JP2010210270A - Method and device for inspecting flaw of work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect flaws of a work by subjecting the temperature distribution of the heat possessed by the work to image processing, without imparting excessive energy to the work. <P>SOLUTION: At the time of processing in a stage prior to the forwarding of an article 1 to be inspected as a product, for example, the heat produced in shot blast or shot-peening processing is utilized (step S1), to obtain a thermal image (step S2), and the flaw of the article to be inspected is determined, on the basis of the thermal image by computer operation (step S3). An infrared imaging device 3 by infrared thermography is used for acquiring the thermal image, and a control circuit 5 determines the presence of the flaws, on the basis of the obtained heat image data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a workpiece defect inspection method and defect inspection apparatus for inspecting a workpiece defect.

  Conventionally, a workpiece defect inspection method is known in which a workpiece is cooled by a heating device or cooled by a heating device, and the surface temperature distribution of the workpiece is imaged by an infrared camera, and then image processing is performed to inspect the workpiece for defects. (See Patent Document 1).

JP 2007-327755 A

  However, in the above-described conventional defect inspection method, it is necessary to heat or cool the workpiece using a heating device or a cooling device in order to perform image processing of the temperature distribution, and extra energy is applied to the workpiece. This increases the equipment cost.

  Accordingly, an object of the present invention is to perform defect inspection by performing image processing on a temperature distribution without giving extra energy to a workpiece.

  The present invention is characterized in that a temperature distribution based on heat generated when a workpiece is processed is acquired as a thermal image to inspect for the presence or absence of defects.

  According to the present invention, it is possible to perform defect inspection by performing image processing on the temperature distribution of heat held by a workpiece without imparting extra energy to the workpiece.

(A) is a flowchart which shows the inspection process used as the basis of the defect inspection method of the workpiece | work by this invention, (b) is a block diagram which shows the whole structure of the inspection apparatus used for the inspection method of (a). It is a flowchart which shows 1st Embodiment which implements shot blasting or shot peening as a process with respect to the to-be-inspected object in FIG. It is a flowchart which shows 2nd Embodiment which implements a quenching process as a process before shipment with respect to the to-be-inspected object in FIG. It is a flowchart which shows 3rd Embodiment which implements warm forging or cold forging as a process before shipment with respect to the to-be-inspected object in FIG. It is a flowchart which shows 4th Embodiment which implements hot forging as a process before shipment with respect to the to-be-inspected object in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A is a flowchart showing an inspection process which is the basis of a workpiece defect inspection method according to the present invention. The workpiece here is, for example, an inspected object 1 shown in FIG.

  Using the heat generated during processing of the inspection object 1 before shipping the inspection object 1 as a product (step S1), a thermal image is acquired (step S2). Based on this, a defect is determined by computer calculation (step S3). The inspection object 1 that has not been determined to be defective here is shipped after being subjected to rust prevention treatment (step S4) (step S5).

  Specifically, as shown in FIG. 1B, an infrared imaging device 3 is used as a thermal image acquisition unit made of infrared thermography, and the infrared imaging device 3 converts infrared energy emitted from the object 1 to be inspected. The temperature distribution of the surface of the inspection object 1 is detected and acquired as a thermal image. Based on this image data, the control circuit 5 as the defect determination means which is a control means determines the presence or absence of defects by computer calculation, The result is displayed on the display 7 which is a display means.

  The defect of the inspection object 1 is, for example, a flaw, and if there is a flaw, heat easily accumulates in the recess due to the flaw, so that the part with the flaw is hotter than the other part without the flaw. It is easy to become. In addition, in a case where the forging process causes a part of the surface to peel off and the part that has been swollen up overlaps the surface of the inspection object 1, heat tends to be trapped in the overlapped gap. It becomes high temperature.

  As described above, the part where the defect is generated in the inspection object 1 becomes a high temperature with respect to the other part and a temperature difference is generated, and the defect is detected by performing image processing on the surface temperature distribution. be able to. At this time, in this example, the temperature distribution based on the heat generated during processing before the inspection object 1 as a workpiece is shipped as a product is acquired as a thermal image. Without applying energy, the temperature distribution can be image-processed for defect inspection.

[First Embodiment]
FIG. 2 is a flowchart showing a first embodiment in which shot blasting or shot peening is performed as a pre-shipment processing on the inspection object 1 in FIG.

  In other words, by projecting a shot onto the inspection object 1 by shot blasting or shot peening, the surface of the inspection object 1 is surface-treated by physical stimulation. In step S1A, a thermal image is acquired (step S2), and then a defect is determined by computer calculation (step S3). The subsequent steps are the same as those in the flowchart of FIG.

  Thereby, in this embodiment, since the temperature distribution based on the heat | fever which generate | occur | produces in the surface treatment by the physical irritation | stimulation before shipping the to-be-inspected object 1 as a product is acquired as a thermal image, the example of FIG. Similarly, it is possible to perform defect inspection by performing image processing on the temperature distribution without giving extra energy to the inspection object 1.

  In the above-described shot blasting, the oxide scale generated on the surface of the inspection object 1 is removed by heating in the forging process, and the surface of the inspection object 1 is rubbed with a brush in order to remove the oxidation scale. Work (sharpening) may be performed, and a thermal image can be acquired using heat generated at that time. In shot peening, the surface is cured.

[Second Embodiment]
FIG. 3 is a flowchart showing a second embodiment in which a quenching process is performed as a pre-shipment process for the inspection object 1 in FIG.

