JP2020027090A - Comparison measuring machine calibration gauge and comparison measuring machine calibration method - Google Patents

Abstract

To provide a comparison measuring machine calibration gauge capable of confirming that a measurement error because of positional misalignment of an object to be measured is within a precision assurance range of a comparison measuring machine.SOLUTION: A comparison machine calibration gauge 2 mounted to a holding part 34 of a table 30 having a table body 32, and the holding part 34 movably provided in the table body 32 includes a gauge body 20, plural measurement marks (H1 to H7) provided in the gauge body 20, and at least one calibration value from among sizes of the plural measurement marks (H1 to H7) and distance among the measurement marks.SELECTED DRAWING: Figure 14

Description

  The present invention relates to a calibration gauge for a comparative measuring instrument and a method for calibrating the comparative measuring instrument.

  2. Description of the Related Art Conventionally, as a method for measuring a dimension of an object to be measured, there is a means called comparative measurement. The comparative measurement is a method of using a master (measurement standard) such as a gauge block or a ring gauge to determine the dimension of the measured object from a difference from the measured object with a measuring instrument such as a dial gauge. In the comparative measurement, a master arranged at a reference position of a stage of a comparative measuring machine is measured, and then, the object to be measured is arranged on the stage, and the object to be measured is measured.

JP 2014-052273 A

  When the DUT is placed on the stage, if the DUT is displaced from the reference position of the stage, a measurement error occurs.Therefore, the measurement error due to the displacement of the DUT is determined by the comparative measuring device. It is necessary to confirm that the accuracy is within the guaranteed range. However, a method for confirming that the measurement error due to the displacement of the object to be measured is within the accuracy guarantee range of the comparative measuring instrument has not been technically established yet.

  It is an object of the present invention to provide a calibration gauge for a comparative measuring instrument and a method for calibrating the comparative measuring instrument, which can confirm that a measurement error due to a displacement of an object to be measured is within an accuracy guarantee range of the comparative measuring instrument.

  According to one aspect of the following disclosure, a calibration gage for a comparative measuring instrument attached to a holding portion of a table having a table body and a holding portion movably provided on the table body, wherein the gauge body and A plurality of measurement marks provided on the gauge body, and a calibration gauge for a comparative measurement device including a calibration value of at least one of a size of the plurality of measurement marks and a distance between the measurement marks. Provided.

  According to another aspect of the disclosure, a gage body, a plurality of measurement marks provided on the gage body, a table for giving a predetermined displacement to the gage body, and a plurality of measurement marks are provided. Using a calibration gauge having a size and at least one calibration value of the distance between the measurement marks, measuring the size of the plurality of measurement marks or the distance between the measurement marks, Applying a predetermined displacement to the gauge main body, and after applying the predetermined displacement, measuring a size of the plurality of measurement marks or a distance between the measurement marks, Comparing the size of the plurality of measurement marks or the difference between the distances between the measurement marks before and after giving a predetermined displacement, and the calibration value. There is provided.

  According to the following disclosure, the calibration gauge for a comparative measuring instrument is a gauge body, a plurality of measurement marks provided on the gauge body, the size of the plurality of measurement marks and the distance between the measurement marks. And at least one calibration value. Further, the calibration gauge for the comparative measuring instrument is attached to a holding part of the table having a table body and a holding part movably provided on the table body.

  In the calibration method using the calibration gauge for a comparative measuring instrument, first, the size of a plurality of measurement marks or the distance between the measurement marks is measured. Next, a predetermined displacement is applied to the gauge body, and the size of the plurality of measurement marks or the distance between the measurement marks after the predetermined displacement is applied is measured. Further, the difference between the size of the plurality of measurement marks before and after the predetermined displacement is applied or the difference between the distances between the measurement marks is compared with the calibration value.

  Thereby, it can be confirmed that the measurement error due to the displacement of the object to be measured is within the accuracy assurance range of the comparative measuring instrument.

It is a perspective view showing the calibration gauge for comparative measuring machines of a 1st embodiment. It is a top view showing the calibration gauge for comparative measuring machines of a 1st embodiment. FIG. 3 is a plan view showing a state where the calibration gauge for a comparative measuring instrument of FIG. 2 is rotated by 180 °. FIG. 3 is a graph showing data obtained by measuring the calibration gauge for a comparative measuring instrument of FIG. 2 with a coordinate measuring machine. FIG. 3 is a plan view showing measurement points along a 0 ° -180 ° line of the calibration gauge for a comparative measuring instrument in FIG. 2. FIG. 6 is a plan view showing measurement points along a 0 ° -180 ° line after rotating the calibration gauge for a comparative measuring instrument of FIG. 5 by 180 °. 3 is a graph showing measurement error data of a comparative measurement obtained using the calibration gauge for a comparative measuring instrument in FIG. 2. FIG. 3 is a perspective view showing a state where the calibration gauge for a comparative measuring instrument of FIG. 2 is installed on a support table at an angle. It is a top view which shows the calibration gauge for comparative measuring instruments of the other aspect of 1st Embodiment. FIG. 10 is a plan view showing a state where the calibration gauge for a comparative measuring instrument of FIG. 9 is rotated by 180 °. It is a perspective view showing the calibration gauge for comparative measuring machines of a 2nd embodiment. It is the top view which looked at the calibration gauge for comparative measuring instruments of FIG. 11 from the upper side. FIG. 13 is a plan view showing a state where the calibration gauge for a comparative measuring instrument of FIG. 12 is rotated by 180 °. FIG. 12 is a perspective view showing a state where the calibration gauge for the comparative measuring instrument of FIG. 11 is installed on a table. FIG. 15 is a perspective view showing a state where a table on which the calibration gauge for the comparative measuring instrument of FIG. 14 is installed is installed on an inclined table. FIG. 16A is a plan view showing a state in which the calibration gauge for comparative measurement device of FIG. 14 is arranged at the 0 ° -180 ° line, and FIG. 16B is a plane showing a state in which the calibration gauge for comparative measurement device in FIG. 16A is rotated by 180 °. FIG. FIG. 17A is a plan view showing a state in which the calibration gauge for the comparative measurement device of FIG. 14 is arranged on the 45 ° -225 ° line, and FIG. 17B is a plane showing a state in which the calibration gauge for the comparative measurement device in FIG. FIG. FIG. 18A is a plan view showing a state in which the calibration gauge for comparative measurement device of FIG. 14 is arranged at a line of 90 ° to 270 °, and FIG. 18B is a plane showing a state in which the calibration gauge for comparative measurement device in FIG. FIG. FIG. 19A is a plan view showing a state in which the calibration gauge for the comparative measurement device of FIG. 14 is arranged on the 135 ° -315 ° line, and FIG. 19B is a plane view showing a state in which the calibration gauge for the comparative measurement device in FIG. 19A is rotated by 180 °. FIG. 13 is a graph showing data of a deviation amount of a comparative measurement obtained by using the calibration gauge for a comparative measuring instrument of FIG. 12 (part 1). 13 is a graph showing data on the amount of deviation in comparative measurement obtained using the calibration gauge for comparative measurement device in FIG. 12 (part 2).

