JP2019049509A - Surface inspection device and surface inspection method - Google Patents

Abstract

To provide a surface inspection device and surface inspection method that automatically and correctly as well as quickly measure a surface shape of a measurement object of mass-production casting products to determine presence or absence of defects.SOLUTION: A surface inspection device comprises: an optical measuring instrument 2; movement parts 3 and 5 that move a measurement object 1 nd the optical measuring instrument 2; a rotary stage 4 that causes the measurement object 1 to rotate; a control unit 6; and a processing unit 8. Let a measurement condition be a condition that the control unit 6 controls the movement parts 3 and 5 and the rotary stage 4, and let a condition determination index be an index for determining a measurement condition of a main measurement to be conducted with respect to many measurement objects 1. The processing unit 8 is configured to: input a plurality of sets of measurement conditions; obtain a measurement area of the measurement object 1 with respect to the measurement condition of each set, using a measurement result with respect to a small number of measurement objects 1 by the optical measuring instrument 2 under the measurement condition of each set; and determine the measurement condition for each number of measurements, using the condition determination index and the measurement area with respect to the measurement condition of each set. The optical measuring instrument 2 is configured to, when the control unit 6 controls the movement parts 3 and 5, and the rotary stage 4 according to the measurement condition for each number of measurements, conduct the main measurement.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface inspection apparatus and a surface inspection method, and more particularly to a surface inspection apparatus and a surface inspection method for mass-produced products.

  In the casting process of mass-produced castings such as automobile parts, before conducting the next machining process, visual inspection is performed to confirm that there are no defects such as scratches, dents, burrs, and defects due to mold loss. carry out. As the production rate of cast products increases and production speed increases, it is difficult to confirm by visual inspection, so there is a need for an automatic visual inspection technique that replaces visual inspection. Many mass-produced cast products such as automobile parts have complicated three-dimensional shapes, so for measurement objects having such complicated shapes, measurement can be performed with high accuracy to measure the shape and determine the presence or absence of defects A device is needed.

  In Patent Document 1, the direction in which the optical probe and the object to be measured are relatively moved is determined based on the position information of the measurement area calculated based on the image data obtained from the optical probe, and based on this movement direction And a shape measuring device for controlling the moving mechanism. Patent Document 2 uses a reference data representing the shape of the inspection object to set a path along which the relative position of the three-dimensional shape sensor that irradiates the laser to the inspection object passes at the time of inspection. A shape inspection device is disclosed that controls the relative position.

JP 2014-145735 Unexamined-Japanese-Patent No. 2014-169947

  The shape measuring device described in Patent Document 1 can measure the shape of the measurement object having a complicated shape with high accuracy regardless of the shape and the surface state of the measurement object. However, when measuring the entire surface of the measurement object, when the relative position of the optical probe and the measurement object is changed and measurement is performed multiple times, there are many areas that are measured redundantly between different measurement times. There is a problem that the inspection is concerned about being inefficient.

  In the shape inspection apparatus described in Patent Document 2, the route of the three-dimensional shape sensor is determined using the reference data representing the shape of the inspection object, but the surface state of the measurement object is not considered. When the measurement object is a mass-produced cast product, unevenness on the surface of the measurement object varies depending on the individual, and reflected light from the measurement object is not detected on the surface where the incident angle of the laser light is large. There is. For this reason, depending on the individual of the measurement object, there is a problem that the shape can not be acquired at the location where the data loss occurs, and there is a possibility that the defect may be overlooked.

  The present invention has been made in view of the above problems, and a surface inspection apparatus and a surface inspection method for determining the presence or absence of a defect by automatically measuring the surface shape of a measurement object which is a mass-produced cast product accurately and rapidly. Intended to provide.

  The surface inspection apparatus according to the present invention comprises an optical measuring device that measures the surface shapes of a plurality of measurement objects having a three-dimensional shape, a moving unit that moves the measurement object and the optical measurement device relative to each other, and It has a rotation stage which rotationally moves a measurement object, a control unit which controls the moving unit and the rotation stage, and a processing unit which controls the control unit and the optical measuring instrument. The measurement condition is a condition under which the control unit controls the moving unit and the rotation stage, and the preliminary measurement is performed with respect to the measurement object of which the optical measuring device is a part of the measurement object The measurement is performed, and the main measurement is performed by the optical measurement machine on at least the remaining number of the measurement objects, and the condition determination index is the measurement condition to be used for the main measurement. As an indicator to The processing unit inputs a plurality of sets of the measurement conditions, and using the results of the preliminary measurement performed by the optical measurement device under each set of the measurement conditions, the processing conditions are set to the respective set of the measurement conditions. The area to be measured of the object to be measured is determined, and using the condition determination index and the area to be measured for each set of measurement conditions, measurement is performed each time among a plurality of sets of measurement conditions. It is configured to determine the measurement condition of The optical measuring instrument is configured to perform the main measurement when the control unit controls the moving unit and the rotation stage according to the measurement condition for each measurement.

