JP4876388B2 - Surface shape measuring method and measuring system - Google Patents

Description

The present invention relates to a surface shape measuring method and a measuring system for quantitatively measuring the shape of the irregularities that occurred on the surface having a complex curved shape in the wetted portion of the fluid machine as the measured object.

  In machinery and the like, there are various technical fields in which a change in the surface shape of a solid is a problem. For example, wear of sliding parts and corrosion or erosion of metals are important problems that may determine the life of machinery. Among them, in a fluid machine, a change in the surface shape inside the machine due to cavitation erosion described below often becomes a problem, and accurate measurement of the amount of cavitation erosion is a big problem.

  With the recent reduction in size and weight of fluid machines, the operating conditions of liquid turbo pumps (hereinafter referred to as pumps) have become increasingly severe. This is because a large flow rate can be generated with a small pump by operating the pump at a higher speed.

  However, when the pump is operated at a high speed, a phenomenon called cavitation occurs inside the pump, and the inside of the pump may be damaged by cavitation erosion that occurs accordingly. Cavitation is a phenomenon in which, when a portion having a pressure lower than the vapor pressure of the liquid is generated in the liquid, vapor bubbles are generated in the portion. When bubbles due to cavitation suddenly return to liquid at the high pressure part, shock pressure is locally generated at the part, and the pressure may act on the inner wall or blade surface of the pump and erode the surface of the part. . This is cavitation erosion.

  It is said that the strength of cavitation generated in the pump is proportional to the cube of the peripheral speed of the pump blades. Therefore, cavitation erosion when operating the pump at high speed is very important from the standpoint of maintaining pump performance and managing the life. It becomes an important issue. The inside of the pump in which cavitation erosion has occurred is sometimes partially eroded in a spongy manner, leading to generation of a through hole. In such a case, the performance of the pump is remarkably lowered, and in some cases, it does not function as a pump. Therefore, measurement of the amount of erosion is very important as well as suppression of erosion.

  As a method for measuring the amount of erosion, generally, as described in Non-Patent Document 1, a method for precisely measuring the surface shape of the eroded surface, or as described in Patent Document 1, Methods are used to measure the mass loss of a material that has undergone pitting. As a method for measuring the surface roughness shape of a workpiece, an inclination correction method for removing a contour shape portion of the workpiece from measurement data as described in Patent Document 2 has been proposed.

More specifically, as in Non-Patent Document 1, in order to precisely measure the shape of the eroded surface, a surface shape replica is collected from the eroded surface, and the contact type surface shape is obtained. A method of measuring surface irregularities with a measuring device or measuring a surface shape from a cross section of a replica cut by a plane perpendicular to the surface has been common. Further, as shown in Patent Document 1, in order to measure the mass loss of a material subjected to erosion, a method of subtracting the mass after the occurrence of erosion from the initial mass of the object to be measured, A method inferred from the cross-sectional shape of the replica has been common. Further, as shown in Patent Document 2, when measuring the surface roughness shape of a workpiece, the measurement data includes a roughness component, a swell component, and a contour shape component. It is necessary to extract the roughness curve by removing the components and calculate the surface roughness from this roughness curve, but the idea of removing the interpolation curve set at the time of measurement from the measurement data is disclosed Yes.
Edited by Yoji Kato: New edition of Cavitation, Tsuji Shoten (1999), page 242 JP 2002-267484 A JP-A-8-75448

  The above prior art is effective for measuring a representative value of erosion amount. That is, since the measurement value in the method of Non-Patent Document 1 is a two-dimensional or three-dimensional pit shape curve, it is possible to obtain a representative value of the erosion amount by analyzing this curve in detail. However, since the measurement values obtained by the technique of Non-Patent Document 1 are measurement values of individual pit shapes on the eroded surface, the amount of information is small, which is the most problematic in cavitation erosion. There existed a subject that there exists a possibility that the site | part where the amount of foods becomes the maximum may not be measured correctly.