Hereinafter, embodiments will be described with reference to the accompanying drawings.
1. First Embodiment (Overall Configuration)
1 to 8 are diagrams for explaining a calibration gauge for a comparative measuring instrument according to the first embodiment. As shown in the perspective view of FIG. 1, the calibration gauge for a comparative measuring instrument of the first embodiment includes a gauge main body 10. The gauge main body 10 is a flat substrate, and is preferably formed of a metal containing aluminum as a main component, ceramics, or the like. The thickness of the gauge body 10 is, for example, 10 mm to 20 mm.

  On the surface of the gauge main body 10, a plurality of spheres 5 with shafts are erected. As shown in a partially enlarged view of FIG. 1, the spherical body 5 with a shaft is formed of a spherical body 12 and a cylindrical shaft portion 14 connected to a lower end of the spherical body 12. The shaft portion 14 is formed of a small-diameter portion 14a connected to the lower end of the sphere 12 and a large-diameter portion 14b connected to the lower end of the small-diameter portion 14a.

  The large diameter portion 14b of the shaft portion 14 of the shafted sphere 5 is screwed into a screw hole provided on the surface of the gauge body 10. The diameter of the sphere 12 is set to be larger than the diameter of the large diameter portion 14 b of the shaft portion 14. In this manner, the sphere 12 is supported by the shaft portion 14 extending in the vertical direction, and is disposed at a position away from the surface of the gauge body 10 upward.

  In the first embodiment, the spheres 12 of the plurality of shafted spheres 5 are examples of the plurality of measurement marks. Thus, the plurality of measurement marks are spheres 12 radially arranged on the gauge main body 10 and provided to protrude from the surface of the gauge main body 10.

  FIG. 2 is a plan view of the calibration gauge 1 for a comparative measuring instrument of FIG. 1 as viewed from above. The gauge body 10 has an octagonal shape in plan view. The shape of the gauge body 10 in a plan view can adopt various shapes such as a round shape or a square shape in accordance with a stage (not shown) of the comparative measuring instrument. For example, the size of the gauge body 10 is set to a size that is ／ or more of the measurable range in the stage of the comparative measuring instrument. The gauge body 10 is provided with a mounting hole 10a. The mounting hole 10a is formed to penetrate from the upper surface to the lower surface of the gauge body 10.

  The spheres 12 of the spheres 5 with shafts standing from the gauge body 10 include white spheres 12a shown in white and black spheres 12b shown in black. The white sphere 12a and the black sphere 12b have different diameters. For example, the diameter of the white sphere 12a can be 6 mm, and the diameter of the black sphere 12b can be 4 mm.

  The gauge body 10 has a 0 ° -180 ° line that passes through the center position in the horizontal direction. The gauge body 10 has a 45 ° -225 ° line inclined at 45 ° from the 0 ° -180 ° line. The gauge body 10 has a 90 ° -270 ° line inclined at 90 ° from the 0 ° -180 ° line. Further, the gauge body 10 has a 135 ° -315 ° line inclined at 135 ° from the 0 ° -180 ° line.

  The white sphere P (12a) is arranged at the center position of the gauge body 10 at the intersection of the 0 ° -180 ° line and the 90 ° -270 ° line. Then, four white spheres 12a are arranged side by side at an interval from the center of the 0 ° -180 ° line to the right. Also, three black spheres 12b are arranged side by side at an interval to the left away from the center of the 0 ° -180 ° line.

  Further, four white spheres 12a are arranged side by side at an interval in a diagonally upper right direction from the center position of the 45 ° -225 ° line. Also, three black spheres 12b are arranged side by side at an interval in a diagonally lower left direction away from the center position of the 45 ° -225 ° line.

  Also, four white spheres 12a are arranged side by side with an interval upward from the center position of the 90 ° -270 ° line. In addition, three black spheres 12b are arranged side by side with an interval in a downward direction away from the center of the 90 ° -270 ° line.

  Further, four white spheres 12a are arranged side by side at an interval in a diagonally upper left direction from the center position of the 135 ° -315 ° line. Also, three black spheres 12b are arranged side by side at an interval in a diagonally lower right direction away from the center of the 135 ° -315 ° line.

  As described above, in each of the 0 ° -180 ° line, the 45 ° -225 ° line, the 90 ° -270 ° line, and the 135 ° -315 ° line defined in the gauge main body 10, white appears in one direction from the center position. The spheres 12a are arranged side by side, and the black spheres 12b are arranged side by side in the other direction away from the center position. In the following description, the 0 ° -180 ° line, the 45 ° -225 ° line, the 90 ° -270 ° line, and the 135 ° -315 ° line are also referred to as measurement lines.

  In the calibration gauge 1 for a comparative measuring instrument, the diameter of the white sphere 12a is 6 mm, the diameter of the black sphere 12b is 4 mm, and the diameter of the black sphere 12b is 2 mm smaller than that of the white sphere 12a. The black sphere 12b as the second mark and the white sphere 12a as the third mark are arranged substantially symmetrically with respect to the white sphere P (12a) as the first mark arranged at the center position of the gauge body 10. Symmetry means line symmetry, more specifically, line symmetry with respect to a straight line passing through the second mark and the third mark, with a perpendicular line passing through the center of the first mark as the axis of symmetry.

  The white sphere 12a and the black sphere 12b at the symmetric positions have the same center-to-center distance with the white sphere P (12a). The term “same” as used herein includes not only a case where they completely match, but also a case where they are slightly different. For example, focusing on the 0 ° -180 ° line, the distance DX between the center of the white sphere P (12a) arranged at the center position of the gauge body 10 and the center of the adjacent black sphere 12b is the center position of the gauge body 10. Is set to be the same as the distance DY between the center of the white sphere P (12a) arranged at the center and the center of the adjacent white sphere 12a.

  Here, as shown in FIG. 3, when the calibration gauge 1 for the comparative measuring instrument of FIG. 2 is rotated by 180 °, the left and right of the 0 ° -180 ° line are reversed. As a result, the black spheres 12b are arranged side by side on the right side of the 0 ° -180 ° line, and the white spheres 12a are arranged side by side on the left side of the 0 ° -180 ° line.

  As described above, by rotating the calibration gauge 1 for the comparative measuring instrument by 180 °, the arrangement of the white spheres 12a and the black spheres 12b having different diameters from each other is interchanged, and a state in which a pseudo displacement has occurred. That is, by rotating the calibration gauge 1 for the comparative measuring instrument by 180 °, it is possible to simulate a state where the object to be measured is displaced from the reference position of the stage of the comparative measuring instrument.

  In the present embodiment, by rotating the calibration gauge 1 for the comparative measuring instrument by 180 °, the black sphere 12b having a diameter of 4 mm is arranged at the position of the white sphere 12a having a diameter of 6 mm, and the position of the black sphere 12b having a diameter of 4 mm is arranged. A white sphere 12a having a diameter of 6 mm is arranged at the center. For this reason, it is possible to simulate a state in which the measured object is displaced by 1 mm from the reference position of the stage of the comparative measuring instrument. In the first embodiment, the step of giving a predetermined displacement to the gauge main body 10 is to rotate the gauge main body 180 ° as shown in FIGS.

