradiation or heating, measure the infrared amount distribution during the cooling, and detect a defective part. In the infrared detection of the surface of the subject in the state, since the heat distribution is relaxed, the defective part is hard to be clarified, and after heating, it is inspecting the article being allowed to cool, so it takes time for the whole inspection, and the industrial There is a problem that it is difficult to put into practical use in a process that requires mass inspection processing of products. Further, Patent Document 2 discloses a method for detecting defects in a glass bottle. The appearance of a glass bottle in a high-temperature state immediately after molding is photographed with an infrared camera, and the temperature distribution of the resulting image is image-processed to make it isothermal. A line is calculated, and the pass / fail judgment is performed by utilizing the fact that the isotherm intersects the defective part isotherm. However, even in the detection method of Patent Document 2, as in the case of Patent Document 1, it is a detection from the temperature distribution in the gradual temperature drop state of the whole subject that is being allowed to cool after heating, after all, There was a point in which a defective part was hard to be revealed and in terms of detection accuracy. In addition, the method of Patent Document 2 is an application example for a bag that is continuously conveyed immediately after molding, and has a disadvantage that can be adopted only for a high-temperature melt-molded product or the like. In addition, the isotherm does not always intersect with the defective part or the like, and there are variations in the determination result, and the reliability of the detection accuracy is unstable.

  The present invention has been made in view of the above-described conventional problems, and one object of the present invention is to detect a defective portion of the object accurately and reliably and to be applied to industrial continuous processing. An object of the present invention is to provide a detection device for defective portions and the like.

In order to achieve the above-mentioned object, the present invention is a heating cradle that is transported and moved by a transport device, and is mounted with a temperature-adjustable heater 128 (130, 136), and the flat surface 126 that is the upper surface is heated. On the heating cradle 124 for receiving the subject flat plate R on the plane, the subject flat plate that is detachably positioned on the heating cradle and heated by surface contact with the heating cradle, and the heating cradle 124 Positioning means 127 for determining the position of the object flat plate R to be placed, the object flat plate R which is detachably positioned on the heating receiving table and heated by surface contact with the heating receiving table, and the moving heat receiving during movement A cooling device 14 that cools the subject flat plate R on the table 124 from the upper side by blowing a cooling gas in a non-contact manner, and an infrared detector that detects infrared rays emitted from the subject during simultaneous heating and cooling of the subject flat plate R 16 and a subject including Composed of the detection device 10 Recessed portion, and the like. By simultaneously heating and cooling the subject, the amount of infrared radiation from the subject is increased, and the accuracy of detecting the presence or absence of defective portions is improved in continuous processing of a large number of articles. Since the heating and cooling temperatures can be set arbitrarily, an arbitrary temperature difference can be formed, and a continuous test process can be performed by setting a reference temperature by performing a preliminary test for each subject. In addition, by identifying a temperature difference when identifying a defective part or the like by image processing via infrared radiation amount detection, the detection becomes more reliable and the detection accuracy and further the part detection accuracy of the defective part or the like is greatly improved. .

At that time, the specimen flat plate R is made of an iron-based sintered body product, and the heating by the heating cradle 124 causes the surface temperature of the iron-based sintered body product as the specimen placed on the upper surface to be 60 ° C. to 120 ° C. The temperature may be set to a temperature range of ° C. There is a large difference in the amount of radiated infrared rays between the defective portion and the normal portion, and the lowest possible temperature range is set within that range.

  The infrared detection means (16) may detect infrared rays emitted from the subject while moving relative to the subject, and contributes to continuous processing and improvement in processing efficiency.

  In addition, it is preferable that a fluid (Ir) that causes opposite thermal effects to be applied to the subject R sequentially from the front side in the traveling direction of the moving subject to the rear side. For example, in a configuration in which a cooling fluid is sprayed on the upper surface side of a subject while heating the subject while being transported and moved, the fluid is simply ejected at a required injection amount and the subject is moved in a predetermined direction. It is possible to realize a configuration in which conflicting thermal effects are generated from the front side in the traveling direction to the rear side sequentially.

  In addition, the fluid that causes the cooling action may be supplied in a linear shape or a belt shape that intersects the traveling direction of the subject R to be transported and moved.

  Furthermore, the cooling fluid may be applied to the surface of the subject R at a constant flow rate. The temperature control for cooling the fluid can be performed accurately, and the temperature difference can be set freely by simultaneous heating and cooling.

  The cooling means may be composed of a cooling gas supply device 14A having an injection nozzle 144 directed in a predetermined direction that opens continuously or discontinuously.

  The infrared detection means (16) may detect the heat distribution state on the upper surface of the subject while the subject R being heated and transported by the heating / conveying device 12A is being cooled by the cooling device.

  In addition, the subject R is composed of a plate-like object having front and back surfaces, and it is preferable that opposite thermal actions are applied to the front and back surfaces. For example, when it is placed on a heating table to cause a thermal action on one side, the surface side in contact with the table is, for example, the back surface, and the side facing outward is the surface.

  As for the cooling and heating actions applied simultaneously, either of the cooling or heating may be applied so as to cool or heat at least approximately the entire surface of the subject R.

  In addition, regarding the cooling and heating operations applied simultaneously, it is preferable that the temperature applied to the subject R can be adjusted for either or both of them.

  Further, the heating / conveying device 12A or the cooling / moving device may have an adsorption mechanism 125 that detachably adsorbs the subject by a suction means including a magnetic force and an air suction force.