  In order to solve the above-described problem, for example, a method of obtaining information on a three-dimensional shape of the entire eroded surface by repeatedly performing a plurality of measurements using a contact-type surface shape measuring device is conceivable. By adopting this method, the amount of information that can be acquired is greatly increased, and the possibility that a site where the amount of erosion is maximized can be measured is increased. For example, the measurement surface is flat, a known two-dimensional curved surface, or a known There was a certain effect when it was a three-dimensional curved surface. However, since the pump blade surface and the inner surface of the casing surrounding the pump are generally complicated three-dimensional curved surfaces, it is very difficult to distinguish the unevenness due to erosion from the unevenness existing from the beginning even if the amount of erosion is measured. It was an obstacle to quantify the amount of erosion.

  On the other hand, the measured value in the method of Patent Document 1 can determine the representative value of the erosion amount by measuring the mass loss in the entire object to be measured that has undergone erosion. However, the method of Patent Document 1 is effective only when the amount of mass loss, that is, the amount of erosion is considered to be sufficiently large and significant compared to the measurement error range of the mass of the object to be measured. Therefore, for example, it has been very difficult to determine a mass loss of several milligrams generated on the surface of a pump blade having a mass of 100 kilograms or more. Patent Document 2 merely shows the idea of removing an interpolation curve from measurement data in order to remove unnecessary components such as contour shape components from the measurement data in two-dimensional surface roughness measurement. .

An object of the present invention is to provide a method and system for accurately and quantitatively measuring the shape of irregularities generated on a surface having a curved surface shape in a wetted part of a fluid machine as an object to be measured .

In order to solve the above-mentioned problem, the first means of the present invention is the shape of the unevenness due to the damage accompanied by the thinning generated on the curved surface of the wetted part in the fluid machine having the wetted part as the object to be measured. In a surface shape measuring system using a three-dimensional shape measuring device for measuring the surface, the three-dimensional shape measuring device measures the surface shape before and after the occurrence of unevenness at each coordinate, and then the surface before the occurrence of the unevenness. As a reference position obtained as a plurality of intersections of straight lines drawn on the initial surface when transforming coordinates so that one of the coordinates in the shape and the subsequent surface shape matches the other coordinates As a result of coordinate conversion based on the reference point, the surface shape before the occurrence of the unevenness is compared with the subsequent surface shape, and the initial surface shape data is subtracted from the surface shape data after the occurrence of the unevenness. It is characterized by extracting the shape of the unevenness due to the damage accompanied by the thinning generated based on the fruit.

Further, in order to solve the above-mentioned problem, the second means of the present invention is to provide unevenness due to damage accompanied by thinning generated on the curved surface of the wetted part in the fluid machine having the wetted part as the object to be measured. in the surface shape measuring method for measuring the shape by a three-dimensional shape measuring apparatus, as steps to be executed by the three-dimensional shape measurement device, the steps of preliminarily measuring the previous surface shape generated by the unevenness occurred subsequent uneven surface It was drawn on the initial surface when transforming the coordinates so that one of the coordinates measured before and after the step of measuring the shape again and the coordinates of one of the surfaces measured before and after the unevenness coincided with the other coordinates . A step of performing coordinate transformation based on a reference point as a reference position obtained as a plurality of intersections of straight lines, and a surface shape after the occurrence of unevenness by comparing the surface shape before the unevenness with the subsequent surface shape A step of subtracting the initial surface shape data from the shape data, and a step of extracting the shape of the unevenness due to the damage accompanied by the thinning generated based on the result of the subtraction .

According to the present invention, the shape change due to the generation of unevenness due to damage accompanied by thinning the initial shape of the surface of the liquid contact portion of the fluid machine is a measuring object, it can be easily and accurately measured.