  The effectiveness of the calibration gauge 1 for a comparative measuring instrument of the present embodiment was confirmed using a high-precision three-dimensional measuring instrument. Specifically, the distance between the center position (0) of the gauge main body 10 and the center of the sphere at each measurement position was measured by a three-dimensional measuring machine, and the measured values before and after 180 ° rotation were compared. FIG. 4 shows the results. The vertical axis in FIG. 4 shows the difference before and after rotation, and the horizontal axis shows the measurement position.

  The position of 0 on the horizontal axis in FIG. 4 corresponds to the white sphere P (12a) (origin) arranged at the center position of the 0 ° -180 ° line of the calibration gauge 1 for the comparative measuring instrument in FIG. The positions of 30, 85, and 140 correspond to the positions of the three white spheres 12a on the right side from the origin in FIG. 2, and the positions of -30, -85, and -140 correspond to the three black spheres on the left side from the origin in FIG. 12b.

  The difference before and after the rotation is the distance from the center position (0) in the X direction (0 ° -180 ° line) of the calibration gauge 1 for the comparative measuring instrument in FIG. 3 is a difference from the distance from the center position (0) of the 0 ° -180 ° line in FIG. 3 to each measurement position. The same measurement was performed in the Y direction (90 ° -270 ° line) of the calibration gauge 1 for the comparative measuring instrument, and the difference before and after rotation was calculated.

  As shown in FIG. 4, at each measurement position of the calibration gauge 1 for a comparative measuring instrument, the difference between the measured values of the distance before and after rotating the gauge body 10 by 180 ° is within about 0.6 μm, and the accuracy is 2 μm ±. 0.25 μm, and it was confirmed that the calibration gauge 1 for a comparative measuring instrument can be used. The accuracy is a value calculated by the calibrated three-dimensional measuring machine. Considering that the measuring accuracy of the comparative measuring machine is ± 2 μm, it is clear that the calibration gauge 1 for the comparative measuring machine is created with high accuracy. Do you get it.

(How to confirm measurement error)
Next, a method of using the calibration gauge 1 for a comparative measuring instrument of the present embodiment to confirm that a measurement error due to a positional shift of an object to be measured in a comparative measurement is within an accuracy guarantee range of the comparative measuring instrument will be described. .

  In the calibration gauge 1 for a comparative measuring instrument of the present embodiment, the measured value of the diameter of the white sphere 12a is given in advance at each position where the white sphere 12a is arranged as a calibration value. At each position where the black sphere 12b is arranged, the measured value of the diameter of the black sphere 12b is given in advance as a calibration value.

  First, the calibration gauge 1 for a comparative measuring instrument of FIG. 2 is arranged at a reference position of a stage (not shown) of the comparative measuring instrument, and the coordinates (X, Y, Z) of all the white spheres 12a and the black spheres 12b are arranged by the comparative measuring instrument. ) Is detected, and the diameters of the white spheres 12a and the black spheres 12b and the distance between the centers of the symmetric white spheres 12a and the black spheres 12b are measured from the coordinates.

  Then, the calibration gage 1 for the comparison measurement device of FIG. 2 is rotated by 180 ° on the stage of the comparison measurement device, and brought into the state of the calibration gage 1 for the comparison measurement device of FIG. The coordinates (X, Y, Z) of all the white spheres 12a and the black spheres 12b of the calibration gauge 1 for the comparative measurement machine after rotation are detected by the comparative measurement machine, and the diameters of the white spheres 12a and the black spheres 12b and the symmetric positions are detected. And the center distance between the white sphere 12a and the black sphere 12b.

  FIG. 5 shows only white spheres 12a and black spheres 12b arranged on the 0 ° -180 ° line in the calibration gauge 1 for the comparative measuring instrument of FIG. 2 for simplicity of description. As shown in FIG. 5, measurement at positions A1 and B1 of a distance DA between two points on a 0 ° -180 ° line will be described as an example. First, the coordinates of the white sphere 12a at the position A1 and the black sphere 12b at the position B1 of the distance DA between the two points of the calibration gauge 1 for the comparative measuring machine before rotation are detected. The design value of the distance DA between two points is 60 mm.

  Then, the calibration gage 1 for the comparison measurement device of FIG. 2 is rotated by 180 ° on the stage of the comparison measurement device, and brought into the state of the calibration gage 1 for the comparison measurement device of FIG. As a result, the arrangement of the white spheres 12a and the black spheres 12b having different diameters from each other is interchanged, and a state where a pseudo displacement has occurred is obtained.

  FIG. 6 shows a state where the calibration gauge 1 for the comparative measuring instrument of FIG. 5 is rotated by 180 °. Focusing on the positions A1 and B1 of the distance DA between two points in FIG. 6, the black sphere 12b is arranged at the position A1, and the white sphere 12a is arranged at the position B1. That is, the white spheres 12a and the black spheres 12b are placed in a switched state. The coordinates of the black sphere 12b at the position A1 and the white sphere 12a at the position B1 of the distance DA between the two points of the calibration gauge 1 for the comparative measuring instrument are detected.

  Next, the diameter and the center-to-center distance of the white sphere 12a and the black sphere 12b before and after rotation are measured from the obtained coordinates. By comparing the diameters of the white sphere 12a and the black sphere 12b before and after rotation with the calibration values, it can be confirmed that the measurement error due to the displacement of the measured object is within the accuracy assurance range. Further, by calculating the difference between the centers before and after rotation, it is possible to confirm that the measurement error due to the displacement at the distance DA of the 0 ° -180 ° line is within the accuracy guarantee range.

  A comparative measurement is performed in a similar measurement procedure at two positions A2 and B2 having a distance DB between two points on the 0 ° -180 ° line in FIG. 5 and at two positions A3 and B3 having a distance DC between two points. Thus, the measurement error due to the displacement of the object to be measured at each position and the displacement in the distances DB and DC can be obtained. The design value of the distance DB between two points is 170 mm. The design value of the distance DC between two points is 280 mm.

  Further, the 45 ° -225 ° line, the 90 ° -270 ° line, and the 135 ° -315 ° line of the calibration gauge 1 for the comparative measuring machine described in FIG. The difference between the comparison measurement difference value and the calibration value is calculated. This makes it possible to obtain a measurement error due to a positional shift in all directions of the measurable range of the stage of the comparative measuring instrument.

  As described above, the displacement of the X axis of the 0 ° -180 ° line and the displacement of one axis of the Y axis of the 90 ° -270 ° line, the 45 ° -225 ° line, and the 35 ° -315 ° line with respect to the stage of the comparative measuring instrument. Can be obtained when a displacement in two axes of X and Y axes is given.

  When rotating the calibration gauge 1 for comparative measurement machine by 180 °, the calibration gauge 1 for comparative measurement machine of FIG. 2 may be directly arranged on the stage of the comparison measurement machine and rotated. Alternatively, as will be described in a second embodiment described later, a table (not shown) having a table main body and a holding portion movably provided on the table main body may be arranged on a stage of a comparative measuring instrument. . The calibration gauge 1 for a comparative measuring instrument may be arranged on a holding section of a table, and the calibration gauge 1 for a comparative measuring instrument may be rotated by rotating the holding section.

  In the example of the first embodiment, the comparative measuring device guarantees the accuracy such that the measurement error becomes ± 0.002 mm (2 μm) or less when the measured object is displaced by 1 mm from the reference position of the stage. (The accuracy guarantee range in FIG. 7).