  In the present invention, the temperature distribution on the surface of the subject is measured by detecting the amount of infrared rays emitted from the subject while simultaneously heating and cooling the subject R, and the subject's surface is measured based on the temperature distribution. Defects etc. (40, 50) are detected.

An isotherm may be displayed on the monitor screen based on the surface temperature distribution of the subject, and a tomographic display of the isotherm may be displayed on the monitor screen when a defective portion is detected and determined.

  According to the detection apparatus for a defect portion or the like of the subject of the present invention, the first means (12, 14) for heating or cooling the subject is opposite to the first means simultaneously with the heating or cooling by the first means. The second means (14, 12) for cooling or heating the subject to apply the thermal action of and the infrared detecting means (16) for detecting infrared rays emitted from the subject during simultaneous heating and cooling of the subject Therefore, by subjecting the specimen to heating and cooling at the same time, a certain temperature difference field is generated and further maintained, for example, in the iron-based sintered product. The heat transfer becomes a certain size, and the detection accuracy of the defect portion or the like can be greatly improved. That is, by simultaneously heating and cooling, the temperature difference can be clearly set and the detection function can be effectively performed. Further, it can be effectively applied to a certain amount of continuous detection processing. In addition, by identifying a temperature difference when identifying a defective part or the like by image processing via infrared radiation amount detection, the detection becomes more reliable and the detection accuracy and further the part detection accuracy of the defective part or the like is greatly improved. be able to.

  In addition, the infrared detection means (16) is configured to detect infrared rays emitted from the subject while moving relative to the subject, thereby specifically improving continuous processing of the subject and processing efficiency. Can be realized.

  In addition, either heating or cooling means directly applies a heating fluid or a cooling fluid to the subject so that the subject can be heated or heated regardless of how the subject is transported in non-contact detection. The cooling thermal action can be reliably applied to the subject, and the degree of freedom of the subject transport method and specific mode is increased.

  Further, if any of the means for heating or cooling comprises a heating / conveying device or a cooling / moving device in which the subject is detachably mounted on the upper surface and moved, the material supply structure for examining or detecting the subject is extremely Easy to do.

  In addition, the fluid that causes the heating or cooling action is supplied in a linear shape or a belt shape intersecting the traveling direction of the subject to be transported and moved, thereby cooling the subject by jetting from the jet nozzle. It is possible to efficiently perform the thermal action on.

  Further, according to the method for detecting a defect portion or the like of the present invention, the temperature distribution on the surface of the subject is measured by detecting the amount of infrared rays emitted from the subject while simultaneously heating and cooling the subject, Since the configuration is such that a defect portion or the like of the subject is detected based on the temperature distribution, a temperature difference can be set freely, and a fault can be detected by specifying a tomography by a change in heat flow. Further, by simultaneously heating and cooling, the temperature difference can be clearly set and the detection function can be effectively performed.

In addition, an isotherm is displayed on the monitor screen based on the surface temperature distribution of the subject, and when the defect portion is detected and determined, a tomographic display of the isotherm is displayed on the monitor screen. Simultaneously with the detection determination of the part or the like, it becomes easy to specify the defective part.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The present invention is a detection apparatus and a detection method for a defect portion of an object that can accurately detect a defect portion of the object with high accuracy and can be applied to industrial continuous processing, and the best embodiment thereof. For example, a detection device and a detection method for a defective portion of a thin plate-like iron-based sintered product will be described. By the way, as one of the specific articles, iron-based sintered products (for example, steel with ferrite phase, cast iron products) of thin discs are used in automobiles, industrial machinery, robots, factory facilities, measuring instruments, etc. The application part having the drive part is frequently used in the rotation control part corresponding to the amount of movement by the drive, and there is a great need for industrial parts.

  FIG. 1 to FIG. 5 show a detection apparatus for detecting a defect portion or the like of an object R, which is a thin plate-like iron-based sintered product according to an embodiment of the present invention. The thin plate-like iron-based sintered body product as an object in this embodiment is, for example, a sheet having a thickness of 3 mm and a size of about 50 mm × 50 mm in length and width. FIG. 1 is a diagram illustrating a schematic configuration and a usage state of a detection device 10 such as a defective portion of a thin plate-like iron-based sintered product (R) according to an embodiment. In the drawing, the subject R is heated from the lower surface side. In this state, the cooling fluid is supplied from the upper side at the same time, and the temperature difference image is detected while detecting the infrared rays emitted from the subject while forcibly forming a temperature difference. By performing the detection, the defective portion of the subject is detected from the tomographic state of the isotherm that has been revealed in the defective portion.

  In FIG. 1, a detection device 10 such as a subject defect portion includes a heating device 12 that heats a subject R, a cooling device 14 that simultaneously cools the subject R, and infrared rays emitted from the subject R at that time. And an infrared detecting device 16 for detecting. In the present embodiment, the heating device 12 is a first means for heating the subject R, and the cooling device 14 applies a cooling action that is a thermal action opposite to the first means at the same time as the heating by the heating apparatus. Therefore, it is a second means for cooling the subject R as much as possible.

  The heating device 12 is an infrared radiation amount increasing means for heating the subject R to increase the temperature of the subject R itself and increasing the amount of infrared radiation, and is directly brought into contact with a heating device that radiates heat directly. In addition to heating by direct heat conduction performed by heat conduction, a method of heating by spraying a gas, liquid, or other heating fluid, and heating via electromagnetic waves or the like are included.