The surface shape Johaka constant system according to an embodiment of the present invention will be described below with reference to FIGS. Figure 1 is a diagram for explaining the basic concept of measurement of surface (3D) shape of the object to be measured at the surface type Johaka constant system according to an embodiment of the present invention. FIG. 2 is a configuration diagram showing a three-dimensional shape measuring apparatus that measures a three- dimensional surface shape, which is a surface shape measuring system according to the present embodiment. FIG. 3 is a diagram illustrating a method of coordinate conversion before and after occurrence of unevenness in surface shape measurement according to the present embodiment.

 In FIG. 1, reference numeral 1 denotes an initial surface shape of a measurement object in the present embodiment (which will be described later, for example, a rotor blade of a pump), and is typically a three-dimensional curved surface (stepped surface shape). 2) is a surface shape after the unevenness 11 is generated on the surface of the measurement object. Here, since the surface shape 2 after the occurrence of unevenness includes the unevenness to be measured in the present embodiment, the unevenness in the surface shape 2 is originally intended to be directly quantified, but the surface of the object is also in the initial shape. Since it is a complicated three-dimensional curved surface (surface shape similar to the uneven shape generated after using the impeller blades), it is very difficult to quantitatively measure only the generated unevenness.

  Therefore, in the embodiment of the present invention, by comparing the initial surface shape 1 in FIG. 1 and the surface shape 2 after the occurrence of unevenness, the unevenness generated on the surface of the measurement object is similar to the unevenness of the background that existed from the beginning. It can be separated from the object (three-dimensional curved surface), and the shape of the irregularities 11 on the plane from which the initial irregularities similar to the irregularities (three-dimensional curved surface) as indicated by reference numeral 3 are eliminated can be accurately captured.

  The surface shape shown in FIG. 1 in this embodiment is measured by, for example, a three-dimensional shape measuring apparatus shown in FIG. The types of three-dimensional shape measuring apparatuses are roughly classified into contact type and non-contact type, and the surface shape of an object is measured using a stylus and a light beam, respectively. This embodiment can be implemented using any of these types of surface shape measuring devices. The contact-type surface shape measuring apparatus has an advantage that the measurement result is not affected by the optical surface state of the object to be measured, such as reflectance and transmittance, but the operation of the stylus cannot follow a sharp shape change. In addition, there are drawbacks such as low spatial resolution in general. On the other hand, the non-contact type surface shape measuring apparatus has advantages and disadvantages opposite to the advantages and disadvantages of the contact type shape measuring apparatus described above.

  In the present embodiment, the surface shape of the object to be measured 22 was measured using a three-dimensional shape measuring apparatus having a laser displacement meter 21 as shown in FIG. In this measuring apparatus, the laser displacement meter 21 can be moved to an arbitrary position in the space above the object to be measured 22 using the X stage 23, the Y stage 24, and the Z stage 25. The shape can be measured. The measurement result data is sent from the control system 26 to the data processing system 27 and the image display system 28, where data processing and image display of the measurement results are performed, respectively.

  In the present embodiment, the data on which the three-dimensional surface shape is based is a set of coordinate data in the space, and the origin and coordinate axes of the surface shape data at the initial stage and after the occurrence of the unevenness are the three-dimensional shape measurement shown in FIG. These are the origin and coordinate axes of the XYZ stages 23, 24, 25 in the apparatus. When the measurement apparatus as shown in FIG. 2 is employed, the coordinates of the initial surface and the surface after the occurrence of the unevenness are obtained unless the measurement object 22 at the initial stage and after the occurrence of the unevenness is placed at the same position on the XYZ stages 23, 24, 25 The coordinates of cannot be compared directly. However, it is difficult to place the measurement object at the initial stage and after the occurrence of unevenness at the same position on the XYZ stages 23, 24, 25 in the same direction.