  Actually, a calibration gauge for a comparative measuring instrument shown in FIG. 1 was manufactured, and it was verified that the accuracy error of the comparative measuring instrument could be confirmed. The coordinates of the white sphere and the black sphere of the calibration gauge for the comparative measuring instrument were detected, and the center distances before and after 180 ° rotation were compared. FIG. 7 shows the result. The vertical axis in FIG. 7 indicates the difference (mm) between the centers before and after rotation, and the horizontal axis indicates the measurement location. As shown in FIG. 7, three measurement points of the 0 ° -180 ° line, 45 ° -225 ° line, and 135 ° -315 ° line of the calibration gauge 1 for the comparative measuring instrument of FIG. The difference falls within the accuracy guarantee range (± 0.002 mm) of the comparative measuring instrument, and it can be seen that the accuracy is guaranteed within these three measurement points.

  On the other hand, at the distance DC (design value: 280 mm) between the two points of the 90 ° -270 ° line of the calibration gauge 1 for the comparative measuring instrument in FIG. 2, the difference before and after rotation is about 0.0025 mm (2.5 μm). Out of the accuracy guarantee range (± 0.002 mm) of the comparative measuring instrument. Therefore, since the accuracy of this measurement point is not guaranteed, calibration of the comparison measurement device is required.

  FIG. 8 shows a state in which the calibration gauge 1 for the comparative measuring instrument of FIG. The upper surface of the support base 16 is an inclined surface, and the flat calibration gauge 1 for a comparative measuring instrument in FIG. 1 is arranged on the inclined surface. Thereby, the calibration gauge 1 for the comparative measuring instrument is arranged to be inclined at the same inclination angle as the inclined surface of the support base 16.

  By comparing and measuring the calibration gauge 1 for a comparative measuring instrument with the above-described measurement procedure of rotating the calibration gauge 1 for a comparative measuring instrument 1 by 180 ° while tilting the calibration gauge 1 for a comparative measuring instrument, the X-axis, the Y-axis, It is possible to confirm a measurement error when a displacement of three axes including the Z axis is given. The support 16 may be attached to the table (not shown) described above. That is, the calibration gauge 1 for the comparative measuring instrument is fixed to the table via the support 16. Thus, the calibration gauge 1 for the comparative measuring instrument can be rotated by rotating the holding portion of the table in a state where the calibration gauge 1 for the comparative measuring instrument is inclined.

  As described above, the calibration gage 1 for the comparative measuring instrument of the first embodiment includes the white sphere P (12a) (an example of the first mark) and the white sphere P (12a) arranged at the center position of the gauge body 10. , A black sphere 12b (an example of a second mark) and a white sphere 12a (an example of a third mark) having a size different from that of the black sphere 12b.

  By rotating the calibration gauge 1 for the comparative measuring instrument by 180 °, the arrangement of the white spheres 12a and the black spheres 12b is interchanged, and a state in which a pseudo displacement has occurred is obtained. Therefore, by comparing the distance between the centers of the white sphere 12a and the black sphere 12b before and after the rotation, it is possible to confirm a measurement error due to a positional shift between the axes connecting the white sphere 12a and the black sphere 12b. Further, since the calibration gauge 1 for the comparative measuring instrument is provided with the calibration values of the diameters of the white sphere 12a and the black sphere 12b, by comparing the measured value with the calibrated value, the measurement error due to the displacement at the measurement location is obtained. Can be confirmed.

  The gauge main body 10 used in the comparative measurement instrument calibration gauge 1 of the first embodiment is a flat substrate that extends evenly in the X and Y directions. For this reason, by setting the calibration gauge 1 for the comparative measuring instrument so as to correspond to the measurable range of the stage of the comparative measuring instrument and rotating it by 180 °, many measuring points can be measured. It can be done in a short time.

  Further, since the gauge body 10 used in the calibration gauge 1 for a comparative measuring instrument of the first embodiment can be formed from inexpensive metal mainly composed of aluminum, it can be manufactured at low cost. The gauge body 10 may be formed from ultra-low thermal expansion ceramic. Alternatively, the gauge body 10 can also be formed of a metal or resin such as iron used in a comparative measuring device. By forming the comparative measuring device and the gauge body 10 from the same material, the deformation amount when the temperature changes is the same.

  In FIGS. 2 and 3 described above, the calibration gauge 1 for the comparative measuring instrument is rotated by 180 °, and the arrangement of the white sphere 12a and the black sphere 12b having different diameters from each other is pseudo-displaced. Is occurring. In addition to this method, a table (not shown) having a holding unit movable in the X direction and the Y direction may be provided on the stage of the comparative measuring instrument.

  In this case, the first comparative measurement is performed on the calibration gage 1 for the comparative measuring instrument of FIG. 2 arranged on the table on the stage of the comparative measuring instrument. Next, without rotating the calibration gauge 1 for the comparative measuring instrument, the calibration gauge 1 for the comparative measuring instrument is moved by the movement of the holding portion of the table so as to have a predetermined positional displacement amount in the X direction and the Y direction. Is generated, a second comparative measurement is performed. The same effect as in the above embodiment can be obtained by obtaining the first measurement result and the second measurement result measured in a state where the first measurement is displaced.

(Other aspects of the first embodiment)
9 and 10 are plan views showing a calibration gauge for a comparative measuring instrument according to another aspect of the first embodiment. In FIGS. 1 to 3 described above, the white sphere 12a and the black sphere 12b of the sphere 5 with the shaft formed on the gauge body 10 are used as the measurement marks. As shown in FIG. 9, in the calibration gauge 1a for a comparative measuring instrument according to another aspect of the first embodiment, a plurality of projections 17 are provided upright from the surface of the gauge body 10 instead of a sphere. . A cylindrical body, a rectangular parallelepiped, or the like is used as the protrusion 17.

  In FIG. 9, similarly to FIG. 5 described above, only a plurality of convex portions 17 of the 0 ° -180 ° line are shown for simplification of description. As shown in FIG. 9, in the calibration gauge 1a for a comparative measuring instrument in another aspect, the diameters (sizes) of the plurality of protrusions 17 in the plan view are set to be the same. Further, the second convex portion 17b (an example of the second mark) and the third convex portion are arranged so as to be substantially symmetric with respect to the first convex portion 17a (an example of the first mark) arranged at the center position of the gauge body 10. The portion 17c (an example of a third mark) is arranged.

  The distance DE between the center of the first protrusion 17a and the center of the second protrusion 17b is different from the distance DF between the center of the first protrusion 17a and the center of the third protrusion 17c. For example, the distance DE is set to be about 1 mm longer than the distance DF. For this reason, as shown in FIG. 10, when the calibration gauge 1a for the comparative measuring instrument in FIG. 9 is rotated by 180 °, the second convex portion 17b shown in black and the third convex portion 17c shown in white are rotated. The arrangement is switched, and a pseudo displacement occurs. At each position where the first convex portion 17a and the second convex portion 17b are arranged, the distance from the center to the calibration gauge 1a for the comparative measuring instrument is previously given as a calibration value.

