JP2018044873A - Surface inspection apparatus, surface inspection method, and database - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface inspection apparatus capable of carrying out accurately surface inspection of inspection object at high speed.SOLUTION: The surface inspection apparatus is an apparatus for inspecting the surface of the inspection object 1, which includes a measurement part 2 and a control unit 8. The measurement part is movable via a command from the control unit. A scan direction of the measurement part for each surface inspection part and the scan pitch in plural axial directions are independently controlled on the basis of a piece of design information of the inspection object and defects information stored in a first storage part 6 which are obtained previous defect data being associated with shape information.SELECTED DRAWING: Figure 1

Description

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

  In the mass production site of cast parts, it is necessary to determine the presence or absence of defects after the casting process and provide it to the next machining process. In the casting process, defects of various shapes can occur both inside and outside due to various factors. In particular, a hot water defect generated on the surface of a component may become 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 end of the casting process and to judge the quality of the part.

  In the conventional inspection process, a manual visual inspection is mainly performed. However, it is inefficient to visually inspect all mass-produced products in large quantities, and there is a high risk of oversight. Thus, there is an increasing need for automatic defect inspection technology that can replace visual inspection.

  For automatic inspection, in-line automatic inspection for planar objects such as electronic boards, as well as devices that efficiently inspect relatively large-sized objects and objects with complex shapes, such as automobile body panels Various proposals have been made.

  For example, Patent Document 1 relates to a technique for inspecting a surface of an object having a curved surface, and selects a scanning direction and a scanning speed of an optical sensor based on a cross-sectional curvature of a work to be inspected and a length of the work, Describes a method and an apparatus for selecting a scanning pattern on the basis of the height of the stepped surface portion and the preset shape data of the workpiece and inspecting surface defects.

Japanese Patent No. 4670180

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

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

  Therefore, the present invention has been made in view of such circumstances, and an object thereof is to perform surface inspection of an inspection object at high speed and with 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 according to a command from the control unit. The apparatus sets scanning conditions using 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. In addition, according to the present invention, since attention is paid to defect information of an inspection object, measurement of a non-defect portion can be omitted, and inspection can be performed at high speed.

It is a figure which shows roughly the whole structure of the surface inspection apparatus of this invention with the structure to be examined. It is a flowchart which shows the surface inspection method of this invention. It is a figure which shows the example of the defect information stored in the memory | storage part. It is a figure for demonstrating an example of the setting method of the scanning condition with respect to the defect which has directionality. It is a figure for demonstrating an example of the setting method of the scanning condition with respect to the defect which does not have directionality. It is a figure for demonstrating an example of the scanning control based on the scanning conditions set with respect to the defect which has directionality. It is a figure which shows the measurement point in the case of scanning the defect with directionality. It is a figure for demonstrating an example of the scanning control based on the scanning conditions set with respect to the defect which does not have directionality. It is a figure which shows the measurement point in the case of scanning the defect which does not have directionality. It is a figure which shows roughly the whole structure of the surface inspection apparatus of this invention using the measuring machine with a linear measurement range with the structure to be examined. It is a figure which shows roughly the whole structure of the surface inspection apparatus of this invention using a robot arm with the structure to be examined.

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

  The present invention uses defect information obtained from design information of inspection objects and past defect data associated with shape information as a database. Based on the defect information in the database, the scanning direction of the measuring machine and the scanning pitch in the multi-axis direction 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 this embodiment.

  In this figure, the surface inspection apparatus includes a measuring machine 2 (measuring unit) that measures the surface of a structure 1 (inspecting object) to be inspected, a first axis scanning unit 3 that scans the measuring machine 2, and a measurement. A second axis scanning unit 4 that scans the machine 2 in a direction different from the first axis scanning unit, a scanning axis changing unit 5 that changes the scanning direction of the first axis scanning unit 3 and the second axis scanning unit 4, and design information And a first storage unit 6 that stores defect information associated with an inspection target shape obtained from past inspection data, and a processing unit 7 that sets scanning conditions from the defect information sent from the first storage unit 6. And a control unit 8 that controls the measuring machine 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 machine 2. The measurement result processing unit 9 for calculating the inspection result of the surface shape from the data and the result of the measurement result processing unit 9 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 machine 2 is a laser distance meter. The measuring machine 2 is moved by the first axis scanning unit 3 and the second axis scanning unit 4 to measure the distance between the measuring machine 2 and the inspection object at each measurement point, thereby forming irregularities on the surface of the structure 1. Two-dimensional detection. A defect detects not only a recessed part but a convex part. The laser irradiates in a direction orthogonal to the plane indicated by the dotted line in this figure.