  In the present embodiment, the heating device 12 is configured as a heating / conveying device 12 </ b> A that places the subject R on the upper surface so as to be detachably transported and simultaneously heats the subject R. That is, in this embodiment, the heating device heats the lower surface side of the subject R. Further, the subject is placed and supported on the upper surface side. The heating and conveying apparatus 12A includes a conveying apparatus 122 such as a conveying conveyor, and a heating cradle 124 that is arranged and conveyed by the conveying apparatus at an appropriate interval. That is, in the present embodiment, the heating device is a heating cradle in which means for simultaneously heating or cooling the subject is integrally incorporated in the cradle T that is transported to the transport device. Then, the subject is placed on the heating cradle and heated from the lower surface side of the subject in a movable state. Returning to FIG. 1, the heating cradle 124 is means for placing the subject R on the upper surface in a detachable manner and heating the subject from the lower surface by surface contact. In FIG. 3A, the heating cradle 124 has a heat source 128 therein. Specifically, in the drawing, a rod heater 130 is inserted into the heating cradle 124 and connected to a power source (not shown), so that heat is generated by its electrical resistance when energized. The heating source 128 can be adjusted and set with a heating temperature by the first temperature controller 132. By keeping the heating temperature constant, the subject is conveyed while being heated at a constant temperature. The conveyance speed of the subject depends on the cooling ability from above the subject and the detection function of the infrared detection device, but in the present embodiment, for example, 2 mm / sec to 15 mm / sec is preferable. 5 mm / sec to 10 mm / sec is preferable.

  If heating of the iron-based sintered product is increased, cracking of the specimen product may be caused by heating and cooling, and thermal damage to the inside of the product may occur. From this point, the heating temperature is rather as much as possible. It is good to suppress to a low temperature. That is, there is a great difference in the amount of radiated infrared rays between the defective portion and the normal portion, and it is preferable to set the temperature as low as possible within the range. In the present embodiment, the heating by the heating cradle 124 is preferably performed so that the surface temperature of the iron-based sintered product as the specimen placed on the upper surface thereof is in the temperature range of 60 ° C to 120 ° C. More preferably, the surface temperature of the iron-based sintered product to be heated is in the range of 90 ° C to 100 ° C. The bottom surface or the bottom surface and the side surface of the heating cradle 124 are insulated by a heat insulating material 134, so that the influence of heat conduction to peripheral components is blocked and safety is ensured. As the heat source, in addition to the rod heater, for example, a panel heater 136 may be disposed on the lower surface side as shown in FIG.

The heating cradle 124 has a rectangular box-shaped outer shape, and the upper surface is a mounting surface 126 having a uniform plane. The mounting surface 126 is preferably heated through the internal heat source 128 so that the entire surface has a uniform temperature. In the present embodiment, the heating cradle 124 is placed on the transport conveyor, and the subject is placed on the upper surface to be transported and moved. However, the heating cradle itself may be self-propelled. . Note that the subject may be heated in a stationary state. Accordingly, the heating and conveying apparatus 12A has a function of placing the subject R on the upper surface in a detachable manner, conducting and heating the subject by surface contact from the lower surface, and further moving the subject R. By moving the subject R while it is moving, the subject can be heated and transported at the same time, and defective parts can be detected efficiently and in a short time in a production line that needs to process a certain amount in a concentrated manner. Can be done. Further, since the heating while moving the object R, the thermal effect of blowing fluid to function effectively.

  Furthermore, in this embodiment, as shown in FIG. 2, a magnetic adsorption unit 127 is installed on the heating cradle 124. The magnetic force adsorbing unit 127 constitutes an adsorption mechanism 125 that detachably adsorbs the subject R by a suction means including a magnetic force or an air suction force. In the present embodiment, a magnet device capable of magnetically attracting a magnetic material is installed on a part or all of the mounting surface 126, whereby the subject R made of an iron-based sintered product can be easily placed on a heating cradle. It can be detachably mounted, and when it is mounted, the position is reliably fixed by the magnetic force action and does not easily shift, and supply, detection, and collection of the subject to the apparatus can be performed easily and reliably. The magnetic force adsorbing portion 127 can use a permanent magnet member or an electromagnet. In addition to the magnetic force, the suction means for the subject's cradle includes air suction force, adhesive force, and other arbitrary suction means. By using this, the subject can be detachably mounted on the cradle. It is preferable to heat and cool simultaneously while transporting in an adsorbed state. For example, in the case of the air suction force, as shown in FIG. 7, a plurality of air suction holes 129a are provided on the upper surface of the cradle, and an air reservoir chamber 129b communicating with these holes in common is provided. The air suction drive device 129d is connected to the air suction drive device 129d through the duct 129c, whereby the subject can be transported and moved from the plurality of air suction holes 129a while adsorbing the subject.

  Returning to FIG. 1, the cooling device 14 is a cooling means for cooling the subject to apply a thermal action opposite to that of the heating device simultaneously with the heating by the heating device 12. In the present embodiment, the cooling means 14 That is, the cooling device 14 is the second means. That is, in the present embodiment, the subject R is heated from the lower surface side of the subject, and at the same time, the upper surface of the subject is cooled from above the subject R. Although the cooling device 14 may be moved, it is not necessarily necessary to move both in detecting the amount of infrared rays of the subject. Rather, the subject is transported while applying a certain thermal action, and at the same time, there is a contradiction. On the cooling (heating) side to which a thermal action is applied, it is more efficient to detect a defective portion or the like as a stationary state. In the present embodiment, the cooling device 14 is fixedly installed on the conveyance movement path of the heating cradle 124 by a fixing mechanism (not shown).

