JP6650379B2 - Surface inspection device, surface inspection method and database - Google Patents

Description

  The present invention relates to a surface inspection device, a surface inspection method, and a database.

  In a mass production site for cast parts, it is necessary to determine whether or not there is a defect after the completion of the casting process and to provide the result to the next machining process. In the casting process, various shapes of defects can be generated both inside and outside due to various factors. In particular, a hot boundary defect generated on the surface of a component may be a starting point of a fatigue crack in an environment where an external load is applied. For this reason, it is important to reliably detect defects in the inspection process after the completion of the casting process and to judge the quality of parts.

  In the conventional inspection process, a manual visual inspection has been mainly performed. However, it is inefficient to perform a 100% inspection of a large number of mass-produced products visually, and the risk of oversight is high. Therefore, there is a growing need for an automatic defect inspection technique that can replace the visual inspection.

  For automatic inspection, a device that efficiently inspects relatively large-sized objects or objects with complicated shapes, such as car body panels, including in-line automatic inspection of planar objects such as electronic boards. Various proposals have been made.

  For example, Patent Literature 1 discloses a technique for inspecting the surface of an object having a curved surface, in which a scanning direction and a scanning speed of an optical sensor are selected based on a cross-sectional curvature of a work to be inspected and a length of the work, A method and an apparatus for selecting a scanning pattern based on the height of a stepped surface portion and a preset work shape data and inspecting a surface defect are described.

Japanese Patent No. 4670180

  When the target of the surface shape measurement is a mass-produced cast product or the like, different types of defects occur depending on the inspection position of the surface. For efficient inspection, it is desirable to control scanning for each surface inspection site according to the type of defect.

  The technique described in Patent Literature 1 changes a scanning direction based on a surface shape of a work, and selects a scanning speed and a scanning pattern based on a cross-sectional shape. However, the technique described in Patent Literature 1 is not a technique for changing a scanning pattern for each part based on the form of a defect. For this reason, when the technique described in Patent Literature 1 is used, the surface of the work is measured uniformly, and an area that does not need to be measured is also measured, which requires time. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to perform a surface inspection of an inspection target with high speed and high accuracy.

  The surface inspection apparatus of the present invention is an apparatus for inspecting the surface of an inspection object, and includes a measurement unit and a control unit, and the measurement unit is movable by a command of the control unit, and the surface inspection is performed. The apparatus sets a scanning condition using the defect information of the inspection object.

  According to the present invention, since the defect information of the inspection object is used, a highly reliable inspection without oversight is possible. Further, according to the present invention, since attention is paid to the defect information of the inspection object, it is possible to omit the measurement of the non-defect part, and it is possible to perform the inspection at a high speed.

It is a figure showing roughly the whole composition of the surface inspection device of the present invention with a structure to be inspected. It is a flowchart which shows the surface inspection method of this invention. FIG. 4 is a diagram illustrating an example of defect information stored in a storage unit. FIG. 4 is a diagram for explaining an example of a method of setting a scanning condition for a defect having directivity. FIG. 4 is a diagram for explaining an example of a method of setting a scanning condition for a defect having no directivity. FIG. 4 is a diagram for explaining an example of scanning control based on scanning conditions set for a defect having directionality. FIG. 9 is a diagram showing measurement points when scanning for a directional defect. FIG. 7 is a diagram for explaining an example of scanning control based on a scanning condition set for a defect having no directivity. FIG. 7 is a diagram showing measurement points when scanning a defect having no directivity. It is a figure which shows roughly the whole structure of the surface inspection apparatus of this invention using the measuring instrument which has a linear measurement range with the structure to be inspected. It is a figure showing roughly the whole composition of the surface inspection device of the present invention using a robot arm with a structure to be inspected.

  The present invention relates to an apparatus and a method for inspecting a surface defect of a mass-produced casting part having a complicated shape, and a database used for the inspection.

  The present invention uses, as a database, defect information obtained from past defect data associated with design information and shape information of an inspection object. Based on the defect information in this database, the scanning direction of the measuring instrument and the scanning pitch in a plurality of axial directions are independently controlled for each surface inspection site.

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

  The outline of the inspection using the apparatus will be described with reference to FIGS.