  Therefore, in this embodiment, in order to compare measurement data so that the measurement results of the initial surface shape 1 in FIG. 3 and the surface shape 2 after the unevenness generation are not measured at different coordinates, before and after the unevenness generation, Coordinate conversion processing is performed on the surface shape data. That is, it is difficult to position and measure each measurement object 22 having the initial and uneven surface shapes with respect to the X, Y, and Z stages without any error. Then, coordinate conversion processing is performed on each piece of data obtained from the measurement object 22 that is appropriately installed, and measurement is performed with the same coordinates.

  In the coordinate conversion, reference points (or reference positions) provided in advance on the surface whose shape is to be measured, that is, the reference points 31 to 34 in the initial shape in FIG. 'Perform based on'. In FIG. 3, all of the initial surface shape data is converted by a method in which the coordinates of the reference points measured on the initial surface and the surface after the occurrence of the unevenness match. At this time, there is no major problem even if the surface shape data after the occurrence of unevenness is converted, but the data after the occurrence of unevenness contains information on minute unevenness, and coordinate conversion may affect the shape of the unevenness. Therefore, the initial surface shape data is converted.

Next, details of the coordinate conversion method will be described. In the present embodiment, a known point on the initial surface, for example, the coordinate of the reference point 31 in FIG. 3 is A ₁ , the coordinate of the known reference point 31 ′ after occurrence of the irregularities corresponding to the reference point 31 is A _2, and A Let the components of ₁ and A ₂ be (x ₁ , y ₁ , z ₁ ) and (x ₂ , y ₂ , z ₂ ), respectively. Assuming that a general coordinate transformation matrix in space is R, an equation for converting the point 31 to the point 31 ′ can be expressed by the following equation.

A ₂ = RA ₁ (1)
Where R is

Then, from Equation (1) and Equation (2),

Thus, it can be seen that at least four coordinates (reference points 31, 32, 33, 34 in the example of FIG. 3) are necessary to specify the matrix R. However, when some of the components of the matrix R, for example, q _x , q _y , and q _z are known prior to the coordinate transformation, the matrix R can be obtained even with three reference points. .

  As a result of the above coordinate conversion, the initial surface shape data and the background of the surface shape data after the occurrence of unevenness match, so by subtracting the initial surface shape data from the surface shape data after the occurrence of unevenness, It is possible to extract only the data.

  In addition, although the initial shape in this embodiment was measured with the three-dimensional shape measuring apparatus, it is also possible to use the initial shape data as design data used for manufacturing the object to be measured. For example, if the object to be measured is manufactured by NC (numerical control) machining, it is possible to omit the measurement of the initial shape by using the NC data as the machining reference as the initial shape data.

Next, another way of drawing the reference point in the initial shape of the object to be measured and the surface shape after the occurrence of unevenness will be described with reference to FIG. The above-described drawing method of the reference point in FIG. 3 is a point set on the initial surface, whereas the reference point in another drawing method as shown in FIG. 4 is drawn on the initial surface. Intersection points 41 to 44 at which a plurality of lines 40 intersect .

When drawing the reference point as a point as shown in FIG. 3, there is a possibility that the reference point cannot be recognized due to the change in the surface shape after the unevenness occurs. On the other hand, the method of drawing the reference point shown in FIG. 4 is that the reference point is represented by each line (each line has an arbitrary shape including a curved line on an uneven surface and a straight line on a plane. since when viewed from is the intersection of can be regarded as a straight line drawn on the surface of the surface shape including irregularities) even no longer recognize the intersection if after irregularities occur, some of the lines If it can be recognized, the position of the intersection can be accurately estimated, and the possibility that the reference point cannot be recognized is reduced.

In this embodiment uses the front end of the knife as a means to draw each line 40 on the initial surface, for example, be drawn with a needle tip, such as scoring the needle, also it had been shaped in advance grid pattern The same effect can be obtained by pressing the mold. Each line 40 described above is shown as a solid line, the same effect can be obtained in such a broken line or dotted line.