  1 and 2, the cooling device 14 installed above the conveyance movement path of the heating cradle 124 (above the subject in FIGS. 1 and 2), for example, supplies compressed air or low-temperature air by a compressor above the subject. In this embodiment, the cooling device 14 includes a fan 142 as an air supply source, an air injection nozzle 144, and a nozzle port 145. It is comprised from the cooling gas supply apparatus 14A.

  4 and 6, the cooling gas supply device 14 </ b> A is installed so as to add a fluid that causes a contradictory thermal action from the front side in the traveling direction of the moving subject R to the rear side sequentially. . At this time, the nozzle port may be arranged so as to blow down toward the moving direction of the subject as shown in FIG. 6A, or conversely, in the moving direction of the subject as shown in FIG. 6B. You may arrange | position so that cooling air may be blown down in the direction which reverses. In the present embodiment, the injection nozzle 144 of the cooling gas device 14A is installed so as to supply air Ir that causes a cooling action in a linear or belt-like manner intersecting the traveling direction of the subject R to be transported and moved. Has been. As the cooling capacity at this time, it is preferable to cool so that the temperature difference within the upper surface of the iron-based sintered product as an object and the visual field range of the infrared detection means is within 50 ° C., and advantageously It is preferable to cool the upper surface of the iron-based sintered product with a temperature difference of 20 ° C to 30 ° C. Therefore, at least for iron-based sintered products, the cooling air temperature and flow rate should be set based on the above. At this time, the cooling fluid (Ir) is preferably set so as to hit the surface of the subject at a constant flow rate.

  2 and 4, the nozzle port 145 of the ejection nozzle 144 is formed in a long line shape or a band shape in a direction intersecting the traveling direction of the object to be transported, and an opening is formed continuously or discontinuously. Is provided. The opening of the nozzle port 145 is set in such a direction that air or gas is blown down from a position above the object to be transported, as shown in FIG. A gap width of about 1 mm to 10 mm is set between the nozzle port 145 and the subject R, for example, and simultaneous cooling and cooling are effectively performed by ejecting these cooling (heating) fluids to the subject at a close distance. I can do it. The interval between the nozzle opening and the subject R is not limited to the above, and can be arbitrarily set according to the fluid temperature, the flow velocity, the flow rate, and the like. The nozzle opening 145 may be sprayed so as to blow down at a right angle from above toward the surface of the subject. However, after the cooling fluid is sprayed on the surface of the subject, the surface of the subject is scanned. It is good to inject so that it may spread in a strip shape. By spraying the cooling fluid onto the upper surface of the subject heated from the lower surface in a plane with a certain spread in this way, a wide range of dose detection by the infrared sensor can be secured, and the detection accuracy is improved. obtain. In addition, it is possible to secure the degree of freedom of attachment on the sensor side when detecting the dose by the infrared sensor, the ease of setting the target position of the sensor, and the degree of freedom of setting the visual field range by the infrared camera. In addition, although the nozzle port 145 of the cooling device of this embodiment is a slit-like opening that is long and continuous in one direction as shown in FIG. 5A, a plurality of long holes are used as shown in FIG. 5B. It is good also as a structure which has arrange | positioned linearly and discontinuously, and it is good also as a structure which has arrange | positioned several round holes linearly and discontinuously like FIG.5 (c).

  In the present embodiment, although not shown, a second temperature adjusting device for adjusting the cooling fluid blowing temperature of the cooling device is provided, and the second temperature adjusting device is connected to the control device to adjust the temperature on the heating side. It is preferable that the temperature of the cooling fluid by the device 132 and the cooling device can be adjusted, and the temperature difference between the cooling performed simultaneously with the heating can be variably set. For detection according to the type and characteristics of the subject Conditions for obtaining an optimal amount of infrared radiation can be set.

  In the present embodiment, the range in which the compressed air and the low-temperature air are blown when the upper surface of the iron-based sintered product placed on the heating cradle 124 is cooled by the spray nozzle 144 is shown in FIG. Is set to cool a range of about 1/3 of the visual field range. In this embodiment, the data captured via the infrared camera is subjected to isotherm processing by image processing so that the isotherm is always displayed on the display device, and when the surface temperature fluctuates in a defect portion or the like, the isotherm band Is displayed in a state of being shifted in a tomographic shape. Therefore, by setting such a cooling range by low-temperature air and a visual field range by the infrared detection means, the detection accuracy is maintained particularly in the operation of continuously detecting the subject while moving it in a certain direction. Can do. The cooling fluid (heating fluid in the case of cooling the lower surface of the subject) is applied to the surface of the subject at a constant flow rate. Thereby, stable isotherm display by image processing becomes possible, and at the same time, it becomes easy to visually detect an abnormal temperature distribution state in a defective portion or the like.

1 and 2, the infrared detection device 16 is an infrared detection means for detecting infrared rays emitted from the subject during simultaneous heating and cooling of the subject R. In this embodiment, the subject R is the front and back surfaces. The opposite thermal actions are applied to the front and back surfaces. The infrared detecting means detects the heat distribution state on the upper surface of the subject while the subject heated and transported by the heating / conveying device 12A is being cooled by the cooling gas supply device 14A. In the present embodiment, the condensing unit of the infrared detection device is disposed above the subject R, and the amount of infrared rays emitted from the subject on the lower side is measured to detect the presence or absence of a defective portion or the like.

In the present embodiment, the infrared detection device 16 determines whether or not there is a defective portion based on the data from the infrared imaging device 162 and the infrared imaging device, and outputs a signal to the outside when there is, and the display device 18. A control device 20 connected to the cooling device 14 and a display device 18 that displays an image based on image data from the infrared imaging device according to an instruction from the control device 20 and visually displays a defective portion or the like.