  FIG. 1 shows an outline of the surface inspection apparatus of the present embodiment.

  In the figure, a surface inspection apparatus includes a measuring machine 2 (measuring unit) for measuring the surface of a structure 1 (inspection object) to be inspected, a first axis scanning unit 3 for scanning the measuring machine 2, A second axis scanning unit 4 for scanning the machine 2 in a direction different from the first axis scanning unit, a scanning axis changing unit 5 for changing the scanning direction of the first axis scanning unit 3 and the second axis scanning unit 4, and design information Storage unit 6 that stores defect information associated with the inspection target shape obtained from the past inspection data, and processing unit 7 that sets scanning conditions from the defect information sent from first storage unit 6. A control unit 8 for controlling the measuring device 2, the first scanning unit 3, the second scanning unit 4, and the scanning axis changing unit 5 based on the scanning conditions set by the processing unit 7, and a measurement sent from the measuring device 2. A measurement result processing unit 9 for calculating the inspection result of the surface shape from the data; It includes a display unit 10 for displaying a second storage unit 11 for storing the results of the measurement result processing unit 9, a.

  The measuring device 2 is a laser distance meter. The measuring device 2 is moved by the first axis scanning unit 3 and the second axis scanning unit 4 to measure the distance between the measuring device 2 and the inspection object at each measurement point, thereby removing irregularities on the surface of the structure 1. Detect two-dimensionally. The defect detects not only the concave part but also the convex part. The laser irradiates in a direction perpendicular to the plane indicated by the dotted line in FIG.

  The movement of the measuring device 2 by the scanning unit is one-dimensional (linear), and the structure 1 is moved by, for example, moving in a direction orthogonal to the direction in which the measuring device 2 moves. The unevenness on the surface of the first surface may be detected two-dimensionally.

  Note that the measuring device 2 may be a camera that acquires an image of the surface of the structure 1. In this case, the unevenness on the surface of the structure 1 is detected based on the distribution of colors, color shading, discoloration, and the like in the image.

  In the figure, the processing unit 7 and the control unit 8 are described as separate constituent elements, but the present invention is not limited to this, and the control unit 8 is a part of the function of the processing unit 7. Alternatively, it may include all of them. In other words, the control unit 8 may have a function of setting a scanning condition from the defect information sent from the first storage unit 6. Further, the measuring device 2 may include some or all of the functions of the processing unit 7. Furthermore, the measuring device 2 or the control unit 8 may include some or all of the functions of the first axis scanning unit 3, the second axis scanning unit 4, and the scanning axis changing unit 5. Therefore, in the present invention, the case where the measuring device 2 or the control unit 8 includes the function of the processing unit 7 and the case where the processing unit 7 and the measuring device 2 or the control unit 8 are separate components are the same. It is regarded as an invention idea.

  Further, the measurement result processing unit 9 may be included in the control unit 8. The second storage unit 11 may also be included in the first storage unit 6.

  In summary, the devices that perform calculations, such as the processing unit 7, the control unit 8, and the measurement result processing unit 9, may be one electronic circuit. In the present specification, these are collectively referred to as a “control unit” or an “operation unit”. Further, devices that store and accumulate data, such as the first storage unit 6 and the second storage unit 11, are collectively referred to as “storage units” in this specification. The storage unit has a computer-readable database. The storage unit may be built in the surface inspection apparatus, or may be an external hard disk drive (HDD), an optical disk such as a DVD, a memory stick, an SD memory card, or another external memory.

  FIG. 2 is a flowchart illustrating the surface inspection method according to the present embodiment. In the following description, reference numerals of the surface inspection apparatus in FIG. 1 are also used.

  FIG. 2 shows an inspection process for one inspection object.

  When the inspection is started in the inspection start step S101, in the defect information reading step S102, the shape-specific defect information 103 corresponding to the shape of the structure 1 to be inspected is read from the first storage unit 6, and the processing unit 7 Sent to Then, in the scanning condition setting step S104, the scanning condition is set by the processing unit 7, and in the shape measurement step S105, the control unit 8 controls the measuring device 2, the first scanning unit 3, the second scanning unit 3 based on the set scanning condition. The scanning unit 4 and the scanning axis changing unit 5 are controlled, and the shape measurement according to the defect information of the structure 1 is performed.