  According to the present invention, it is possible to provide a surface inspection apparatus and a surface inspection method for automatically and accurately and rapidly measuring the surface shape of a measurement object which is a mass-produced cast product to determine the presence or absence of a defect.

It is a figure which shows the structure of the surface inspection apparatus by Example 1 of this invention. It is a flowchart of the surface inspection method with respect to a measurement object which the surface inspection apparatus by Example 1 of this invention implements. It is a flowchart which shows the procedure of step S1 which calculates | requires the area | region which should be measured. It is explanatory drawing of measurement conditions. It is explanatory drawing of alignment with measurement data and shape data. It is explanatory drawing of the method of determining whether each lattice cell of shape data should measure. It is a figure which shows the identification number of the group of measurement conditions and the area | region which should be measured preserve | saved at a memory | storage part. It is a flowchart which shows the procedure of step S2 which determines the measurement conditions in each measurement time. It is a figure which shows the structure of the surface inspection apparatus by Example 2 of this invention. It is a flowchart which shows the procedure of step S2 which the surface inspection apparatus by Example 2 of this invention performs.

  The surface inspection apparatus and the surface inspection method according to the present invention specify the measurement conditions for measuring (performing the main measurement) the surface shapes of a plurality of measurement objects having a three-dimensional shape, according to the condition determination index By determining for each measurement cycle in, it is possible to acquire data of the surface shape of the measurement object accurately and at high speed. The condition determination index is an index for determining the measurement condition used for the main measurement. The condition determination index includes, for example, the area of the area to be measured of the measurement object (the area where data on the surface shape can be obtained without defects) or the necessity (priority) of inspection for each part of the surface of the measurement object. It can be used. If the area of the area to be measured of the measurement object is used as the condition determination index as in the first embodiment of the present invention, the largest possible area of the measurement object can be measured. As in the second embodiment of the present invention, by using the priority for each portion of the surface of the measurement object as the condition determination index, it is possible to preferentially measure the portion where the necessity of inspection of the measurement object is high. .

  According to the present invention, while being able to inspect the measurement object of mass-produced object accurately in a short time, within the determined number of times of measurement (measurement time), the area as wide as possible and the part where the necessity of inspection is high It is possible to measure and understand the area that was not measured.

  Hereinafter, a surface inspection apparatus and a surface inspection method according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing the configuration of a surface inspection apparatus according to a first embodiment of the present invention. The surface inspection apparatus according to the present embodiment rotates a measurement object 2 for measuring the surface shapes of a plurality of measurement objects 1 having a three-dimensional shape, a robot arm 3 for moving the measurement device 2, and a measurement object 1 placed thereon. A rotation stage 4, a scanning unit 5 for moving the rotation stage 4 in one direction in parallel, a control unit 6, a storage unit 7, and a processing unit 8.

  The measuring device 2 is an optical measuring device such as a laser displacement meter, a camera or a projector. In the present embodiment, a laser displacement gauge is used as the measuring device 2. The measuring device 2 measures the surface shape of the measurement object 1 and acquires data of the surface shape of the measurement object 1.

  The rotation stage 4 rotationally moves the measurement object 1 by rotating, and changes the direction of the measurement object 1.

  The robot arm 3 and the scanning unit 5 are moving units that move the measurement object 1 and the measuring device 2 relative to each other.

  The control unit 6 gives operation commands to the robot arm 3, the rotation stage 4, and the scanning unit 5 to control them.

  The storage unit 7 stores information of an area where the measuring device 2 can acquire data of the surface shape of the measurement object 1 without loss (an area to be measured of the measurement object 1), together with the measurement conditions for that area. . The measurement conditions are conditions under which the control unit 6 controls the robot arm 3, the rotation stage 4, and the scanning unit 5.

  The processing unit 8 controls the control unit 6 and the measuring device 2. The processing unit 8 determines operations of the robot arm 3, the rotation stage 4, and the scanning unit 5 based on the information stored in the storage unit 7, and controls the control unit 6. In the present embodiment, the operations of the robot arm 3, the rotation stage 4 and the scanning unit 5 are the areas to be measured of the measurement object 1 (areas where surface shape data can be acquired without loss) by measurement with the specified number of measurements. Determine to increase the area of). The processing unit 8 also controls the measuring device 2 to cause the measuring device 2 to measure the measurement target 1.