In the present embodiment, the infrared imaging device 162 includes an infrared thermograph (infrared thermography) that measures the temperature distribution based on the amount of infrared energy emitted from the subject, and an infrared camera. The infrared imaging device 162 includes, for example, a condenser lens 164 as an optical system, a detection element such as a pyroelectric element, an amplification circuit, an A / D conversion circuit, a temperature conversion, an image processing device, and the like, and infrared radiation from a subject. Energy is detected, and a temperature distribution from the data is generated as image data.

The control device 20 determines the presence / absence of a defective portion or the like based on the image data of the infrared energy of the subject from the infrared imaging device, and outputs a signal to the outside when it is present. In this embodiment, the isotherm data is calculated and generated from the image data of the infrared imaging device 162 to generate a CRT, A plurality of strip-shaped isotherms having a required temperature difference width are displayed at a required interval on a display device 18 such as a display device including a liquid crystal monitor. The control device 20 is electrically connected to the air supply drive fan 142 of the cooling device 14, and acquires infrared data from the infrared imaging device in a state where the cooling device is driven to cool the upper surface side of the subject. To control. Note that the control device 20 is connected to a heating temperature adjusting device 132 by the subject heating device or a temperature adjusting device at the time of configuring the cooling device with a compression pump, and a temperature range by simultaneous heating and cooling set in advance. May be maintained, and detection by an infrared detecting means may be performed. Further, the control device 20 may have a function of being connected to the cooling device 14 and setting the amount of cooling fluid to be blown by the cooling device 14 by an external operation.

In the above-described embodiment, the infrared detection device 16 is in a fixed state and images the subject in a constant visual field region with a constant visual field range V. Infrared rays emitted from the subject may be detected while relatively moving.

Further, in the present embodiment, the control device 20 separates the object product with the defective portion from the heating cradle 124 based on the determination of the presence of the defective portion based on the image data of the infrared energy, and transports the transport device 122. It is connected to a sorting device (not shown) that is excluded from the path K1 to the other partition side K2, and can detect defects such as scratches continuously with respect to a large number of subjects.

Next, a method for detecting the subject R as an iron-based sintered body product using the detection apparatus 10 such as a subject defect portion according to the present embodiment will be described. In FIG. 1, a plurality of heating cradles 124 are transported to a transporting device 122 such as a transport conveyor at predetermined intervals, and an object R made of a thin iron-based sintered product is formed on the upper surface of the heating cradle 124. Is detachably mounted. The plurality of subjects move, for example, linearly at a constant speed by the transport device. At this time, the subject R is transported and moved in a state in which the subject R is magnetically attracted and securely fixed by the magnetic force adsorbing portion 127 of the heating base. The heating cradle 124 heats the upper surface of the sheet-like iron-based sintered body product through a heat source, and the surface temperature of the sheet-like iron-based sintered body product is, for example, about 90 ° C. , Moving on the transport line while maintaining the heating state.

Cooling air is jetted from the jet nozzle 144 of the cooling device 14 such that the temperature difference from the surface temperature of the iron-based sintered product is, for example, about 25 ° C., and the subject R is heated and cooled simultaneously. The temperature of the cooling air is input and set by an external operation unit such as an adjustment dial connected to the control device 20. At this time, the infrared imaging device 162 of the infrared detection device detects the infrared ray L that is condensed by the lens and emitted from the iron-based sintered product R. The infrared detecting device 16 processes the detected infrared data as an apparent temperature distribution. The visual field range of the infrared detection device 16 is at least a movement path of the subject R, and is set as a range in which radiant infrared rays from the entire upper surface of the subject can be detected. An image based on infrared data is updated at predetermined time intervals, and the amount of infrared radiation emitted from the subject surface side as the subject R moves is detected. At the same time, the infrared detection device 16 supplies infrared data to the control device 20.

  When the control device 20 processes the infrared energy image data of the subject from the infrared imaging device and the temperature data exceeds a set reference threshold, a defect is detected as a temperature change due to the presence of a defective portion or the like. The determination result that there is a part is output to the sorting device side. Further, the control device 20 calculates an isotherm based on the image data of the infrared energy of the subject from the infrared imaging device, and outputs the generated isotherm data to the display device 18. The display device 18 receives the isotherm image processing data from the control device 20 and displays a color isotherm image that has been color-coded. The control device 20 further has a cold air temperature control function of the cooling device, and maintains a predetermined set temperature to maintain a temperature difference.

Next, referring to FIGS. 8 to 13, heat transfer in the subject due to simultaneous heating and cooling applied to the subject will be described. FIG. 8 shows the heat transfer on the upper surface of the subject R made of an iron-based sintered product when there is no crack defect as a defect portion, and FIG. 9 is an explanatory view showing the subject R in cross-section at that time. It is. Heat 2 from the heating cradle 124 is always applied to the subject R (FIG. 7), and the applied heat flows into the subject 2A as shown in FIG. At the same time, the upper surface of the subject R is partially cooled (for example, the front side in the traveling direction), so that a temperature difference occurs across the entire upper surface of the subject R, and the high temperature region 3 and the low temperature region 4 are present on the upper surface of the subject R. Is formed. 9, in the temperature distribution of the cross section of the subject R, heat transfer 5 occurs from the high temperature region 3 (subject rear side) to the low temperature region 4 (subject front side) in the surface layer portion, and at the same time, the lower surface of the subject R. Both the heat inflow 2A from the heating cradle side are generated, and a gentle temperature distribution is formed on the upper surface of the subject R.