  After that, the shape measurement data 106 is sent from the measuring device 2 to the measurement result processing section 9, and the shape is determined from the shape measurement data 106 in shape determination step S <b> 107. If it is determined to pass, the process proceeds to an inspection termination payout step S108, and if it is determined to be unsuccessful, the process proceeds to a database registration presence / absence determination step S109.

  In the database registration presence / absence determination step S109, it is determined whether the detected defect information has been registered in the first storage unit 6. If the detected defect information has already been registered, the process proceeds to a defective product unloading step S112. If it is determined that the registration has not been made, the process proceeds to the defect detail measurement step S110, and the detailed information of the detected defect is measured again. The measured defect information is sent to the first storage unit 6 as new defect information 111, and is reflected and stored in the shape-specific defect information 103. The inspection object after the determination proceeds to a defective product unloading step S112, and is discharged as a defective product.

  Hereinafter, details of each step of the inspection process and the scan setting calculation will be individually described.

  FIG. 3 is a diagram illustrating an example of defect information of the inspection object stored in the storage unit.

  First, details of the defect information stored in the first storage unit 6 of FIG. 1 and associated with the inspection target shape will be described with reference to FIG.

  In FIG. 3, the model number of the inspection object, the measurement direction of the inspection object, the location where the defect has occurred, the defect shape, and the defect information number are shown as defect information.

  Defects targeted by this device refer to shape changes that can determine the difference from a healthy part with a surface measuring device, and include dent defects such as scratches and dents and bulge defects such as burrs. Including both. In a casting to be inspected, for example, there is a case where a molten metal does not sufficiently flow by a casting pouring method and a defect appears in a specific portion. Such a defect that occurs in a specific portion is estimated in advance by a casting simulation technique or the like for each formed shape in advance. In addition, defect information for each modeled shape inspected in the past using the present inspection apparatus or other means, that is, the location and shape of the defect occurrence is stored.

  The defect information of the inspection object shown in FIG. 3 may be stored in a computer-readable database. The defect information includes a defect shape, a defect occurrence position, a defect size, and a defect directionality.

  The information obtained by the above method is, as shown in the defect information list 12 in FIG. 3, the model number of the inspection target shape, the inspection target shape data, the inspection target measurement surface direction, the defect occurrence location (defect occurrence position), the defect shape The data, the defect information number, and the like are stored in the first storage unit in an associated state. For example, when the main inspection is applied to the inspection of a machined product, it is possible to store defect information in a similar manner by replacing a case where a processing mark or a burr remains at a specific portion by a processing process. The same can be said for defects that occur in the manufacturing process, such as dents and scratches that occur during transportation.

  Next, with reference to FIGS. 4 and 5, a method for setting the scanning conditions shown in the scanning condition setting step S104 in FIG. 2 will be described. Here, FIG. 4 shows a defect having directionality. On the other hand, FIG. 5 shows a defect having no directionality. In this specification, such a direction is referred to as “defect direction”.

  In the scanning condition setting step S104, first, information on the shape to be inspected is input to the processing unit. As an input method, for example, a shape reading unit (not shown in FIG. 1) may be provided to read the entire shape of the inspection object installed in the inspection device, or a method of reading information such as a model number stamp of the inspection object. Further, the shape list may be read in advance in accordance with the inspection plan, or information may be individually input by a person. The input inspection target shape is compared with the defect information list 12 stored in the first storage unit 6, and the defect information for each inspection target shape is read.

  An example of a method of determining the scanning axis direction and the scanning pitch for each part from the read defect information will be described with reference to FIG.

  FIG. 4 shows an example of the read defect shape.

  In setting the scanning conditions, first, a minimum ellipse circumscribing the defect area is obtained. The major axis of the ellipse is a, the minor axis is b, and the inclination of the major axis from the reference orthogonal axis is θ. The reference orthogonal axis at this time may be any axis. In FIG. 4, the inclination from the x-axis is represented by θ. Here, a and b are referred to as “defect size”. The method of displaying the defect size (the size of the defect) is not limited to this.