  The measurement principle of the measuring device 2 (laser displacement gauge) will be described below. The measuring device 2 includes a light emitting unit that emits a laser beam (line laser 9) and a light receiving unit that receives the laser beam. When the measuring device 2 irradiates the measuring object 1 with the laser beam from the light emitting unit, the light reflected by the measuring object 1 is collected by the light receiving lens of the light receiving portion of the measuring device 2 and forms an image on the light receiving element Do. When the distance from the measuring device 2 to the measurement object 1 changes, the angle of the reflected light to be collected changes, and accordingly, the position at which the reflected light forms an image on the light receiving element changes. The amount of displacement of the imaging position on the light receiving element of this reflected light is proportional to the amount of change of the distance from the measuring device 2 to the measuring object 1, so the measuring device can be measured by reading the amount of displacement of the imaging position. The distance from 2 to the measurement object 1 can be measured.

  The position and angle of the measuring device 2 with respect to the measurement object 1 can be adjusted by the robot arm 3 and the scanning unit 5. The orientation of the measurement object 1 is adjusted by the rotation stage 4. The measuring unit 2 can scan the measurement target 1 with the laser beam as the scanning unit 5 translates the rotation stage 4 in parallel.

  The rotation stage 4 and the scanning unit 5 are not shown in FIG. 1, but an instrument for fixing the measurement object 1 so that the measurement object 1 does not move unintentionally during scanning, and the measurement object with the correct posture A sensor may be provided to confirm that the object 1 is installed. Further, although not shown in FIG. 1, the rotary stage 4 and the scanning unit 5 may be provided with a mechanism for holding the measurement target 1 and changing its posture.

  FIG. 2 is a flowchart of a surface inspection method for one type (the same shape and size as each other) of the measurement object 1 performed by the surface inspection apparatus according to the present embodiment.

In step S1, the measuring device 2 measures the surface shape of the measurement object 1 under a plurality of sets of measurement conditions to obtain an area to be measured for each set, and the storage unit 7 obtains information on the area to be measured. save. In step S2, the processing unit 8, based on information stored in the storage unit 7, determines the measurement condition i _k at each measurement times k for the specified number of measurements n. In step S3, the measurement conditions i _k determined in step S2, to measure the surface shape of the measurement object 1. In step S4, the presence or absence of a defect on the surface of the measurement object 1 is determined using the data obtained by the measurement in step S3.

  Step S1 is preferably performed on a part of the plurality of measurement objects 1 (a small number of samples). The measurement performed on a part of the plurality of measurement objects 1 is referred to as preliminary measurement. Steps S3 and S4 are sequentially performed on a large number of measurement objects 1 (mass-produced products). That is, in step S1, preliminary measurement is performed on a small number of measurement objects 1, and in step S3, main measurement is performed on a large number of measurement objects 1. The main measurement is a measurement performed on at least the remaining number of measurement objects 1 (that is, at least a large number of measurement objects 1 for which preliminary measurement has not been performed) among the measurement objects 1. The main measurement may be performed on all numbers of measurement objects 1. Preliminary measurement is performed to obtain measurement conditions for each measurement in the main measurement.

  The surface inspection apparatus used for inspection of mass-produced cast products is desired to be able to inspect a large number of measurement objects 1 accurately in a short time. In the surface inspection apparatus according to the present embodiment, measurement conditions are determined using a small number of measurement objects 1 in steps S1 and S2, and a large number of measurement objects 1 are measured under these measurement conditions in steps S3 and S4. The presence or absence of a defect on the surface of the measurement object 1 is determined. Therefore, the surface inspection apparatus according to the present embodiment can inspect a large number of measurement objects 1 accurately in a short time.

  Each step will be described in detail below.

  First, step S1 will be described. In step S1, an area to be measured is determined for each of a plurality of sets of measurement conditions.

  FIG. 3 is a flowchart showing the procedure of step S1. Step S1 has steps S101 to S105.

  In step S101, the inspector inputs one set of measurement conditions to the processing unit 8.

  FIG. 4 is an explanatory diagram of measurement conditions. In FIG. 4, the moving direction of the scanning unit 5 is the x direction, the direction perpendicular to the x direction in the horizontal plane is the y direction, and the vertical direction (the direction perpendicular to the x direction and the y direction) is the z direction. For one set of measurement conditions, for example, the position coordinates (x, y, z) of the robot arm 3, the rotation angle φ based on the z axis of the robot arm 3, and the x axis of the rotation stage 4 The rotation angle θ, the movement start position, the movement end position, and the movement speed of the scanning unit 5 are included. The position coordinates (x, y, z) of the robot arm 3 are position coordinates of a connection point between the robot arm 3 and the measuring device 2. The rotation angle φ based on the z axis of the robot arm 3 is the rotation angle from the z axis of the connection point between the robot arm 3 and the measuring device 2. These measurement conditions are input by the inspector according to the size and the shape of the measurement object 1 so that the entire shape of the measurement object 1 can be measured.