On the other hand, FIGS. 10 and 11 show a case where there is a crack defect 40. FIG. 10 shows the heat transfer on the upper surface of the subject R when there is a crack defect, and FIG. 11 shows the heat transfer seen from the cross section at that time. In FIG. 10, the heat transfer 5 from the high temperature region 3 to the low temperature region 4 across the defect 40 portion is blocked by the crack defect 40, and a part of the heat 2 from the lower surface of the subject R flows into the low temperature region 2A. The heat transfer 5 from the high temperature region 2 to the low temperature region 3 is blocked. For this reason, at the boundary of the crack defect 40, a larger temperature difference occurs between the high temperature region 3 side and the low temperature region 4 side than a normal subject having no defect portion or the like. Accordingly, it is possible to easily detect the defect portion or the like by utilizing a large temperature difference in the crack defect portion or the like of the subject.

This large temperature difference is formed even when, for example, foreign matter adheres to the upper surface of the iron-based sintered product or other specimen of the present embodiment. FIGS. 12 and 13 explain the heat transfer action during detection when a foreign object is present on the surface of the subject. In FIG. 12, when the entire visual field range of the infrared detector 16 is cooled by the cooling device 14, The temperature of the portion 50 is lower than that of the foreign matter non-adhered portion (normal portion). As shown in FIG. 13, the subject R has a heat inflow 2A from the lower surface, and in the normal portion, the inflow heat reaches the upper surface of the subject, but the foreign matter portion 50 has a thermal conductivity higher than that of the normal portion. Therefore, the heat inflow 2B reaching the upper surface side of the foreign matter portion is small. Accordingly, since the amount of infrared radiation on the foreign material portion 50 is smaller than that of the normal portion, the temperature of the foreign material portion 50 is lower than that of the normal portion. Therefore, by performing the simultaneous heating and cooling processes as described above, a large temperature difference is generated at the boundary between the defective part and the normal part as compared with the normal part, and the image is converted into a temperature distribution image obtained by the infrared detector 16. It becomes easy to process, and defects can be detected reliably and accurately in a non-destructive manner.

As a result, not only crack defects but also foreign matters or the like adhere to the surface of the subject can detect a defective portion or the like using this large temperature difference. Specifically, for example, in the case of a foreign substance, it has been experimentally proved that detection is possible if the size is 0.2 μm square or more. As a detection method when foreign matter is present on the upper surface of the subject R, cooling may be performed while the heating cradle 124 is moved, but cooling air may be used while the heating cradle 124 is stopped in the cooling process. You may make it spray. Also in this case, heating and cooling are performed simultaneously as described above. When cooling is performed with the heating cradle 124 stopped, when compressed air is supplied, for example, the compressed air pressure is preferably 0.1 to 0.7 Mpa, and optimally 0.3 to 0.5 Mpa. Good. In addition, the cooling time at that time is preferably 0.1 second to 1 second, and more preferably 0.3 to 0.7 second. Further, when cooling, it is preferable to cool the entire visual field range of the infrared detecting means.

Next, a method for generating an isotherm image by performing image processing on the heat distribution image obtained from the infrared detection device 16 will be described. In the control device 20, isotherm data is calculated and generated from the image data of the infrared imaging device 162, and a plurality of strip-shaped isotherms having a required temperature difference width are displayed on the display device 18 at a required interval. As an image processing method at the time of detecting a defect, there are a method using an isotherm or a method using differentiation for a temperature difference greatly different from surroundings between pixels. The isotherm shown here is a belt-like line having a required line width drawn on the heat distribution image by setting values in the heat distribution image at regular intervals and replacing all the set values with specific values. It can be displayed as either a straight line or a curved line. The specific value may be any value, but 0 or 1 is preferable.

In the defect detection method using an isotherm, a plurality of isotherms are drawn at a required interval width in the heat distribution image obtained from the infrared detector 16, and the value at the isotherm portion in the heat distribution image is set to 0. The portion other than the isotherm is 1. At this time, the center temperature of each isotherm is 55 ° C. to 85 ° C., and the temperature is drawn in the range of 0.1 ° C. to 0.5 ° C. (corresponding to the line width of the isotherm). In addition, the temperature between adjacent isotherms is preferably drawn at 1 ° C to 5 ° C. Optimally, the center temperature is 65 ° C. to 75 ° C., and the line width range is 0.2 ° C. to 0.3 ° C. with respect to the center temperature, and the temperature between the isotherms is in the range of 1 ° C. to 3 ° C. It is good to do.

FIG. 14 shows a heat distribution image of the upper surface of the subject R as an iron-based sintered product when there is no defect and an isotherm at that time. The isotherms 60 a to 60 c... Displayed in this figure are drawn from the high temperature region 3 to the low temperature region 4 within the visual field range 17 of the infrared detecting device 16 in the cooling process. At this time, the isotherms 60a to 60c... Are drawn as one continuous belt-like isotherm from the outer frame 17A in the visual field range to the opposing outer frame 17A.