  Next, the direction of the scanning axis (scanning axis changing direction) of the scanning axis changing unit 5 is determined based on θ. Here, for example, settings are made such that the scanning axis changing unit 5 is rotated by θ from the reference direction so that the major axis a direction is parallel to the first axis scanning direction.

  Next, the first axis scanning pitch of the first axis scanning unit 3 is determined based on the size of the major axis a. Here, for example, a setting is made such that the first axis scanning pitch is less than half a / 2 of the major axis a so that the number of measurement points is always two or more with respect to the major axis a. Finally, the second axis scanning pitch of the second scanning unit 4 is determined from the size of the minor axis b. Here, for example, a setting is made such that the second axis scanning pitch is set to less than b / 2, which is half of the minor axis b, so that the number of measurement points is always two or more with respect to the minor axis b. Note that the method described here is merely an example, and the method is not limited to this, as long as a measurement point sufficient for detecting a defect can be set. For example, as a method of determining a scanning pitch for a defect having a small directivity as shown in FIG. 5, a ratio between a major axis a and a minor axis b is obtained. The determination may be made without controlling the scanning direction, and the scanning pitches of the two axes may be set to the same value. For example, when a / b <2, the scanning direction may not be changed, and both the first axis scanning pitch and the second axis scanning pitch may be set to be less than b / 2.

  Further, in the present embodiment, the method of obtaining the minimum circumscribed ellipse by fitting has been described. However, any other method may be used as long as the method can set the scanning axis direction and the scanning pitch of two different axes so as not to miss the defect. . Further, in the method of finding by fitting the minimum circumscribed ellipse, the first axis scanning direction and the second axis scanning direction are orthogonal to each other, but the scanning axis does not need to be orthogonal, and measurement points can be set so as not to miss a defect. The method is not limited to this.

  According to the above method, the scanning axis change direction, the first axis scanning pitch, and the second axis scanning pitch set by the processing unit 7 are associated with the defect occurrence location for each defect shape, and are set as the scanning conditions of the entire inspection target shape. It is set and sent to the control unit 8.

  Next, the measuring method shown in the shape measuring step S105 in FIG. 2 will be described with reference to FIGS.

  FIG. 6 is a diagram for explaining an example of scanning control based on scanning conditions set for a defect having directivity.

  FIG. 7 is a diagram illustrating measurement points when scanning a directional defect.

  FIG. 8 is a diagram for explaining an example of scanning control based on scanning conditions set for a defect having no directionality.

  FIG. 9 is a diagram showing measurement points when a defect having no directionality is scanned.

  The control unit 8 transmits a signal for operating the measuring device 2, the first scanning unit 3, the second scanning unit 4, and the scanning axis changing unit 5 based on the scanning conditions sent from the processing unit 7. At this time, in the scanning of the surface location corresponding to the defect occurrence location, as shown in FIG. 6, the rotation direction of the scanning axis changing unit 5, the scanning pitch of the first scanning unit 3, and the scanning pitch of the second scanning unit 4 are changed. Is done. This example shows a case where the scanning axis changing unit 5 is rotated by θ, the scanning pitch of the first scanning unit 3 is a / 2, and the scanning pitch of the second scanning unit 4 is b / 2.

  When scanning is performed with this setting on the defect surface having directivity shown in FIG. 4, for example, as shown in FIG. 7, at least two points in the defect area become measurement points, and the defect can be detected. In the measurement of a defect having a small directivity as shown in FIG. 5, the scanning direction by the scanning axis changing unit 5 is not controlled, and the first scanning unit 3 and the second scanning unit 4 are not controlled as shown in FIG. The scanning pitch may be set to the same value. This example shows a case where the scanning pitch of each of the two axes is b / 2.

  When scanning is performed on the defect shown in FIG. 5 with this setting, for example, as shown in FIG. 9, at least two points in the defect area become measurement points, and the defect can be detected. By the above method, the shape measurement data 106 is obtained by the measuring device 2 scanned under the conditions determined by the defect shape.