  In step S102, the processing unit 8 moves the measurement target 1 relative to the measurement device 2 and measures the surface shape of the measurement target 1 (performs preliminary measurement). This measurement is performed by the measuring device 2 according to one set of measurement conditions input in step S101. The measurement target 1 is installed on the rotation stage 4 by an inspector or a transfer robot not shown in FIG. The measuring device 2 scans the measurement object 1 with a laser beam, and acquires the coordinates of the surface of the measurement object 1 as measurement data. At the time of measurement, the position of the measurement object 1 may be fixed and the measuring machine 2 may be moved and scanned by the robot arm 3 or the position of the measuring machine 2 may be fixed and the measurement object 1 may be moved by the scanning unit 5 You may scan.

  The light receiving elements of the measuring device 2 are arranged at equal intervals along the direction of the line laser 9. Therefore, measurement data is acquired for coordinates of equally spaced positions along the direction of the line laser 9. The three-dimensional shape of the measurement object 1 can be acquired by moving the measuring device 2 in a direction substantially perpendicular to the direction of the line laser 9 and scanning.

  The trigger giving the timing of measurement occurs continuously inside the measuring device 2. The trigger may be generated by measuring the amount of movement of the scanning unit 5 using an encoder and applying a pulse signal according to the amount of movement from the outside of the measuring device 2. In the case where the moving speed of the scanning unit 5 is constant and the trigger interval is constant, measurement data can be acquired for coordinates at regular intervals in the scanning direction.

  In step S103, the processing unit 8 inputs the shape data of the measurement object 1, and aligns the measurement data and the shape data acquired in step S102. The measurement data is a point cloud indicating coordinates of the surface of the measurement object 1. The shape data is data indicating the three-dimensional shape of the measurement object 1 and includes the coordinates of the surface of the measurement object 1. The shape data is a set of a large number of grid cells representing the surface of the measurement object 1, and is extracted from the design information of the measurement object 1, or based on measurement data of a standard sample of the measurement object 1. Can be created by The shape and size of the grid cell of the shape data can be determined in accordance with the three-dimensional shape of the measurement object 1. The shape data includes the area of each grid cell. Each grid cell is assigned an identification number.

  FIG. 5 is an explanatory diagram of alignment of the measurement data 10 and the shape data 11. FIG. 5 shows measurement data 10 and shape data 11 before alignment on the left side, and measurement data 10 and shape data 11 after alignment on the right side.

  In this alignment, the measurement data 10 and the shape data 11 are arranged in the same coordinate system, and the distance between the object of the shape represented by the measurement data 10 and the object of the shape represented by the shape data 11 is minimized. , By translating one or both of these objects. For data representing an object moved by this parallel movement, the coordinates of the surface of the measurement object 1 are changed.

  This alignment can be performed, for example, as follows. First, for each lattice cell of the shape data 11, the distance d to the closest point in the measurement data 10 acquired in step S102 is calculated. Next, a value D is obtained by adding the distances d for all lattice cells of the shape data 11. If the value D is larger than a preset threshold value, an object having a shape represented by the measurement data 10 is moved in parallel, the value of the coordinates of the measurement data 10 is changed, and the value D is determined again. The above processing is performed until the value D becomes smaller than the above threshold, and the position of the object having the shape represented by the measurement data 10 is determined. The processing unit 8 can read the threshold value of the value D.

  In step S103, the positions of one or both of the object of the shape represented by the measurement data 10 and the object of the shape represented by the shape data 11 are changed as described above, and the positions of these objects match each other. As described above, the coordinates of the surface of the measurement object 1 are changed for one or both of the measurement data 10 and the shape data 11.

  In step S104, the processing unit 8 determines, with respect to the shape data 11 aligned with the measurement data 10 in step S103, whether or not each grid cell is a grid cell to be measured. A grid cell determined to be measured is a grid cell representing a region to be measured (a region from which surface shape data can be obtained without any loss).

  FIG. 6 is an explanatory diagram of a method of determining whether each grid cell of the shape data 11 is a grid cell to be measured. FIG. 6 shows measurement data 10 and shape data 11 after alignment on the left side, and shape data 11 and an area 12 to be measured (lattice cells to be measured) on the right side. The grid cells of the shape data 11 are assigned identification numbers A1 to A12.

  For example, the number density of measurement points in the grid cell can be used to determine whether the grid cell is the grid cell to be measured. The measurement point is a point on the surface of the measurement object 1 at which the measurement data 10 is acquired, and is a point cloud of the measurement data 10. Hereinafter, a determination method using the number density of measurement points in the grid cell will be described.