  In the case of using the calibration gauge 1a for a comparative measuring instrument in other aspects, the measuring procedure is as follows: first, the center of the second convex portion 17b and the third convex portion 17c of the calibration gauge 1a for the comparative measuring device before rotation in FIG. Is calculated with the first distance DG1 from the center. Further, as shown in FIG. 10, after rotating the calibration gauge 1a for the comparative measuring instrument by 180 °, the second distance DG2 between the center of the third convex portion 17c and the center of the second convex portion 17b is calculated. Further, a difference between the measurement value of the first distance DG1 and the measurement value of the second distance DG2 is calculated, and a comparison measurement difference value of the distance is obtained.

  Then, by calculating the difference between the comparison measurement difference value and the calibration value, the measurement error of the comparison measurement device can be similarly obtained. The calibration value given to the calibration gauge for the comparative measuring instrument in other aspects is the first distance DG1 before and after the rotation measured by the three-dimensional measuring machine at the above-mentioned measurement position of the 0 ° -180 ° line (FIG. 9). And the second distance DG2 (FIG. 10).

  Similarly, measurement is performed in the same measurement procedure at each position having another distance between two points (FIG. 5) on the 0 ° -180 ° line. Further, measurement is performed on other measurement lines in the same measurement procedure, and a measurement error at each position is obtained.

  As described above, the calibration method of the comparative measuring instrument in another aspect includes a step of measuring a distance between a plurality of measurement marks, a step of giving a predetermined displacement to the gauge body 10, and a plurality of measurement after giving the displacement. Measuring the distance between the measurement marks, and comparing the difference between the distance between the plurality of measurement marks before and after the displacement is applied and the calibration value.

  The calibration gauge 1 and the calibration method for a comparative measuring machine of the first embodiment can be applied to a contact or non-contact comparative measuring machine, a machine tool using comparative measurement, and the like.

2. Second embodiment (overall configuration)
FIGS. 11 to 19 are views for explaining a calibration gauge for a comparative measuring instrument according to the second embodiment. As shown in the perspective view of FIG. 11, the calibration gauge 2 for a comparative measuring instrument of the second embodiment includes a strip-shaped gauge body 20 extending in one direction. The gauge body 20 has a rectangular shape in plan view, and a cross section in a width direction orthogonal to the longitudinal direction is quadrangular.

  The gauge body 20 used in the calibration gauge 2 for a comparative measuring instrument of the second embodiment is formed from a material having a small coefficient of thermal expansion. As a preferred example, Nexera (ultra low thermal expansion ceramics) having a thermal expansion coefficient of about zero near room temperature (about 20 ° C. to 30 ° C.) is used. For this reason, even if the temperature of the measurement atmosphere changes at about 2 ° C. to 3 ° C. near room temperature, the dimensional change of the gauge body 20 is small, and the measurement error can be reduced. When the measurement error due to the temperature change of the measurement atmosphere does not matter, the gauge body 20 may be formed of a metal such as aluminum, or a general ceramic such as alumina.

  Further, seven first to seventh opening holes (H1 to H7) are arranged in the gauge body 20 at intervals. The first to seventh opening holes (H1 to H7) are formed to penetrate from the upper surface to the lower surface of the gauge body 20. In the second embodiment, the seven first to seventh opening holes (H1 to H7) provided in the gauge body 20 are examples of measurement marks. Thus, the plurality of measurement marks are holes that are arranged in a row in the gauge main body 20 and penetrate in the thickness direction of the gauge main body 20.

  A fourth opening H4 is arranged at the center of the gauge body 20, and a third opening H3, a second opening H2, and a first opening H1 are arranged on the right side of the fourth opening H4 with an interval. . Further, a fifth opening H5, a sixth opening H6, and a seventh opening H7 are arranged at an interval on the left side of the fourth opening H4 arranged at the center position of the gauge body 20.

  FIG. 12 is a plan view of the calibration gauge 2 for the comparative measuring instrument of FIG. 11 as viewed from above. As shown in FIG. 12, in the calibration gauge 2 for a comparative measuring instrument of the second embodiment, the diameters HD of the first to seventh opening holes (H1 to H7) are set to be the same. The distance D1 between the center of the fourth opening H4 and the center of the third opening H3 and the distance D2 between the center of the fourth opening H4 and the center of the fifth opening H5 are different from each other. ing.

  In the example of FIG. 12, the design value of the distance D1 between the fourth opening H4 and the third opening H3 is 35 ± 0.01 μm, and the design of the distance D2 between the fourth opening H4 and the fifth opening H5. The value is 36 ± 0.01 μm, and the distance differs by about 1 mm.

  The distance D3 between the fourth opening H4 and the second opening H2 is 70 ± 0.01 μm, and the distance D4 between the fourth opening H4 and the sixth opening H6 is 71 ± 0.01 μm. Differ by about 1 mm.

  The distance between the center of the first opening H1 and the center of the second opening H2 and the distance between the center of the sixth opening H6 and the center of the seventh opening H7 are determined by the third opening H3 and the fourth opening H3. It is set to 40 mm, which is 5 mm longer than the distance D1 (35 ± 0.01 mm) from H4. Therefore, the distance D5 between the fourth opening H4 and the first opening H1 is 110 ± 0.01 μm, and the distance D6 between the fourth opening H4 and the seventh opening H7 is 111 ± 0.01 μm. Are different by about 1 mm.

  The calibration gauge 2 for the comparative measuring instrument of the second embodiment is sequentially measured at a position rotated by 45 ° within the measurable range of the comparative measuring instrument as described later. For this reason, the length of the gauge main body 20 is adjusted according to the size of the measurable range of the stage of the comparative measuring machine. For example, the length may be set to ２ or more of the measurable range in the stage of the comparative measuring instrument, specifically, the length of the gauge body 20 may be set to about 270 mm and the width may be set to about 40 mm.

  In the first to seventh opening holes (H1 to H7), a ring-shaped inclined surface is provided on the front surface and the back surface of the gauge main body 20 so as to extend outward from the inner wall of the hole. ± 0.01 mm, and the diameter on the front and back surfaces is set to 28 ± 0.01 mm.

  As described above, the first to third opening holes (H1 to H3) on the right side of the fourth opening hole H4 and the fifth to seventh opening holes (H5 to H7) on the left side of the fourth opening hole H4 are the same. The distance from the center of the four opening holes H4 is different by about 1 mm.

  As described above, the calibration gauge 2 for a comparative measuring instrument of the second embodiment includes the gauge main body 20. The fourth opening H4 arranged at the center of the gauge body 20 is an example of the first mark.

  The third opening H3 and the fifth opening H5 arranged substantially symmetrically with respect to the fourth opening H4 are examples of the second mark and the third mark arranged substantially symmetrical with respect to the first mark. Alternatively, the second mark and the third mark arranged substantially symmetrically with respect to the first mark may be the second opening H2 and the sixth opening H6, or the first opening H1 and the second opening H6. It may be a seven-hole H7.

  Here, as shown in FIG. 13, when the calibration gauge 2 for the comparative measuring instrument of FIG. 12 is rotated by 180 °, the first to third opening holes (H1 to H3) are arranged on the left side of the fourth opening hole H4. The fifth to seventh opening holes (H5 to H7) are arranged on the right side of the fourth opening hole H4.