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

  The measuring device 2 may be a camera that acquires an image of the surface of the structure 1. In this case, irregularities on the surface of the structure 1 are detected based on color distribution, 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 components, 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. Or it is good also as what includes all. In other words, the control unit 8 may have a function of setting scanning conditions from defect information sent from the first storage unit 6. The measuring device 2 may include a part or all of the functions of the processing unit 7. Further, the measuring instrument 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 is the same as the case where the processing unit 7 and the measuring device 2 or the control unit 8 are separate components. This is considered as an inventive 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, a device that performs calculations, such as the processing unit 7, the control unit 8, and the measurement result processing unit 9, may be a single electronic circuit. In this specification, these are collectively referred to as “control unit” or “calculation unit”. In addition, devices such as the first storage unit 6 and the second storage unit 11 that store and store data are collectively referred to as “storage unit” 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 other external memory.

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

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

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

  Thereafter, the shape measurement data 106 is sent from the measuring machine 2 to the measurement result processing unit 9, and whether the shape is acceptable or not is determined from the shape measurement data 106 in the shape determination step S 107. If it is determined to be acceptable, the process proceeds to inspection completion payout step S108, and if it is determined to be unacceptable, the process proceeds to database registration presence / absence determination step S109.

  In the database registration presence / absence determination step S109, it is determined whether or not the detected defect information is registered in the first storage unit 6. If registration has already been performed, the process proceeds to a defective product carrying out step S112. If it is determined that it has not been registered, the process proceeds to 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 defect information 103 by shape. The object to be inspected after the determination proceeds to a defective product carrying out step S112 and is carried out 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 defect information associated with the shape to be inspected stored in the first storage unit 6 of FIG. 1 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 defect occurrence location, the defect shape, and the defect information number are shown as defect information.

  Defects targeted by this device refer to changes in shape that can be determined by a surface measuring machine to be different from sound parts, such as dent-shaped defects such as scratches and dents, and bulge-shaped defects such as burrs. Including both. There is a case in which a defect appears in a specific part in a cast product to be inspected, for example, due to a casting pouring method in which the molten metal does not flow sufficiently. A defect occurring in such a specific part is estimated in advance for each modeling shape by a casting simulation technique or the like. Further, defect information for each modeling shape inspected in the past by using this inspection apparatus or other means, that is, a defect occurrence location or shape is accumulated.

  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 includes 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, as in the defect information list 12 of FIG. Data, defect information numbers, and the like are stored in the first storage unit in an associated state. For example, when this inspection is applied to machining product inspection, defect information can be similarly stored by replacing with a case in which a processing mark or a burr remains in a specific part by a processing process. The same applies to defects that occur in the manufacturing process, such as dents and scratches that occur during conveyance.

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

  In the scanning condition setting step S104, information on the shape to be inspected is first 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 apparatus, or a method of reading information such as a model number stamp of the inspection object. Further, a shape list may be read in advance according to the inspection plan, or a person may input information individually. The input inspection target shape is compared with the defect information list 12 stored in the first storage unit 6, and defect information for each inspection target shape is read out.

  An example of a method for 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 from the reference orthogonal axis in the major axis direction is θ. The reference orthogonal axis at this time may be any axis. In FIG. 4, the inclination from the x-axis is θ. Here, a and b are referred to as “defect size”. In addition, the display method of a defect size (defect dimension) is not limited to this.

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

  Next, the first axis scanning pitch of the first axis scanning unit 3 is determined from the size of the major axis a. Here, for example, the first axis scanning pitch is set to be less than a / 2, which is half of the major axis a, so that there are always two or more measurement points 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, the second axis scanning pitch is set to be less than b / 2, which is half of the minor axis b, so that there are always two or more measurement points with respect to the minor axis b. Note that the method described here is merely an example, and is not limited to this as long as it is a method capable of setting a measurement point sufficient for detecting a defect. For example, as a method for determining a scanning pitch for a defect having a small directionality as shown in FIG. 5, the ratio of the major axis a to the minor axis b is obtained, and if the defect is greater than a certain threshold, the defect has no directionality. By determining, the scanning direction may not be controlled, and the biaxial scanning pitch 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.