  First, for each data of the measurement data 10 (point group indicating the coordinates of the surface of the measurement target 1), the nearest grid cell is obtained from the shape data 11. Next, one lattice cell is selected, and the number of pieces of measurement data 10 with the selected lattice cell closest is counted. Then, the number density of measurement points in this grid cell is calculated by dividing this number by the area of the selected grid cell. If the calculated number density of measurement points is larger than the threshold value set in advance according to the size of the grid cell, it is determined that this grid cell is the grid cell to be measured (the area 12 to be measured). The above processing is performed on all the grid cells of the shape data 11, and the area 12 to be measured of the measurement object 1 is obtained. In the example shown in FIG. 6, the grid cells of identification numbers A1, A2, A3, A6, A10, A11, and A12 are grid cells to be measured, that is, areas 12 to be measured. The processing unit 8 can read the threshold of the number density of measurement points.

  In step S105, the processing unit 8 identifies the identification number of the grid cell (the area 12 to be measured) determined to be the grid cell to be measured in step S104, together with the set of measurement conditions used for the measurement in step S102. It is stored in the storage unit 7.

  FIG. 7 is a diagram showing a set of measurement conditions C1 stored in the storage unit 7 and identification numbers of lattice cells (the area 12 to be measured) determined to be measured. The processing unit 8 measures the position coordinates (x, y, z) and rotation angle φ of the robot arm 3, the rotation angle θ of the rotation stage 4, and the movement start position, movement end position, and movement speed of the scanning unit 5. A set of conditions C1 and identification numbers A1, A2, A3, A6, A10, A11, A12 (see FIG. 6) of grid cells to be measured obtained under this set of measurement conditions C1 are stored together Save to 7.

  The process of step S101 to step S105 is repeated several times. Therefore, the inspector inputs a plurality of sets of measurement conditions Cj (j = 1, 2,..., M) to the processing unit 8 in step S101 (m is the number of the set of measurement conditions). However, one set of measurement conditions input in step S101 is a set of measurement conditions different from the set of measurement conditions already input and stored in the storage unit 7. That is, the measurement conditions are changed and steps S102 to S105 are performed. The number m of repeating step S101 to step S105 (that is, the number m of sets of measurement conditions) can be determined according to the three-dimensional shape and size of the measurement object 1.

  In step S1, in this way, a plurality of sets of measurement conditions Cj (j = 1, 2,..., M) and grid cells to be measured corresponding to the sets of measurement conditions Cj (area 12 to be measured) Is stored in the storage unit 7 (see FIG. 7).

  In addition, when the measurement object 1 is a mass-produced cast product, the unevenness of the surface of the measurement object 1 varies depending on the individual. If the incident angle of the laser beam projected is large due to the unevenness of the surface of the measurement object 1, the measuring device 2 can not detect the reflected light from the measurement object 1, and data loss may occur. As described above, in the measurement of the surface shape of the measurement target 1, data loss may occur due to the individual difference of the measurement target 1.

  Therefore, in order to reduce the influence of the individual difference of the measurement object 1 which is a mass-produced casting product, steps S102 to S105 are performed on a plurality of samples of the measurement object 1 under the same set of measurement conditions. It can also be done. In step S105, the processing unit 8 stores, in the storage unit 7, the identification number of the grid cell determined to be commonly measured among all the samples.

  Therefore, the following process can be performed on a plurality of samples of the measurement target 1. First, step S102 to step S105 are performed on a plurality of samples of the measurement object 1 under the same set of measurement conditions, and the grid cell to be measured corresponding to the set of measurement conditions (the area 12 to be measured) ) (Identification number common to all samples) is stored in the storage unit 7. Next, the measurement conditions are changed, and steps S102 to S105 are performed on a plurality of samples of the measurement object 1 with this set of measurement conditions, and the grid cell to be measured corresponding to the one set of measurement conditions. The identification number is stored in the storage unit 7. These processes are repeated by the number of sets of measurement conditions.

  Alternatively, the following process may be performed on a plurality of samples of the measurement target 1. Steps S <b> 102 to S <b> 104 are performed on one sample of the measurement object 1 by the number of measurement condition sets under each measurement condition set. Next, the sample of the measurement target 1 is changed, and for the changed sample, steps S102 to S104 are performed under the measurement conditions of each set by the number of sets of measurement conditions. These processes are repeated for the number of samples. Then, for each set of measurement conditions, the identification number of the grid cell (the area 12 to be measured) common to all the samples is stored in the storage unit 7.