  As described above, by rotating the calibration gauge 2 for the comparative measuring instrument of FIG. 12 by 180 °, the first to third opening holes (H1 to H3) having different distances from the fourth opening hole H4 and the fifth to fifth opening holes H4 are different from each other. The arrangement with the seventh opening holes (H5 to H7) is interchanged, and a state in which a misalignment occurs in a pseudo manner is obtained. That is, by rotating the calibration gauge 2 for the comparative measuring instrument by 180 °, a state where the object to be measured is displaced from the reference position of the stage of the comparative measuring instrument can be reproduced in a pseudo manner.

  FIG. 14 shows a state in which the calibration gauge 2 for the comparative measuring instrument of FIG. The table 30 has a table body 32 and a holding portion 34 movably provided on the table body 32. Further, a pair of opposing holding portions 36 are connected to the holding portion 34, and the calibration gauge 2 for a comparative measuring instrument is pressed and fixed on one of the pair of holding portions 36.

  The holding section 34 is rotatable with respect to the table main body 32 around a fourth opening H4 (an example of a first mark) of the calibration gauge 2 for a comparative measuring instrument. By rotating the rotary knob 38 connected to the holding unit 34, the calibration gauge 2 for a comparative measuring instrument can be rotated by the rotation of the holding unit 34.

  FIG. 15 shows a state where the table 30 to which the calibration gauge 2 for the comparative measuring instrument of FIG. The support base 40 includes a horizontal plate 42 arranged in a horizontal direction, and an inclined plate 44 inclined at a predetermined inclination angle from the horizontal plate 42, and the inclined plate 44 is connected to the horizontal plate 42 by support columns 46. . The support table 40 supports the table 30 while being inclined in the thickness direction of the gauge body 20.

  By installing the table 30 to which the calibration gauge 2 for the comparative measuring instrument is fixed on the inclined plate 44 of the support 40, the calibration gauge 2 for the comparative measuring instrument can be inclined at the same inclination angle as the inclined plate 44 of the support 40. it can. Thereby, it is possible to confirm a measurement error when a displacement of three axes including the X axis, the Y axis, and the Z axis is given to the stage of the comparative measuring machine.

(How to confirm measurement error)
Next, a description will be given of a method of using the calibration gauge 2 for the comparative measuring instrument of the second embodiment to confirm that the measurement error due to the displacement of the object to be measured is within the accuracy guarantee range of the comparative measuring instrument in the comparative measurement. I do. The calibration gauge 2 for the comparative measuring device is a master for measuring the diameters of the first to seventh opening holes (H1 to H7), the distances (D1 to D6) from the center position, and the distance measured in advance by a high-precision three-dimensional measuring device. The difference value is provided as a calibration value.

  First, the table 30 to which the calibration gauge 2 for the comparative measuring instrument of FIG. 16A is fixed is arranged on a stage (not shown) of the comparative measuring instrument so as to face the X direction (0 ° -180 ° line). The coordinates of the first to seventh opening holes (H1 to H7) are detected, and the diameter and the six distances (D1 to D6) of the calibration gauge 2 for the comparative measuring machine before rotation of FIG.

  Further, as shown in FIG. 16B, by rotating the holding unit 34 of the table 30 on the stage of the comparative measuring instrument, the calibration gauge 2 for the comparative measuring instrument is rotated by 180 °. Also in the second embodiment, the step of giving a predetermined displacement to the gauge main body 20 is to rotate the gauge main body by 180 °. Accordingly, as described in FIGS. 12 and 13 described above, the first to third opening holes (H1 to H3) and the fifth to seventh opening holes whose center position is different from the fourth opening hole H4 are different from each other. The positions of the holes (H5 to H7) are interchanged, and a pseudo displacement occurs. The coordinates of the first to seventh opening holes (H1 to H7) after the 180 ° rotation in FIG. 16B are detected, and the diameter and the six distances (D1) of the calibration gauge 2 for the comparative measuring instrument after the rotation in FIG. To D6).

  Further, the first comparative measurement difference value at each position (−111 mm, −71 mm, −36 mm, −35 mm, 70 mm, 110 mm) of the 0 ° -180 ° line of the calibration gauge 2 for the comparative measuring instrument is acquired. That is, the difference between the distance D6 of the calibration gauge 2 for the comparative measuring instrument before rotation in FIG. 12 and the distance D5 of the calibration gauge 2 for the comparative measuring instrument after rotation in FIG. 13 is calculated. This difference value is the first comparison measurement difference value at the position of −111 mm in FIG.

  The difference between the distance D4 of the calibration gauge 2 for the comparative measuring instrument before rotation in FIG. 12 and the distance D3 of the calibration gauge 2 for the comparative measuring instrument after rotation in FIG. 13 is calculated. This difference value is the first comparison measurement difference value at the position of −71 mm in FIG.

  The difference between the distance D2 of the calibration gauge 2 for the comparative measuring instrument before rotation in FIG. 12 and the distance D1 of the calibration gauge 2 for the comparative measuring instrument after rotation in FIG. 13 is calculated. This difference value is the first comparison measurement difference value at the position of −36 mm in FIG.

  The difference between the distance D1 of the calibration gauge 2 for the comparative measuring instrument before rotation in FIG. 12 and the distance D2 of the calibration gauge 2 for the comparative measuring instrument after rotation in FIG. 13 is calculated. This difference value is the first comparison measurement difference value at the position of 35 mm in FIG.

  The difference between the distance D3 of the calibration gauge 2 for the comparative measuring instrument before rotation in FIG. 12 and the distance D4 of the calibration gauge 2 for the comparative measuring instrument after rotation in FIG. 13 is calculated. This difference value is the first comparison measurement difference value at the position of 70 mm in FIG.

  The difference between the distance D5 of the calibration gauge 2 for the comparative measuring instrument before rotation in FIG. 12 and the distance D6 of the calibration gauge 2 for the comparative measuring instrument after rotation in FIG. 13 is calculated. This difference value is the first comparison measurement difference value at the position of 110 mm in FIG.

  The difference between the calibration value (difference value) and the first comparison measurement difference value calculated by the comparison measurement device is calculated. As a result, the measurement error of the comparative measuring instrument at each position (−111 mm, −71 mm, −36 mm, 35 mm, 70 mm, 110 mm) of the 0 ° -180 ° line of the calibration gauge 2 for the comparative measuring instrument is obtained, and the X-axis The measurement error of one axis can be confirmed. Also, by comparing the measured values of the diameters of the first to seventh opening holes (H1 to H7) measured in FIGS. 16A and 16B with the calibration values, the first to the seventh lines of the 0 ° -180 ° line are compared. Measurement errors at the positions of the seven opening holes (H1 to H7) can be confirmed.

  Next, as shown in FIG. 17A, the calibration gauge 2 for the comparative measuring instrument of FIG. 16B is arranged on the 45 ° -225 ° line such that the first opening H1 is arranged on the upper right side. Next, the calibration gauge 2 for the comparative measuring instrument of FIG. 17A is used to detect the coordinates of the first to seventh opening holes (H1 to H7) by the comparative measuring instrument, and to determine the diameter and the six distances (D1) before rotation of FIG. To D6).

  Thereafter, as shown in FIG. 17B, the calibration gauge 2 for the comparative measuring instrument of FIG. 17A is rotated by 180 ° on the stage of the comparative measuring instrument, and the first to seventh opening holes (H1 to H7) after the 180 ° rotation. Are detected, and the diameter and the six distances (D1 to D6) after the rotation in FIG. 13 described above are calculated.