  The shape measurement data 106 measured in the shape measurement step S105 is sent to the shape determination step S107, and the measurement result processing unit 9 determines whether the shape is acceptable. The pass / fail judgment of the shape is performed, for example, by comparing shape data extracted from design information and the like with the shape measurement data 106, and if the partial shape deviation is within a predetermined value, it passes, and if it exceeds a predetermined value, it rejects. Make a decision. The method of determining the shape is not limited to this, and may be any determination method according to the purpose, such as determining local displacement or local curvature of the shape measurement data 106 and determining that the measured value exceeds a predetermined value, such as rejection. .

  For the inspection object determined to be rejected in the shape determination step S107, the flow proceeds to the database registration presence / absence determination step S109, and the detected defect information is stored in the defect information list 12 already stored in the first storage unit 6. It is determined whether it is included. The determination is made based on whether one or both of the defect occurrence location and the defect shape of the detected defect matches the defect information included in the defect information list 12.

  If the determinations match, it is determined that the detected defect is similar to the already stored defect information, and the process proceeds to the defective product unloading step S112 without adding new defect information.

  If the determinations do not match, it is determined that the detected defect is not stored, and the process proceeds to the detailed defect measurement step S110 in order to newly add defect information. In the defect detail measurement step S110, in order to specify the location and shape of the newly detected defect in detail, for example, the scanning pitch of the first axis scanning unit 3 and the second axis scanning unit 4 is minimized to determine the defect detection location. Measure around. Here, when the location and shape of the newly detected defect can be estimated, the scanning pitch of the first axis scanning unit 3, the scanning pitch of the second axis scanning unit 4, and the scanning axis changing unit are adjusted according to the shape. 5 may be controlled. Further, the scanning pitch may be appropriately increased in accordance with the estimated shape of the detected defect.

  The defect shape detected by the above method is sent to the first storage unit 6 as new defect information 111, and is added to the defect information list 12. Inspection is performed using the updated defect information list 12 from the inspection of the inspection object to be transmitted next.

  According to the above-described method, in the surface inspection of a structure in which a different defect occurs for each part, a highly reliable inspection without overlooking the defect can be performed at a higher speed.

  In the present embodiment, as shown in FIG. 1, the measurement range of the measuring device 2 is a point, and scanning is performed by the first scanning unit 3 and the second scanning unit 4, and the surface of the structure 1 is two-dimensionally scanned. Although an example of measuring an area has been described, the present invention is not limited to this.

  For example, as shown in FIG. 10, the measuring device 2 has a linear measurement range. Here, the laser is irradiated linearly. The first scanning unit 3 may scan in a direction different from the linear measurement range to measure a two-dimensional area on the surface of the structure 1. At this time, the scanning pitch of the linear measurement range, which is the first scanning axis, is changed by an internal setting of the measuring device 2, for example, the measurement magnification, and the scanning pitch of the second scanning axis is changed by the first scanning unit 3. I do.

  Further, as shown in FIG. 11, the measuring device 2 may be provided on a robot arm 13 having three-dimensional degrees of freedom. The robot arm 13 is used for moving the measuring device 2. At this time, the scanning direction is determined by setting the scanning path of the robot arm 13, and the scanning pitch is determined by the scanning speed of the robot arm 13. Further, three or more scanning units may be provided to set more scanning axes. In addition, the control of the scanning pitch of the scanning unit may be limited to, for example, only one direction, without setting all axes to be controlled according to the detection defect target.

  1: structure, 2: measuring instrument, 3: first axis scanning section, 4: second axis scanning section, 5: scanning axis changing section, 6: first storage section, 7: processing section, 8: control section, 9: measurement result processing unit, 10: display unit, 11: second storage unit, 12: defect information list, 13: robot arm, 103: defect information by shape, 106: shape measurement data, 111: new defect information, S101 : Inspection start step, S102: defect information reading step, S104: scanning condition setting step, S105: shape measurement step, S107: shape determination step, S108: inspection end payout step, S109: database registration presence / absence determination step, S110: defect details Measuring step, S112: defective product unloading step.