  As described above, even when the measurement object 1 is a mass-produced cast product and there are individual differences in surface irregularities, the influence of the individual differences is reduced, and a plurality of sets of measurement conditions and each set of The identification number of the grid cell to be measured (the area 12 to be measured) corresponding to the measurement condition can be stored in the storage unit 7.

Next, step S2 will be described. In step S2, the processing unit 8, based on information stored in the storage unit 7, determines the measurement condition i _k at each measurement times k for the specified number of measurements n.

  FIG. 8 is a flowchart showing the procedure of step S2. Step S2 has steps S201 to S203.

  In step S201, the processing unit 8 calculates the lattice cells to be measured corresponding to the measurement conditions Cj (j = 1, 2,..., M) of all the sets and the measurement conditions Cj stored in the storage unit 7. The identification number of (the area 12 to be measured) is read from the storage unit 7. The processing unit 8 further reads the number of measurements n. The number of times of measurement n is a numerical value indicating how many times the measurement is performed, and can be set in advance according to the inspection time required for the measurement target 1. Further, the value of the parameter k (k = 1, 2,..., N) indicating the number of times of measurement (how many times of measurement) is set to 1.

In step S202, the processing unit 8 calculates the sum of the areas of the grid cells (area 12 to be measured) to be measured for each set of measurement conditions Cj, and measures the measurement conditions Cj for which the sum of the areas is maximum. It is determined as the measurement conditions i _k times k (k-th measurement). In the example shown in FIGS. 6 and 7, for the measurement condition C1, the sum of the areas of the grid cells of the identification numbers A1, A2, A3, A6, A10, A11, and A12 is calculated.

In step S203, the processing unit 8, the identification number of the measurement to be grid cell (area 12 to be measured) for all sets of measurement conditions Cj, should grid cell (measurement to be measured for the measurement condition i _k Erase the identification number of area 12). This area 12 to be measured for the measurement condition i _k which have already been determined, is to prevent selected overlap as a region 12 to be measured for the different measurement conditions i _{k '.}

If k is not equal to n after step S203, the processing unit 8 increments the value of k by one and repeats the processes of steps S202 and S203. However, in step S203, since the region 12 to be measured for the measurement condition i _k which has already been determined is erased, in step S202, to be measured other than the region 12 to be measured for the measurement condition i _k which has already been determined The sum of the areas of the region 12 is calculated, and the measurement condition Cj at which the sum of the areas becomes maximum is determined as the measurement condition ik of the measurement count _k .

If k is equal to n after step S203, the measurement condition _ik is determined for all the measurement times k (k = 1, 2,..., N), so the processing unit 8 performs the process of step S2. Finish. Processing unit 8, in this way, the measurement times k (k = 1,2, ..., n) can be obtained measurement condition _{i k} for.

  When the surface shape of the measurement object 1 is measured with the designated number of times of measurement n by the process of step S2, an area to be measured of the measurement object 1 as a condition determination index (a region where data of the surface shape can be obtained without loss) Using the area of, the measurement conditions can be selected so that the area to be measured is as large as possible. For this reason, in the surface inspection apparatus according to the present embodiment, the largest possible area of the measurement object 1 can be measured by the designated number of times of measurement n.

Next, step S3 will be described. In step S3, the monitoring instrument 2 is measured and determined in step S2 times k (k = 1,2, ..., n) in the measurement condition _{i k} for, for measuring the surface shape of the measurement object 1. This measurement (main measurement), relative to one of the measurement object 1, a plurality of times while changing the measurement condition i _k (n times) to run.

In step S3, the control unit 6, the processing unit 8 measuring times sent by k (k = 1,2, ..., n) in accordance with the measurement condition _{i k} for the position coordinates of the robot arm 3 (x, y, z) The control device 2 measures the surface shape of the measurement object 1 by controlling the rotation angle φ, the rotation angle θ of the rotation stage 4, the movement start position, movement end position, movement speed, and the like of the scanning unit 5. (Perform the main measurement). Note that the measurements do not necessarily have to be performed in the order of the measurement conditions i ₁ , i ₂ ,... I _n , and the time taken to control the robot arm 3, the rotation stage 4 and the scanning unit 5 becomes as short as possible. It may be executed in the order of conditions.

Although not shown in FIG. 1, the surface inspection apparatus may include a display unit (for example, a display) connected to the processing unit 8. The display unit displays the measurement object 1 and the measurement condition i _k. Display unit further with a color grid cells to be measured corresponding to the measurement conditions i _k (region 12 to be measured) may be displayed measurement object 1. With such a display, the inspector can confirm the area to be measured of the measurement object 1 during measurement, and can also grasp the area not measured.

  Next, step S4 will be described. In step S4, the processing unit 8 determines the presence or absence of a defect on the surface of the measurement object 1 using the measurement data acquired in the measurement of step S3.