  The second comparative measurement difference value at each position (−111 mm, −71 mm, −36 mm, 35 mm, 70 mm, 110 mm) of the 45 ° -225 ° line is obtained by the same method as the measurement procedure in FIGS. 16A and 16B described above. Respectively. By calculating the difference between the second comparative measurement difference value and the calibration value (difference value), the 45 ° -225 ° line at each position (−111 mm, −71 mm, −36 mm, 35 mm, 70 mm, 110 mm) The measurement error of the comparative measuring machine is obtained.

  Next, as shown in FIG. 18A, the calibration gauge 2 for the comparative measuring instrument of FIG. 17B is arranged on the 90 ° -270 ° line such that the seventh opening H7 is arranged on the upper side. The diameter and the six distances (D1 to D6) before rotation in FIG. 12 are calculated by measuring the calibration gauge 2 for the comparative measuring instrument with the comparative measuring instrument in the same manner as the measuring procedure in FIG. 16A described above. .

  After that, as shown in FIG. 18B, the calibration gauge 2 for the comparative measurement device of FIG. 18A is rotated by 180 ° on the stage of the comparative measurement device, and by the comparative measurement device in the same manner as the measurement procedure in FIG. 16B described above. The diameter and the six distances (D1 to D6) after the rotation in FIG. 13 described above are calculated.

  Further, the third comparative measurement difference value at each position (−111 mm, −71 mm, −36 mm, 35 mm, 70 mm, 110 mm) of the 90 ° -270 ° line by the same method as the measurement procedure in FIGS. 16A and 16B described above. Respectively. The difference between the third comparison measurement difference value and the calibration value (difference value) is calculated. As a result, measurement errors of the comparative measuring machine at each position (-111 mm, -71 mm, -36 mm, 35 mm, 70 mm, 110 mm) of the 90-270 line are obtained.

  Next, as shown in FIG. 19A, the calibration gauge 2 for the comparative measuring instrument of FIG. 18B is arranged on the 135 ° -315 ° line. By measuring the calibration gauge 2 for the comparative measuring instrument with the comparative measuring instrument in the same manner as the measurement procedure in FIG. 16A described above, the diameter and the six distances of the calibration gauge 4 for the comparative measuring instrument before rotation in FIG. (D1 to D6) are calculated. After that, as shown in FIG. 19B, the calibration gauge 2 for the comparative measurement device of FIG. 19A is rotated by 180 ° on the stage of the comparative measurement device, and similarly to the measurement procedure in FIG. The diameter and the six distances (D1 to D6) after the rotation in FIG. 13 described above are calculated.

  Further, the fourth comparative measurement difference value at each position (−111 mm, −71 mm, −36 mm, 35 mm, 70 mm, 110 mm) of the 135 ° -315 ° line by the same method as the measurement procedure in FIGS. 16A and 16B described above. Respectively. The difference between the fourth comparison measurement difference value and the calibration value (difference value) is calculated. As a result, measurement errors of the comparative measuring machine at each position (-111 mm, -71 mm, -36 mm, 35 mm, 70 mm, 110 mm) of the 135-315 line are obtained.

  FIG. 20 shows a measurement result obtained by measuring the calibration gauge 2 for a comparative measuring instrument arranged at the 135 ° -315 ° line by the above procedure. FIG. 20 is a graph in which the horizontal axis indicates each position from the origin (center), and the vertical axis indicates the measurement error (mm) of the comparative measuring instrument. Also in the example of the second embodiment, the comparative measuring device ensures the accuracy such that the measurement error becomes ± 0.002 mm (2 μm) or less when the measured object is displaced by 1 mm from the reference position of the stage. (Accuracy guaranteed range in FIG. 20).

  In FIG. 20, the origin (center) of the calibration gauge 2 for the comparative measuring instrument is “offset” in which the origin is shifted by about 0.9 mm from the rotation center of the holding unit 34 of the table 30. Are shown.

  As shown in FIG. 20, in the data (□) without “offset”, the measurement error is within the accuracy assurance range (± 0.002 mm) of the comparative measuring device at all positions from the origin (center). Therefore, when the calibration gauge 2 for a comparative measuring instrument is installed on the table 30 without offset, it can be understood that the accuracy of the comparative measuring instrument is within the guaranteed range at all measurement points along the 135 ° -315 ° line.

  On the other hand, in the data (○) with “offset”, the positions of −111 mm, −71 mm, and 110 mm from the origin are out of the accuracy guarantee range (± 0.002 mm) of the comparative measuring instrument. It is considered that the accuracy was out of the accuracy range because the positional deviation was increased by the amount of the offset and the measurement conditions became strict.

  By setting the origin of the calibration gauge 2 for the comparative measuring device to coincide with the rotation center of the holding portion 34 of the table 30, the condition in which the predetermined positional deviation has occurred can be reproduced, and the measurement error of the comparative measuring device main body can be accurately determined. Can be measured.

  FIG. 21 shows the result of measuring the calibration gauge 2 for the comparative measuring instrument arranged on the 45 ° -225 ° line by the above procedure and confirming the influence of the temperature change. The vertical and horizontal axes in FIG. 21 are the same as those in FIG. FIG. 21 shows data when there is “temperature drift” where the temperature changes by about 2 ° C. around 180 ° rotation during the measurement, and when there is “no temperature drift” where the temperature does not change during the measurement.

  As shown in FIG. 21, in the data (□) with “no temperature drift” on the 45 ° -225 ° line, the measurement error is in the accuracy assurance range (± 0.002 mm) of the comparative measuring device at all positions from the origin. Is in. Also, in the data (）) with “temperature drift” on the 45 ° -225 ° line, the measurement error is within the accuracy assurance range (± 0.002 mm) of the comparative measuring machine at all positions from the origin. .

  Therefore, it can be understood that the accuracy of the comparison measuring machine is within the guaranteed range at all the measurement points on the 45 ° -225 ° line regardless of “with temperature drift” and “without temperature drift”. From the above results, since the gauge body 20 of the calibration gauge 2 for a comparative measuring instrument of the second embodiment is formed of ultra-low thermal expansion ceramics, even if the temperature changes near room temperature during the measurement, the measurement error is stabilized. It was confirmed that measurement was possible.

  As described above, in the calibration gauge 2 for a comparative measuring instrument according to the second embodiment, as described with reference to FIG. 12, the gauge body 20 is provided with the seven opening holes (H1 to H7). The third opening H3, the second opening H2, and the first opening H1 are arranged on the right side of the fourth opening H4 arranged at the center position, and the fifth opening H5, the fifth opening H5 are arranged on the left of the fourth opening H7. Six opening holes H6 and seventh opening holes H7 are arranged. The distance D1 between the center of the fourth opening H4 and the center of the third opening H3 and the distance D2 between the center of the fourth opening H4 and the center of the fifth opening H5 are different by about 1 mm. .

  For this reason, as described with reference to FIG. 13, when the calibration gauge 2 for the comparative measuring instrument in FIG. 12 is rotated by 180 °, the first to third opening holes (H1 to H3) whose distances from the fourth opening hole H4 are different from each other. H3) and the arrangement of the fifth to seventh opening holes (H5 to H7) are interchanged, and a state where a pseudo displacement has occurred is obtained.