In FIG. 15, when the isotherm crosses the defect portion 40, the isotherm 60 a itself is continuous as shown in FIG. 15, but the line width Wa is different between the defect portions 40. That is, the line widths 40Wa, 40Wb, 40Wc,... At the defective part become narrower than the line width of the non-defective part, for example, by inhibiting the heat transfer in the crack part. In addition, the isotherms 60a to 60c... Are displayed in the defective portion 40 so as to be offset from the non-defective portion isotherms. Then, by performing expansion and contraction processing, which is generally known as an image processing method, on the defective portion for each isotherm, the thin line of the defective portion is erased, and from the outer frame 17A as shown in FIG. Discontinuous isotherms 651 to 653 are drawn in which the outer frame 17A is divided into an offset shape due to the presence of a defective portion. That is, one non-defect portion isotherm and the other non-defect portion isotherm with the defect portion 40 as a boundary are displayed in a state of being shifted in a tomographic manner. This discontinuity is determined as a defective part.

Further, as a method of displaying using a differential for a temperature difference greatly different from surroundings between certain pixels, there is an edge detection process. In the heat distribution image obtained from the infrared detection device 16, it is preferable to use processing by the canny method among the known edge detection processing. Due to this image processing, since there is a large temperature difference between certain pixels in the defective portion compared to the normal portion, a line along the boundary of the defective portion is detected.

Next, a specific example of crack defect detection will be shown.
[Example 1]
Here, the case where the iron-based sintered body product R has a crack defect is shown. The thin plate-like iron-based sintered product R is placed on a heating pedestal heated by a rod heater until the surface temperature reaches about 120 ° C. The heating cradle 124 conveys the thin plate-like iron-based sintered product R to the cooling process while maintaining this temperature. At this time, the temperature of the upper surface of the thin plate-like iron-based sintered body product is maintained at about 100 ° C. by heating by the heating cradle 124, and the conveyance speed is 4 mm / sec.

The thin plate-like iron-based sintered product R placed on the heating cradle 124 that is transported at a constant speed by the transport device 122 is cooled without changing the transport speed and the heating temperature from the heating cradle 124 in the cooling process. Go through the process. In the cooling step, compressed air is used as a cooling means, and the flow rate of compressed air injected from the nozzle port of the injection nozzle at this time is about 5 L / min.

The thin plate-like iron-based sintered product R, whose lower surface is heated from the heating cradle and simultaneously cooled by compressed air, emits infrared rays from its upper surface. The infrared rays emitted from the thin plate-like iron-based sintered product R are simultaneously detected by the infrared imaging device 162 in which the range of the visual field area is set to the product R, and the obtained data is detected by the infrared detection device 16 at the pixel Primary image data that has undergone processing such as density, color, texture, and other attributes and regions is generated, and the data is sent to the control device 20. The primary image data obtained by the infrared imaging device is converted into a heat distribution image inside the infrared detection device and used as a basic image for defect detection. In addition, when it does not fit in the visual field range of the infrared detector 16, the infrared rays emitted from the surface of the product R are detected again while passing through the cooling process in the same manner as described above. The conditions of the heating cradle 124 and the cooling device 14 at this time are processed in the same manner as described above.

The control device 20 extracts the target pixel from the obtained heat distribution image by the following method. For example, the basic value is set to 80 ° C., and an additional value is set every ± 4 ° C. with respect to the basic value. Furthermore, numerical values in the range of ± 0.4 ° C. of the respective values with respect to the basic value and the added value are simultaneously extracted. Specifically, assuming that 80 ° C. is a basic value, the added values are 76 ° C. and 84 ° C., and are extracted as much as possible within the range of the thin plate-like iron-based sintered product R in the heat distribution image. Further, for these values, if the temperature is 80 ° C., all values in the range of ± 0.4 ° C. of the basic value and the added value are extracted, such as 80.4 ° C. or higher and 79.6 ° C. or lower. After extraction, replace all values except 0 that are components of the isotherm.

The non-zero value extracted above is used as an isotherm element pixel, and the values of these elements are all replaced with 1. After the replacement, the isotherm is composed of each basic value and a value in a range of ± 0.4 ° C. with respect to that basic value. Therefore, each isotherm is labeled with the same value. Specifically, all values from 79.6 ° C. to 80.4 ° C. are 1 (1), all values from 83.6 ° C. to 84.4 ° C. are 1 (2), and 75.6 ° C. to 76.4 ° C. This is a process of replacing all values up to ° C. with 1 (i) {i = natural number}. By this process, an arbitrary number is assigned to each isotherm.

Degenerate processing is performed on the labeled isotherm. When this isotherm straddles a crack defect, since the isotherm of a crack defect part becomes extremely thin, an isotherm is interrupted by applying a degeneracy process. If there are no defects, there is no break.

Since different numbers are assigned to each isotherm, if there is a pixel with the same number around it, it is determined that there is no defect on the isotherm, and it exists in reverse. Otherwise, it is determined that there is a defect on the isotherm. This process is repeatedly performed within the range of the thin plate-like iron-based sintered product R in the data transmitted from the infrared detector 16.

In the display device 18, an isotherm display image for the visual field range of the imaging device by the above processing is displayed as the product R is moved, and the defective portion can be visually observed on the monitor.

[Example 2]
Next, an example of defect detection by foreign matter adhesion will be shown.

The thin plate-like iron-based sintered product R is placed on a heating cradle heated by a rod heater until the surface temperature reaches about 120 ° C. The heating cradle 124 conveys the thin plate-like iron-based sintered product R to the cooling process while maintaining this temperature. At this time, the temperature of the upper surface of the thin plate-like iron-based sintered body product is maintained at about 90 ° C. by heating by the heating cradle 124.

While being heated by the heating cradle 124, it is transported to the cooling process and temporarily stops in the cooling process. Simultaneously with the stop, the cooling device 14 cools the upper surface of the thin plate-like iron-based sintered product R. The cooling device 14 uses compressed air, the pressure at that time is 0.5 Mpa, the cooling time is 0.3 sec, and the cooling range is the entire visual field range of the infrared detector 16.