  Further, the reference point does not have to be installed, and may be, for example, a characteristic point on the initial surface or a characteristic shape on the initial surface. In this case, for example, coordinate transformation may be performed so as to minimize the sum of squares of the distance between any two points on the initial surface and the surface after the deformation has occurred.

  In addition, although the measurement object by the above-described three-dimensional shape measurement apparatus is the surface of the object to be measured before and after the occurrence of unevenness, it may be difficult to directly measure the actual object of the object to be measured on the stage. In such a case, it is possible to indirectly measure the surface shape of the object to be measured by collecting a replica from the surface of the object to be measured and measuring the surface shape.

  Next, the occurrence of irregularities in the rotor blades of the pump, which is an application example of the surface shape measuring method or system according to the present embodiment, will be described with reference to FIG. When this embodiment is applied to an internal structure of a pump that is one of fluid machines, a flow velocity is given to the fluid by rotation of a rotor blade called an impeller as shown in FIG. The cavitation described in the background art section of the present specification described above occurs on the side where the negative pressure of the impeller is generated. Therefore, cavitation erosion often occurs on the side where the negative pressure of the impeller 5 is generated, but may also occur on the inner side of the casing surrounding the impeller 5 or on the positive pressure surface of the impeller 5.

  As shown in FIG. 5, the surface shape of the impeller 5 has a complicated three-dimensional curved surface (a surface similar to the uneven shape). In the present embodiment, first, a lattice is drawn with the cutting edge of a cutter knife as shown in FIG. 6 in a portion where cavitation erosion is expected to occur on the impeller surface. The interval between the lattices is set to about 2 to 3 mm, but it is desirable to adjust according to the size of the unevenness that appears to occur on the surface. By drawing a large number of grids with a large number of lines, it is possible to finely detect the distribution of irregularities caused by cavitation erosion. Next, a replica of the surface shape was collected. An acrylic resin was used as a replica material. It was confirmed that the replica previously transferred was transferred to the replica as well as the initial surface shape. When cavitation erosion occurs in the impeller, a concave portion is generated in the impeller. However, if a replica of the impeller is taken, the concave portion of the impeller corresponds to the convex portion of the replica. Whether it is a concave portion or a convex portion, the shape change can be measured by the surface shape measuring apparatus of the present embodiment.

  Next, the pump was operated for a predetermined time under predetermined operating conditions using the impeller of FIG. After the operation, the surface of the impeller was observed, and the occurrence of cavitation erosion was confirmed at the position where the replica was collected in advance, so the replica was collected again from that position. It was confirmed that the uneven shape reflecting the cavitation erosion and the previously drawn lattice were transferred well to the replica.

  Next, the surface shape of the replica collected from the impeller blade surface (for example, the surface) before and after the pump operation was measured using a laser three-dimensional shape measuring apparatus. Schematic diagrams of the measurement results are shown in FIGS. 7 and 8 before and after operation, respectively. 7 and 8, it is shown that the height increases in the paper direction from black to white (the black portion is concave and the white portion is convex). The black and white patterns are almost the same measurement results, but cannot be exactly matched (because the positions of the replicas before and after pumping are not perfectly matched). Therefore, coordinate conversion is performed to accurately match the coordinates. As a reference for this coordinate transformation, an intersection of previously drawn grids is used.

Specifically, an equation for obtaining a matrix R for converting one reference point 71 (coordinate A ₁₁ ) shown in FIG. 7 into coordinates corresponding to the reference point 81 (coordinate A ₂₁ ) in FIG. Using equation (1) above,
A ₂₁ = RA ₁₁ (4)
The coordinate transformation matrix R in the equation (4) can be specified using the coordinates of the four reference points in FIGS. 7 and 8 respectively.

  Next, the coordinates of all the points in FIG. 7 are converted into the coordinates of FIG. 8 using the specified coordinate transformation matrix R. FIG. 9 shows an initial shape after coordinate transformation, which is an aggregate of points thus obtained.