  In the present embodiment, the method of obtaining the circumscribed minimum ellipse has been described. However, any other method may be used as long as it can set a scanning axis direction that does not miss a defect and a scanning pitch of two different axes. . Furthermore, in the method of obtaining by fitting the circumscribed minimum ellipse, the first axis scanning direction and the second axis scanning direction are orthogonal to each other, but the scanning axes are not necessarily orthogonal, and the measurement points can be set so as not to overlook defects. If it is a method, it will not be restricted to this.

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

  Next, the measurement method shown in the shape measurement 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 directionality.

  FIG. 7 is a diagram illustrating measurement points when a defect having directionality is scanned.

  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 illustrating measurement points when a defect having no directionality is scanned.

  The control unit 8 transmits a signal for operating the measuring instrument 2, the first scanning unit 3, the second scanning unit 4, and the scanning axis changing unit 5 based on the scanning condition sent from the processing unit 7. At this time, in the scanning of the surface portion corresponding to the defect occurrence portion, 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 as shown in FIG. Is done. In this example, 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 a defect surface having directivity shown in FIG. 4, for example, as shown in FIG. 7, at least two points in the defect region become measurement points, and the defect can be detected. Further, in the measurement for a defect having a small directivity as shown in FIG. 5, the scanning direction by the scanning axis changing unit 5 is not controlled as shown in FIG. The scanning pitch may be set to the same value. In this example, a case where the biaxial scanning pitch is b / 2 is shown.

  If the defect shown in FIG. 5 is scanned 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. According to the above method, the shape measurement data 106 is obtained by the measuring machine 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 or not the shape is acceptable. The pass / fail judgment of the shape, for example, compares the shape data extracted from the design information and the like with the shape measurement data 106, and passes if the partial shape deviation is within a predetermined value, fails if it exceeds the predetermined value, etc. Make a decision. The shape determination method is not limited to this. For example, a local displacement or a local curvature of the shape measurement data 106 may be obtained, and an arbitrary determination method may be used according to the purpose, such as determination that the shape measurement data 106 exceeds a predetermined value. .

  For the inspected object determined to be unacceptable in the shape determination step S107, the flow proceeds to the database registration presence determination step S109, and the detected defect information is already stored in the first storage unit 6 in the defect information list 12. 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 advances to defective product carrying out step S112 without newly adding defect information.

  If the determinations do not match, it is determined that the detected defect is not stored, and the defect information is newly added, and the process proceeds to the defect detail measurement step S110. In the defect detail measurement step S110, in order to specify in detail the location and shape of the newly detected defect, for example, the defect detection location is minimized by minimizing the scanning pitch of the first axis scanning unit 3 and the second axis scanning unit 4. Measure around the area. Here, when the newly detected defect occurrence position and shape 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 matched to the shape. 5 scanning directions 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 added to the defect information list 12. The inspection is performed using the updated defect information list 12 from the inspection of the inspection target to be sent next.

  According to the above method, in the surface inspection of a structure in which a different defect occurs in each part, it is possible to perform a highly reliable inspection without missing a defect at a higher speed.

  In this embodiment, as shown in FIG. 1, the measuring range of the measuring instrument 2 is a point, scanned by the first scanning unit 3 and the second scanning unit 4, and two-dimensional with respect to the surface of the structure 1. Although the example which measures an area | region was demonstrated, this invention is not limited to this.

  For example, as shown in FIG. 10, the measuring instrument 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 region with respect to the surface of the structure 1. At this time, the scanning pitch of the linear measuring range which is the first scanning axis is changed by the internal setting of the measuring instrument 2, for example, the measurement magnification, and the scanning pitch of the second scanning axis is changed by the first scanning unit 3. To do.

  Further, as shown in FIG. 11, the measuring device 2 may be provided on a robot arm 13 having a three-dimensional degree 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. Furthermore, more scanning axes may be set by providing three or more scanning units for the scanning axes. In addition, regarding the control of the scanning pitch of the scanning unit, the axis to be controlled according to the detection defect target may not be all the scanning units, and may be limited to only one direction, for example.

  1: structure, 2: measuring machine, 3: first axis scanning unit, 4: second axis scanning unit, 5: scanning axis changing unit, 6: first storage unit, 7: processing unit, 8: control unit, 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 Measurement step, S112: Defective product removal step.