The infrared detector (infrared imaging device) detects infrared rays emitted from the surface of the thin plate-like iron-based sintered product R (subject R) simultaneously with the operation of the cooling device. The infrared detection data obtained here is converted into a heat distribution image in the infrared detection device.

The feature of the thermal image in this case is that the value of the foreign matter adhesion range portion is lower than the surrounding value, so that the difference in value at the boundary between the foreign matter portion and its surroundings becomes large. This is because, for example, the heat conductivity of the foreign matter portion made of an organic substance is low, so that the heat inflow to the foreign matter portion is small and the value is lower than the surroundings. In the case of a metallic foreign object, a difference in value appears on the boundary in the same state as described above.

Based on the obtained heat distribution image, image processing for edge extraction is performed. As an edge extraction method used at this time, a generally known canny method is used to extract a boundary line between the foreign substance portion and its surroundings.

Further, the inside of the extracted boundary line is determined as a defect. By this method, the size and position of the foreign matter are clarified.

The determination of the presence or absence of a crack defect or a foreign substance in the above embodiment is performed by an isotherm calculation process, but it is not always necessary to determine the presence or absence through an isotherm or other image processing process. When identification or the like is unnecessary, the presence / absence determination of a defect may be performed by numerical comparison determination with reference data when there is no defect before image processing.

  The above-described detection apparatus and method for detecting a defect portion of an object according to the present invention is not limited to the above-described embodiment, and may be arbitrarily selected without departing from the essence of the invention described in the claims. May be modified.

  The detection apparatus and method for detecting a defect portion of an object of the present invention is effective in a detection apparatus and detection method for a defect portion including various raw materials, semi-finished products, product surface or internal cracks, or adhesion of foreign substances on the surface. It is applicable to.

It is a use condition explanatory drawing including schematic structure of detection apparatuses, such as a subject defect part concerning a 1st embodiment of the present invention. FIG. 2 is an explanatory diagram of an enlarged configuration of a detection device portion such as a subject defect portion in FIG. 1. It is an expansion schematic perspective view of the heating cradle of the detection apparatus of FIG. It is an expansion schematic perspective view of the example of the other heating receiving stand of the detection apparatus of FIG. It is plane explanatory drawing showing the heating receiving stand and cooling injection nozzle of the detection apparatus of FIG. It is a figure which shows the example of the shape of various nozzle openings, and an arrangement | sequence. It is explanatory drawing which shows the fluid injection state for cooling of the detection apparatus of FIG. It is explanatory drawing which shows the other cooling fluid injection state of the detection apparatus of FIG. It is explanatory drawing which shows the other example of the adsorption | suction mechanism of the detection apparatus of FIG. It is an operation explanatory view explaining a heat transfer state about a normal subject of a detecting device, such as a subject defective part concerning a 1st embodiment of the present invention. It is an operation explanatory view explaining a heat transfer state about a normal subject of a detecting device, such as a subject defective part concerning a 1st embodiment of the present invention. It is a perspective action explanatory view explaining a heat transfer state about a subject with a defective part etc. (crack defect) of a device concerning a 1st embodiment of the present invention. It is a section action explanatory view explaining the heat transfer state about a subject with a defective part etc. of a device concerning a 1st embodiment of the present invention (crack defect). It is a perspective action explanatory view explaining a heat transfer state about a subject with a defective part etc. of a device concerning a 1st embodiment of the present invention (foreign matter adhesion defect). It is a section action explanatory view explaining the heat transfer state about a subject with a defective part etc. of a device concerning a 1st embodiment of the present invention (foreign matter adhesion defect). It is a figure explaining the specific example of the isotherm display process by the Example of the apparatus of this invention. It is a figure explaining the specific example of the isotherm display process by the Example of the apparatus of this invention. It is a figure explaining the specific example of the isotherm display process by the Example of the apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Heating 3 High temperature area | region 4 Low temperature area | region 5 Heat transfer 10 Detection apparatus 12 Heating apparatus 12A Heating conveyance apparatus 122 Conveyance apparatus 124 Heating stand 126 Mounting surface 127 Magnetic force adsorption part 132 1st temperature control apparatus 14 Cooling apparatus 14A Cooling gas supply apparatus 144 Injecting nozzle 145 Nozzle port 16 Infrared detector 162 Infrared imaging device 17 Field of view 18 Display device 20 Control device 40 Crack defect 50 Foreign matter portion 60a... Isotherm Wa Line width R Subject L Infrared

Claims (2)

A heating cradle that is transported and moved to a transport device, and a heating cradle that is equipped with a temperature-adjustable heater and that heats a flat surface as an upper surface and receives a specimen flat plate on the flat surface;
Positioning means for determining the position of the subject flat plate placed on the heating cradle;
An object flat plate which is detachably positioned on the heating cradle and heated by surface contact with the heating cradle;
A cooling device that cools in a non-contact manner by spraying a cooling gas from above on a specimen plate on a moving heating cradle;
An apparatus for detecting a defective part of an object, comprising: infrared detecting means for detecting infrared radiation emitted from the object during simultaneous heating and cooling of the object flat plate . The specimen flat plate is made of an iron-based sintered product,
The heating by the heating cradle 124 is performed such that the surface temperature of the iron-based sintered body product as an object placed on the upper surface thereof is set to a temperature range of 60 ° C to 120 ° C. Item 1. An apparatus for detecting a defect portion of an object according to Item 1.

Images