  In the coordinates of the points constituting the initial shape after the coordinate conversion and the coordinates of the points constituting the shape after the occurrence of the unevenness, the difference between the z coordinates of the points where the x coordinate and the y coordinate are respectively matched is calculated. When the z-coordinate thus calculated and the points having the corresponding x-coordinate and y-coordinate are displayed in the coordinate space, the result is as shown in FIG. Since FIG. 10 is a set of points having coordinates obtained by subtracting the z coordinate of the initial shape before the occurrence of unevenness from the z coordinate after the occurrence of unevenness, only the shape of the unevenness generated purely by cavitation erosion is shown.

  Comparing FIG. 8 showing the surface shape measurement result of the impeller after operation and FIG. 10 showing the result of coordinate conversion of the measurement result before and after operation and subtracting the z coordinate before and after operation, it was difficult to recognize in FIG. It can be seen that the uneven shape can be clearly recognized in FIG. That is, in FIG. 8, since the uneven shape generated by cavitation erosion is superimposed on the initial similar uneven shape (curved surface), the change in surface shape due to cavitation erosion is unclear, and cavitation erosion While it is difficult to clarify the effect of the surface roughness on the surface roughness, in FIG. 10, the initial unevenness-like shape is effectively removed, and the change in the surface roughness due to cavitation erosion can be easily performed. This is because it can be captured accurately.

  As described above, when the method or system according to the embodiment of the present invention is used, the quantitative evaluation of the amount of cavitation erosion generated on the impeller surface of the pump can be easily and accurately performed. In addition to the pump impeller, it is effective when quantitatively measuring changes in the surface shape having irregularities from the initial stage (before operation). The application range can be used for measuring, for example, the amount of wear on the sliding surface, the pits on the corroded surface, and the thickness reduction.

  As described above, the surface shape measurement system according to the embodiment of the present invention includes the following configuration. That is, in this embodiment, the initial surface shape before unevenness is measured in advance, then the surface shape after unevenness is measured again, and the initial surface shape and the surface shape after unevenness generation are determined. By comparing, the shape of the generated unevenness is extracted. Comparison of these surface shapes can be facilitated by converting the coordinates of any one of the surface shapes before and after the occurrence of the irregularities so as to substantially coincide with the other coordinates.

  Here, the above-described coordinate conversion can be easily performed by providing a reference point that makes the measurement position clear on the surface before the unevenness occurs. When the number of reference points is four or more, the accuracy of coordinate conversion is further increased. The reference point may be a literal point, but if it is an intersection of a plurality of lines, it is possible to infer the position of the reference point from the extension of the line even if the intersection that is the reference point is not clear . Further, the reference for coordinate conversion may be a feature of the surface shape instead of a point.

  The surface shape measurement method can be easily and highly accurately measured by using a contact-type or non-contact-type three-dimensional measurement apparatus, and data processing is facilitated. In the case of using a non-contact three-dimensional measuring device, more accurate measurement can be performed by using a measuring device having a laser displacement meter. On the other hand, the surface shape before unevenness generation may be production data of the object to be measured. In addition to the surface of the object to be measured, the direct measurement object may be a replica collected from the surface.

  By applying this embodiment, it becomes easy to measure the surface shape change of the internal structure of the pump. In particular, it is preferable to apply to measuring the amount of cavitation erosion inside the pump.