  In step S4, the processing unit 8 calculates, for example, the distance between the object of the shape represented by the measurement data acquired in the measurement of step S3 and the object of the shape represented by the shape data 11, and this distance is set in advance. If it is larger than the threshold value, it is determined that the surface of the measurement object 1 has a defect. This distance can be obtained from the coordinates of positions corresponding to each other in the measurement data and the shape data 11. As described in step S103, the measurement data is a point group indicating the coordinates of the surface of the measurement object 1, and the shape data 11 is data including the coordinates of the surface of the measurement object 1.

  Alternatively, the processing unit 8 can calculate the curvature at each point of the measurement data, and determine that the surface of the measurement object 1 has a defect if the curvature exceeds a preset range.

  The value used to determine the presence or absence of a defect does not have to be a distance or a curvature, and may be a value obtained by extracting data indicating the shape of a curve from the acquired data and differentiating each coordinate component of these data.

  The measurement object 1 after the end of step S4 is moved by the scanning unit 5 to the unloading unit not shown in FIG. The carry-out unit carries out the measurement object 1 determined as having no defect as a passable product to the outside of the surface inspection apparatus, divides the measurement object 1 determined as having a defect as a passable product as a defective product. Take it out of the surface inspection device. At this time, the display unit connected to the processing unit 8 three-dimensionally displays the object of the shape represented by the measurement data acquired in the measurement of step S3 so that the inspector can grasp the position and the shape of the defect. Alternatively, a color may be displayed on a portion represented by data derived as a result of the determination that there is a defect, or the portion may be displayed surrounded by a frame.

  The surface inspection apparatus according to the present embodiment measures the widest possible area of the measurement object 1 such that there is no loss of data at a predetermined number of times of measurement n (that is, a predetermined inspection time). Can. Therefore, even if the measurement object 1 is a mass-produced cast product having a complicated shape, the surface shape can be measured automatically and accurately at high speed to determine the presence or absence of a defect. Moreover, since the surface inspection apparatus according to the present embodiment can specify the area to be measured, it also has the effect of being able to grasp the area not measured of the measurement object 1.

  A surface inspection apparatus according to a second embodiment of the present invention will be described.

  FIG. 9 is a view showing the configuration of a surface inspection apparatus according to a second embodiment of the present invention. The surface inspection apparatus according to the present embodiment further includes a designation unit 13 connected to the processing unit 8 in the surface inspection apparatus according to the first embodiment.

  The designation unit 13 stores the priority set for each grid cell of the shape data 11 of the measurement object 1. The priority is a numerical value indicating the height of the necessity of inspection for each part (lattice cell) of the surface of the measurement object 1. For example, the higher the necessity for inspection, the larger the value. The priority of each grid cell can be input to the designating unit 13 in advance by the inspector or during the inspection of the measurement object 1.

  FIG. 10 is a flowchart showing the procedure of step S2 performed by the surface inspection apparatus according to the present embodiment. Step S2 in this embodiment includes steps S201, S202a, and S203. Steps S201 and S203 are the same as steps S201 and S203 in the first embodiment, but step S202a is different from step S202 in the first embodiment. Further, in step S201, in addition to the number of times of measurement n, the processing unit 8 inputs the priority of the lattice cell from the specifying unit 13 as well, which is different from step S201 in the first embodiment. Hereinafter, step S202a will be described.

In step S202a, the processing unit 8 calculates the sum of the priorities of the grid cells (area 12 to be measured) to be measured for each set of measurement conditions Cj (j = 1, 2,..., M). the measurement condition Cj sum of time is maximized, the measurement times measurement condition of k (k-th _{measurement) i k (k = 1,2,} ..., n) is determined as.

In the second embodiment, when the surface shape of the measurement object 1 is measured with the designated number of times of measurement n by the process of step S2, priority (necessity of inspection for each portion of the surface of the measurement object 1) as a condition determination index sex) was used to preferentially select a measurement condition Cj for measuring the high priority portion as the measurement condition i _k of the measurement. For this reason, in the surface inspection apparatus according to the present embodiment, it is possible to preferentially measure a portion where the necessity of the inspection of the measurement object 1 is high.

  The present invention is not limited to the above embodiments, and various modifications are possible. For example, the above embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to the aspect having all the described configurations. Also, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. In addition, it is possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete part of the configuration of each embodiment or to add or replace another configuration.

  DESCRIPTION OF SYMBOLS 1 ... measurement object, 2 ... measurement machine, 3 ... robot arm, 4 ... rotation stage, 5 ... scanning part, 6 ... control part, 7 ... storage part, 8 ... processing part, 9 ... line laser, 10 ... measurement data 11: shape data 12: area to be measured 13: designation part.