Claims (30)

An apparatus for inspecting the surface of an inspection object,
A measurement unit and a control unit,
The measuring unit is movable by a command from the control unit,
A surface inspection apparatus that sets scanning conditions using defect information of the inspection object.   The surface inspection apparatus according to claim 1, which has a function of setting measurement points at a predetermined scanning pitch along one scanning axis.   The surface inspection apparatus according to claim 2, having a function of changing a direction of the scanning axis.   The surface inspection apparatus according to claim 2, further comprising a function of setting measurement points at a predetermined scanning pitch along another scanning axis different from the scanning axis.   Furthermore, the surface inspection apparatus as described in any one of Claims 1-4 provided with the memory | storage part which stores the said defect information.   The surface inspection apparatus according to claim 1, wherein the defect information includes a defect shape, a defect occurrence position, a defect size, and a defect directionality.   The surface inspection apparatus according to claim 6, wherein the scanning condition is set based on the defect information for each of the defect occurrence positions for a plurality of defects having different defect occurrence positions.   The surface inspection apparatus according to claim 6, wherein a scanning range of the measurement unit is set based on the defect occurrence position.   The surface inspection apparatus according to claim 6, wherein a scanning pitch of the measurement unit is set based on the defect size.   The surface inspection apparatus according to claim 6, wherein a direction of the scanning axis is set based on the defect directionality.   The surface inspection apparatus according to claim 10, wherein the scanning axis is set along the longitudinal direction of the defect.   The surface inspection apparatus according to claim 11, wherein a scanning pitch on the scanning axis along the longitudinal direction is longer than a scanning pitch on another scanning axis.   The scanning pitch on the scanning axis along the longitudinal direction is set so that the measuring unit has at least one measuring point in the longitudinal length range of the defect, and the other scanning axis The surface inspection apparatus according to claim 12, wherein the scanning pitch is set so that the measurement unit has at least one measurement point in a range of the length of the defect in the direction of the other scanning axis.   The surface inspection apparatus according to claim 1, wherein defect information of the defect is acquired when a defect not included in the defect information is detected. A method for inspecting the surface of an inspection object,
Setting scanning conditions using defect information of the inspection object;
Measuring the shape of the inspection object based on the scanning condition.   The surface inspection method according to claim 15, further comprising the step of setting measurement points at a predetermined scanning pitch along one scanning axis.   The surface inspection method according to claim 16, further comprising a step of changing a direction of the scanning axis.   The surface inspection method according to claim 16, further comprising a step of setting measurement points at a predetermined scanning pitch along another scanning axis different from the scanning axis.   Furthermore, the surface inspection method as described in any one of Claims 15-18 including the process of reading the said defect information, before setting the said scanning conditions.   20. The surface inspection method according to claim 15, wherein the defect information includes a defect shape, a defect occurrence position, a defect size, and a defect directionality.   21. The surface inspection method according to claim 20, further comprising a step of setting the scanning condition based on the defect information for each of the plurality of defects having different defect occurrence positions.   Furthermore, the surface inspection method of Claim 20 or 21 including the process of setting the scanning range of the said measurement part based on the said defect generation position.   Furthermore, the surface inspection method as described in any one of Claims 20-22 including the process of setting the scanning pitch of the said measurement part based on the said defect size.   Furthermore, the surface inspection method as described in any one of Claims 20-23 including the process of setting the direction of the said scanning axis based on the said defect directionality.   25. The surface inspection method according to claim 24, further comprising a step of setting the scanning axis along the longitudinal direction of the defect.   26. The surface inspection method according to claim 25, wherein a scanning pitch on the scanning axis along the longitudinal direction is longer than a scanning pitch on another scanning axis.   Further, the scanning pitch on the scanning axis along the longitudinal direction is set so that the measuring unit has at least one measuring point in the longitudinal length range of the defect, and the another 27. The surface according to claim 26, comprising the step of setting a scanning pitch in a scanning axis so that the measuring unit has at least one measuring point in a range of a length of the defect in the direction of the other scanning axis. Inspection method.   The surface inspection method according to any one of claims 15 to 27, wherein when a defect not included in the defect information is detected, defect information of the defect is acquired.   A computer-readable database storing defect information of the inspection object used when inspecting the surface of the inspection object.   30. The computer readable database of claim 29, wherein the defect information includes a defect shape, a defect occurrence position, a defect size, and a defect directionality.

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