It is a diagram for explaining a basic concept of measurement of surface (3D) shape of the object to be measured at the surface type Johaka constant system according to an embodiment of the present invention. It is a block diagram which shows the three-dimensional shape measuring apparatus which measures the three- dimensional surface shape used as the surface shape measuring system which concerns on this embodiment. It is a figure showing one method of the coordinate transformation before and after the unevenness | corrugation generation | occurrence | production in the surface shape measurement regarding this embodiment. It is a figure explaining the other way of drawing the reference point of coordinate transformation in this embodiment. It is a figure which shows the surface shape in the rotary blade of the pump which is an example of application of the surface shape measuring method or system which concerns on this embodiment. It is a figure which shows how to draw the reference point in the impeller blade of the pump which is an application example of this embodiment. It is a figure which shows the example of a measurement result of the surface shape in the impeller blade | wing before the driving | operation in this embodiment. It is a figure which shows the example of a measurement result of the surface shape in the impeller blade | wing after the operation | movement in this embodiment. It is the figure which coordinate-transformed the measurement result of the surface shape in the impeller blade | wing before the driving | operation in this embodiment. It is a figure which shows the result of having coordinate-transformed the measurement result of the surface shape in the impeller blade | wing before an operation | movement in this embodiment, and comparing with the measurement result of the surface shape in the impeller blade | wing after an operation | movement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Initial surface shape of measurement object 2 Surface shape after unevenness generation of measurement object 3 Surface shape after generation of unevenness by removing initial unevenness analog (curved surface) 11 Generated unevenness 21 Laser displacement meter 22 Measured object 23 X stage 24 Y stage 25 Z stage 26 Control system 27 Data processing system 28 Image display system 31-34 Reference point 31'-34 'Reference point 40 Lines 41-44 drawn on the initial surface On the initial surface intersection 71 reference point 81 reference point drawn each line

Claims (6)

In a surface shape measuring system using a three-dimensional shape measuring device for measuring the shape of irregularities due to damage caused by thinning on the curved surface of the wetted part in a fluid machine having a wetted part as a measurement object,
The three-dimensional shape measuring apparatus measures the surface shape before and after the occurrence of the unevenness at each coordinate, and then determines whether the surface shape before and after the occurrence of the unevenness is in the surface shape. When converting coordinates so that one coordinate matches the other, the coordinate conversion is performed based on a reference point as a reference position obtained as a plurality of intersections of straight lines drawn on the initial surface, and The surface roughness before and after the occurrence of unevenness is compared with the subsequent surface shape, and the initial surface shape data is subtracted from the surface shape data after the occurrence of unevenness. A surface shape measuring system characterized by extracting the shape of the surface. The surface shape measurement system according to claim 1, wherein the three-dimensional shape measurement apparatus includes a display device that displays an extraction result of the concavo-convex shape due to the damage caused by the generated thinning. system. According to claim 1 or 2, wherein the surface profile measuring system, the three-dimensional shape measuring apparatus, the surface shape measuring system comprising a TURMERIC line by a contact or non-contact measurement of the surface shape. The surface shape measurement system according to any one of claims 1 to 3, wherein the measurement of the surface shape on the curved surface of the wetted part in the fluid machine by the three-dimensional shape measurement device is performed with a replica. Surface shape measurement system characterized by   5. The surface shape measurement system according to claim 1, wherein the liquid contact portion in the fluid machine is caused by damage accompanied by the thinning due to at least one of corrosion, cavitation erosion, and wear. 5. A surface shape measuring system characterized by being an internal structure of a machine in which irregularities are generated. In a surface shape measuring method for measuring the shape of irregularities due to damage accompanied by thinning generated on the curved surface of the wetted part in a fluid machine having a wetted part as an object to be measured,
As the steps executed by the three-dimensional shape measuring apparatus, a step of measuring in advance the surface shape before the occurrence of the unevenness, a step of measuring the surface shape after the occurrence of the unevenness, and before the occurrence of the unevenness When converting the coordinates so that either one of the measured surface shapes matches the other, the reference as a reference position obtained as a plurality of intersections of straight lines drawn on the initial surface A step of performing coordinate conversion based on the point, a step of subtracting initial surface shape data from surface shape data after occurrence of unevenness by comparing the surface shape before and after the occurrence of unevenness, and the surface shape data after the occurrence of unevenness ; Extracting the shape of the unevenness due to the damage accompanied by the thinning generated based on the subtracted result, and a method for measuring the surface shape.

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