Claims (8)

An optical measuring device that measures the surface shapes of a plurality of measurement objects having a three-dimensional shape;
A moving unit that moves the measurement object and the optical measurement device relative to each other;
A rotational stage which rotationally moves the measurement object;
A control unit that controls the moving unit and the rotation stage;
A processing unit that controls the control unit and the optical measuring instrument;
Equipped with
The measurement condition is a condition under which the control unit controls the moving unit and the rotation stage,
The preliminary measurement is performed by the optical measurement machine performing measurement on a part of the measurement objects among the measurement objects;
It is assumed that the main measurement is performed by the optical measurement machine on at least the remaining number of the measurement objects among the measurement objects;
The condition determination index is an index for determining the measurement condition used for the main measurement,
The processing unit is
Enter multiple sets of the measurement conditions,
Using the results of the preliminary measurement performed by the optical measuring device under each measurement condition of each set, the area to be measured of the object to be measured is determined for the measurement condition of each set;
The measurement condition for each measurement cycle is determined from among the plurality of sets of measurement conditions using the condition determination index and the area to be measured for the measurement conditions of each set.
Configured as
The optical measuring machine is configured to perform the main measurement when the control unit controls the moving unit and the rotation stage according to the measurement condition for each measurement cycle.
Surface inspection device characterized by. Assuming that the measurement point is a point on the surface of the measurement object from which data of the preliminary measurement has been acquired,
The processing unit is
Inputting shape data that is a set of grid cells representing the surface of the measurement object;
A grid cell whose number density of the measurement points is larger than a preset threshold value is set as the area to be measured for the measurement condition of each set.
Is configured as
The surface inspection apparatus according to claim 1. The condition determination index is an area of the area to be measured of the measurement object,
The processing unit is configured to determine, for each of the measurement times, the measurement condition with the largest area, from among a plurality of sets of the measurement conditions.
The surface inspection apparatus according to claim 1. The condition determination index is a priority that is a numerical value indicating the necessity of inspection for each part of the surface of the measurement object,
The processing unit is configured to determine, for each of the measurement times, the measurement condition that maximizes the priority, from among a plurality of sets of the measurement conditions.
The surface inspection apparatus according to claim 1. An optical measuring device that measures the surface shapes of a plurality of measurement objects having a three-dimensional shape;
A moving unit that moves the measurement object and the optical measurement device relative to each other;
A rotational stage which rotationally moves the measurement object;
A control unit that controls the moving unit and the rotation stage;
A processing unit that controls the control unit and the optical measuring instrument;
Is used,
The measurement condition is a condition under which the control unit controls the moving unit and the rotation stage,
The preliminary measurement is performed by the optical measurement machine performing measurement on a part of the measurement objects among the measurement objects;
It is assumed that the main measurement is performed by the optical measurement machine on at least the remaining number of the measurement objects among the measurement objects;
The condition determination index is an index for determining the measurement condition used for the main measurement,
Inputting a plurality of sets of the measurement conditions into the processing unit;
The area where the processing object should measure the measurement object with respect to the measurement condition of each set, using the result of the optical measurement machine performing the preliminary measurement under the measurement condition of each set. Step of obtaining
Determining the measurement condition for each measurement cycle from among the plurality of sets of measurement conditions using the condition determination index and the area to be measured for the measurement condition of each set; ,
A step of performing the main measurement when the optical measurement machine controls the moving unit and the rotation stage according to the measurement condition of each measurement cycle by the control unit;
The surface inspection method characterized by having. Assuming that the measurement point is a point on the surface of the measurement object from which data of the preliminary measurement has been acquired,
In the process in which the processing unit determines an area to be measured of the measurement target for each set of the measurement conditions, the processing unit includes:
Inputting shape data that is a set of grid cells representing the surface of the measurement object;
A grid cell whose number density of the measurement points is larger than a preset threshold value is set as the area to be measured for the measurement condition of each set.
The surface inspection method according to claim 5. The condition determination index is an area of the area to be measured of the measurement object,
In the process in which the processing unit determines the measurement condition for each of the measurement times among the plurality of sets of measurement conditions, the processing unit determines the plurality of sets of measurement conditions in which the area is maximized. Determined from the measurement conditions for each of the measurement times,
A surface inspection method according to claim 5 or 6. The condition determination index is a priority that is a numerical value indicating the necessity of inspection for each part of the surface of the measurement object,
In the process in which the processing unit determines the measurement condition for each of the measurement times among the plurality of sets of measurement conditions, the processing unit determines the measurement condition with the highest priority to be a plurality of sets of measurement conditions. It is determined for each of the measurement times among the measurement conditions,
A surface inspection method according to claim 5 or 6.

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