  That is, the to-be-inspected object 1 is subjected to a quenching process, and heat generated at this time is used (Step S1B) to obtain a thermal image (Step S2), and then defects are determined by computer calculation (Step S1). S3). The inspection object 1 that is not determined to be defective here is transported to the next process (step S6).

  Therefore, in this embodiment, since the temperature distribution based on the heat generated in the quenching process before shipping the inspection object 1 as a product is acquired as a thermal image, the inspection object is similar to the example of FIG. It is possible to perform defect inspection by image processing of the temperature distribution without applying excessive energy to 1.

  In particular, induction hardening (IHQ) is performed as a specific hardening process here. Induction hardening is performed in a state where the inspection object 1 is inserted into the coil. Therefore, as a defect inspection, not only the inspection object 1 is removed from the induction hardening apparatus after the hardening operation but also during the hardening operation. Even so, since the surface of the inspection object 1 can be imaged by the infrared imaging device 3 through the gap between the inspection object 1 and the coil, the quenching operation and the defect inspection operation can be performed simultaneously to shorten the operation time. This can contribute to a reduction in work costs.

  Furthermore, when performing defect inspection during induction hardening work, defect inspection can be performed over the entire circumference by moving the infrared imaging device 3 along the gap between the inspection object 1 and the coil, which is extremely efficient. It becomes possible to inspect the entire periphery of the inspection object 1.

  In addition, as above-mentioned hardening process, not only induction hardening but a carburizing hardening process may be sufficient, for example.

  Further, even after cooling in the quenching process, the inspection object 1 retains heat, so that a defect inspection can be performed.

[Third Embodiment]
FIG. 4 is a flowchart showing a third embodiment in which warm forging or cold forging is performed as a pre-shipment processing on the inspection object 1 in FIG.

  That is, here, using the heat generated in the inspection object 1 after the warm forging or cold forging process (step S1C), a thermal image is acquired (step S2), and then defects are calculated by computer calculation. Determine (step S3). The inspection object 1 that is not determined to be defective here is transported to the next process (step S6).

  Therefore, in this embodiment, since the temperature distribution based on the heat generated by the warm forging or the cold forging before shipping the inspection object 1 as a product is acquired as a thermal image, it is the same as the example of FIG. In addition, it is possible to perform defect inspection by performing image processing on the temperature distribution without giving extra energy to the inspection object 1.

  In warm forging, heat generated by heating the object to be inspected 1 is used, and in cold forging, plastic heat generated during forging is used.

  In particular, here, since the defect inspection is performed after warm forging with a low heating temperature of about 800 ° C. or less for the object to be inspected 1 or cold forging, not only cold forging at room temperature processing but also warm forging. Even so, it is difficult for the oxide scale to be generated on the surface of the object 1 to be inspected. Therefore, it is possible to suppress the erroneous determination by the oxide scale and perform the defect inspection accurately.

  In the third embodiment, after the warm forging or cold forging process, for example, the inspection object 1 is taken out of the mold and the defect inspection is performed, but the mold during the forging process is opened. Sometimes, it is possible to inspect the surface of the inspection object 1 with the infrared imaging device 3 to perform defect inspection. Thereby, defect inspection can be performed at the same time as the forging process, the working time can be shortened, and the working cost can be reduced.

[Fourth Embodiment]
FIG. 5 is a flowchart showing a fourth embodiment in which hot forging is performed as a pre-shipment processing on the inspection object 1 in FIG.

  That is, here, using the heat generated in the inspection object 1 after hot forging (step S1D), a thermal image is acquired (step S2), and then defects are determined by computer calculation (step S1D). S3). The inspection object 1 that is not determined to be defective here is transported to the next process (step S6). In the hot forging, the heat generated by heating the object to be inspected 1 is used as in the above-mentioned warm forging.

  In the hot forging process described above, similarly to the warm forging or cold forging described above, the defect inspection can be performed by imaging the infrared imaging device 3 when the mold during the forging process is opened. In hot forging, since it is heated to a temperature higher than that in warm forging, oxide scale is likely to be generated on the surface of the object 1 to be inspected, but the oxide scale is almost shaken off by the impact during forging. However, accurate defect inspection during processing is possible.

  Further, the removal of the oxide scale described above may be performed by blowing air when the mold is opened, whereby the oxide scale can be removed more reliably and the defect inspection accuracy can be further improved.

  1 Inspection object (work)

Claims (7)

  A defect inspection method for a workpiece in which a temperature distribution of heat held by a workpiece is acquired as a thermal image to inspect for the presence or absence of defects, and a temperature distribution based on heat generated when the workpiece is processed is acquired as a thermal image. A defect inspection method for a workpiece characterized by inspecting for the presence or absence of defects.   The work defect inspection method according to claim 1, wherein the processing on the workpiece is a surface treatment by physical stimulation on the surface of the workpiece.   The work defect inspection method according to claim 1, wherein the work on the work is a quenching process.   The work defect inspection method according to claim 1, wherein the work on the work is a forging process.   4. The work defect inspection method according to claim 3, wherein the quenching process is induction hardening, and the thermal image is acquired during the induction hardening.   The work defect inspection method according to claim 4, wherein the thermal image is acquired when the mold for forging is opened.   A workpiece defect inspection apparatus that acquires a temperature distribution of heat held by a workpiece as a thermal image and inspects for the presence or absence of defects, and acquires a temperature distribution based on heat generated when the workpiece is processed as a thermal image. A defect inspection apparatus for a workpiece, comprising: a thermal image acquisition unit; and a defect determination unit that determines the presence or absence of a defect in the workpiece based on the thermal image data acquired by the thermal image acquisition unit.

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