  In order to confirm the measurement error of the comparative measuring instrument using the calibration gauge 2 for the comparative measuring instrument of the second embodiment, as described with reference to FIGS. 16A and 16B described above, the position of “−111 mm” in FIG. As an example, first, the distance D6 in FIG. 12 is calculated by the comparative measurement device. Further, after rotating the calibration gauge 2 for the comparative measuring instrument of FIG. 12 by 180 °, the distance D5 of FIG. 13 is calculated by the comparative measuring instrument. Further, a difference between the distance D6 in FIG. 12 and the distance D5 in FIG. 13 is calculated to obtain a comparative measurement difference value.

  Then, by calculating the difference between the comparison measurement difference value and the calibration value (difference value), the deviation amount of the comparison measurement at the position of “−111 mm” can be obtained. By repeating this measurement procedure at each position of the four measurement lines described above, it is possible to obtain a measurement error due to a positional shift at each position of the four measurement lines in the measurable range of the stage of the comparative measuring device. .

  As described above, the method for calibrating the comparative measuring instrument according to the second embodiment includes the steps of measuring the distance between a plurality of measurement marks, providing a predetermined displacement to the gauge body 20, Measuring the distance between the measurement marks, and comparing the difference between the distance between the plurality of measurement marks before and after the displacement is applied and the calibration value.

  The calibration gauge 2 for a comparative measuring instrument of the second embodiment uses, as the gauge body 20, ultra-low-thermal-expansion ceramics having a thermal expansion coefficient of almost zero near room temperature. For this reason, since the gauge body 20 does not expand due to heat even if the temperature changes during measurement, a measurement error can be obtained with higher accuracy than when the gauge body 10 made of metal or the like is used.

  Further, the calibration gauge 2 for a comparative measuring instrument according to the second embodiment is compact and easy to handle because the strip-shaped gauge body 20 is used.

  In FIGS. 12 and 13 described above, the calibration gauge 2 for the comparative measuring instrument is rotated by 180 ° and the positions of the opening holes whose distances from the origin are different from each other are changed, thereby causing a pseudo displacement. ing. In addition to this method, as described with reference to FIG. 14 described above, the table 30 including the holding unit 34 that can move in the X direction and the Y direction may be provided on the stage of the comparative measuring instrument.

  In this case, the first comparative measurement is performed on the calibration gauge 2 for the comparative measuring device arranged on the table 30 on the stage of the comparative measuring device in FIG. 16A described above. Next, without rotating the calibration gauge 2 for the comparative measuring instrument, the calibration gauge 2 for the comparative measuring instrument is moved by the movement of the holding portion 34 of the table 30 so as to have a predetermined displacement amount in the X direction and the Y direction. After the displacement, a second comparative measurement is performed.

  Further, in FIG. 12 described above, the first to seventh opening holes (H1 to H7) are formed in the gauge body 20 as measurement marks, but instead of the opening holes, a convex portion is used to form the gauge body 20. Convex portions and concave portions may be alternately arranged on the surface. As the projection, for example, a block such as a sphere or a rectangular parallelepiped is used. Based on measuring the distance between the protrusions arranged on the gauge main body 20 in the measurement procedure as described above, the measurement error of the comparative measurement device can be similarly obtained.

  Alternatively, in FIG. 12 described above, the distance D1 between the center of the fourth opening H4 and the center of the third opening H3 arranged at the center position, and the center of the fourth opening H4 and the center of the fifth opening H5. May be set to be equal to each other so that the diameter of the opening H3 is different from the diameter of the opening H5.

  The same relationship is set for the second opening H2 and the sixth opening H6, and the first opening H1 and the seventh opening H7, which are arranged substantially symmetrically with respect to the fourth opening H4. In the calibration gauge for a comparative measuring instrument according to this aspect, when rotated by 180 °, the opening holes at each position are replaced with opening holes having different diameters, so that a state where a pseudo displacement has occurred.

  In the measurement procedure in this embodiment, the measurement value of the diameter HD of the fifth opening H5 before the rotation of FIG. 12 and the third opening after the rotation of FIG. The difference between the measured value of the diameter HD of H3 and the measured value is calculated to obtain a comparative measurement difference value. Then, by calculating the difference between the comparison measurement difference value and the calibration value, a measurement error can be obtained.

  The calibration gauge 2 and the calibration method for the comparative measuring machine of the second embodiment can be applied to a contact or non-contact comparative measuring machine and a machine tool using the comparative measurement.

1, 1a, 2 Calibration gauge for comparative measuring instrument 5 Sphere with shaft 10, 20 Gauge body 10a Mounting hole 12 Sphere 12a White sphere 12b Black sphere 14 Shaft portion 14a Small diameter portion 14b Large diameter portion 16, 40 Support base 30 Table 32 Table body 34 Holding section 36 Holding section 38 Rotary knob 42 Horizontal plate 44 Inclined plate 46 Support columns D1 to D6 Distance H1 First opening H2 Second opening H3 Third opening H4 Fourth opening H5 Fifth opening H6 Sixth opening hole H7 Seventh opening hole P White sphere at the center of gauge body

Claims (9)

A table main body, a calibration gauge for a comparative measuring machine attached to the holding part of the table having a holding part movably provided in the table body,
The gauge body,
A plurality of measurement marks provided on the gauge body,
A calibration gauge for a comparative measuring instrument, comprising: a calibration value of at least one of a size of the plurality of measurement marks and a distance between the measurement marks. The plurality of measurement marks include a first mark, and a second mark and a third mark provided substantially symmetrically about the first mark,
The calibration gauge according to claim 1, wherein a distance between the first mark and the second mark is different from a distance between the first mark and the third mark. The plurality of measurement marks include a first mark, and a second mark and a third mark provided substantially symmetrically about the first mark,
The calibration gauge according to claim 1, wherein the second mark and the third mark have different sizes.   4. The calibration gauge according to claim 2, wherein the holding unit is rotatable about the first mark with respect to the table body. 5.   The calibration gauge according to any one of claims 1 to 4, further comprising a support table that supports the table while being inclined in a thickness direction of the gauge body.   The calibration gauge according to any one of claims 1 to 5, wherein the plurality of measurement marks are holes arranged in a line in the gauge body and penetrating in the thickness direction of the gauge body. .   The calibration for a comparative measuring instrument according to any one of claims 1 to 5, wherein the plurality of measurement marks are spheres radially arranged on the gauge body and provided so as to protrude from a surface of the gauge body. gauge. The gauge body,
A plurality of measurement marks provided on the gauge body,
A table for giving a predetermined displacement to the gauge body;
Using a calibration gauge for a comparative measuring device comprising a calibration value of at least one of the size of the plurality of measurement marks and the distance between the measurement marks,
Measuring the size of the plurality of measurement marks or the distance between the measurement marks,
Giving a predetermined displacement to the gauge body;
After giving the predetermined displacement, measuring the size of the plurality of measurement marks or the distance between the measurement marks,
Comparing the calibration value with the difference between the size of the plurality of measurement marks or the distance between the measurement marks before and after the application of the predetermined displacement and the calibration value.   9. The method according to claim 8, wherein the step of applying the predetermined displacement rotates the gauge body.

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