Claims (26)

An apparatus for inspecting the surface of an inspection object,
A measuring unit and a control unit,
The measurement unit is movable by a command from the control unit,
Setting scanning conditions using the defect information of the inspection object ,
A function of setting measurement points at a predetermined scanning pitch along one scanning axis;
A surface inspection apparatus having a function of setting measurement points at a predetermined scanning pitch along another scanning axis different from the scanning axis . It has a function of changing the direction of the scan axis, a surface inspection apparatus according to claim 1. Moreover, with a storage unit for storing the defect information, the surface inspection apparatus according to claim 1 or 2. The defect information includes defect shape, defect location, including defect size and defect orientation, surface inspection apparatus according to any one of claims 1-3. The surface inspection apparatus according to claim 4 , wherein the scanning condition is set based on the defect information for each of the plurality of defects having different defect occurrence positions. Based on the defect position, sets a scanning range of the measuring portion, the surface inspection apparatus according to claim 4 or 5. The surface inspection apparatus according to any one of claims 4 to 6 , wherein a scanning pitch of the measurement unit is set based on the defect size. Based on the defect directional, to set the direction of the scan axis, a surface inspection apparatus according to any one of claims 4-7. The surface inspection apparatus according to claim 8 , wherein the scanning axis is set to be along a longitudinal direction of the defect. The surface inspection apparatus according to claim 9 , wherein a scanning pitch in the scanning axis along the longitudinal direction is longer than a scanning pitch in another scanning axis. A scan pitch in the scan axis along the longitudinal direction is set so that the measurement unit has at least one measurement point in a range of the length of the defect in the longitudinal direction, and the other scan axis The surface inspection apparatus according to claim 10 , wherein the scanning pitch is set so that the measurement unit has at least one measurement point within a range of a length of the defect in a direction of the another scanning axis. The surface inspection apparatus according to any one of claims 1 to 11 , wherein when a defect not included in the defect information is detected, defect information of the defect is acquired. A method for inspecting the surface of an inspection object,
Setting a scanning condition using the defect information of the inspection object,
Performing a shape measurement in accordance with the defect information based on the scanning conditions;
Setting measurement points at a predetermined scanning pitch along one scanning axis;
Setting a measurement point at a predetermined scanning pitch along another scanning axis different from the scanning axis . 14. The surface inspection method according to claim 13 , further comprising a step of changing a direction of the scanning axis. The surface inspection method according to claim 13 , further comprising reading the defect information before setting the scanning condition. The surface inspection method according to any one of claims 13 to 15 , wherein the defect information includes a defect shape, a defect occurrence position, a defect size, and a defect direction. 17. The surface inspection method according to claim 16 , further comprising the step of, for a plurality of defects having different defect occurrence positions, setting the scanning condition based on the defect information for each of the defect occurrence positions. Furthermore, on the basis of the defect position, comprising the step of setting a scanning range of the shape measurement, surface inspection method according to claim 16 or 17. Furthermore, based on the defect size, before including the step of setting the Kihashi査pitch, surface inspection method according to any one of claims 16-18. Furthermore, on the basis of the defect orientation, comprising the step of setting the direction of the scan axis, the surface inspection method according to any one of claims 16-19. 21. The surface inspection method according to claim 20 , further comprising the step of setting the scanning axis so as to be along the longitudinal direction of the defect. 22. The surface inspection method according to claim 21 , wherein a scanning pitch in the scanning axis along the longitudinal direction is longer than a scanning pitch in another scanning axis. Further, in the scanning pitch in the scan axis along the longitudinal direction and set to have a measurement point of at least one point in the longitudinal direction of the length range of the previous SL defects, and the another scan axis the scanning pitch, before Symbol comprising the step of setting to have a measurement point of at least one point in the direction of the length range of the another scan axis of the defect, the surface inspection method according to claim 22, wherein. The surface inspection method according to any one of claims 13 to 23 , wherein when a defect not included in the defect information is detected, defect information of the defect is obtained. A measuring unit, and a control unit, wherein the measuring unit is movable by a command of the control unit, and sets a scanning condition using defect information of the inspection object. A surface inspection device having a function of setting measurement points at a predetermined scanning pitch along with a function of setting measurement points at a predetermined scanning pitch along another scanning axis different from the scanning axis. storing Kiketsu Recessed information before use in performing the inspection of the surface of the inspection object, a computer-readable database. 26. The computer-readable database according to claim 25 , wherein the defect information includes a defect shape, a defect occurrence position, a defect size, and a defect direction.

Images