JP2019174169A - Three-dimensional gauge and three-dimensional position error measurement method of machine - Google Patents

Abstract

To provide a three-dimensional gauge for measuring a three-dimensional position error using a machine capable of changing an installation position with high reproducibility in order to easily enable direct measurement of the three-dimensional position error by the machine using the three-dimensional gauge.SOLUTION: A three-dimensional gauge 10 as a reference for three-dimensional position measurement includes: a base plate 22 as the base; a ball plate 12 in which a plurality of measuring balls 14 to be measured are mounted on the upper surface; and raising members 28, 30 for setting the distance between the base plate and the base plate to at least two types of lengths while ensuring reproductivity.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a three-dimensional gauge for measuring and calibrating a position in a three-dimensional space of a machine such as a machine tool, a coordinate measuring machine, or a robot, and a three-dimensional position error measuring method using the three-dimensional gauge.

  As a method of calibrating the three-dimensional position measuring machine, for example, a reference device such as a ball plate manufactured by Retter or an artifact may be used. Retter's ball plate is a two-dimensional gauge with square spheres arranged in a plane. It is impossible to three-dimensionally arrange reference spheres in a three-dimensional space because a sphere located above prevents the measurement of a sphere located below. For use in 3D position measurement, place the ball plate on the XZ plane and the YZ plane and measure it on the front and back of the ball plate, place it on the XY plane at low and high positions, and measure the upper surface of the ball plate, etc. In many cases, a method of estimating the total error is taken from the result of the above.

  The invention of Patent Document 1 describes a two-dimensional lattice calibration apparatus that calibrates two-dimensional coordinate values with high accuracy without turning the artifacts upside down.

JP 2008-292259 A

  However, since the invention of Patent Document 1 is a calibration device for calibrating two-dimensional coordinate values, in order to measure a three-dimensional position error, an artifact such as a ball plate is measured by a measurement system to be calibrated. It must be accurately positioned independently of the measurement results. In particular, in the invention of Patent Document 1, when the position of the ball plate is changed, it is impossible to accurately grasp where the ball plate has moved from the initial position or how the posture has changed. There is a problem that the spheres that become can not be squarely arranged in the three-dimensional direction.

  The present invention has a technical problem to solve such problems of the prior art, and the three-dimensional position of a machine such as a machine tool, a coordinate measuring machine, or a robot capable of changing the installation position with high reproducibility. The object is to provide a three-dimensional gauge for measuring errors. Another object of the present invention is to provide a method capable of measuring a three-dimensional position error of a machine with high repetitive accuracy regardless of the skill level of an operator using the three-dimensional gauge.

  In order to achieve the above-described object, according to the present invention, in a three-dimensional gauge serving as a reference for three-dimensional position measurement, a base plate serving as a base, and a plurality of measurement balls placed on the base plate and to be measured And a positioning structure for setting the height of a plurality of measurement balls of the ball plate mounted on the base plate to at least two kinds of heights while ensuring reproducibility. Former gauge is provided.

  Further, according to the present invention, a three-dimensional position error between the first element member to which the three-dimensional gauge is attached and the second element member to which the measurement probe is attached relative to the first element member in a three-dimensional direction. In the three-dimensional position error measurement method for a machine having a measurement function for measuring the height of the ball, the measurement sphere of the ball plate placed on the base plate is set to at least two types of height using a measuring machine in advance. And measuring the positions of a plurality of measurement balls of the three-dimensional gauge, respectively, as master positions, and the height of the measurement balls of the three-dimensional gauge attached to the first element member of the machine Is set to the first height, and the positioning structure is set to the first position, and the positions of the plurality of measurement balls of the three-dimensional gauge in the second step are set in front. A third step of measuring with the measurement probe, a fourth step of setting the positioning structure to the second position so that the height of the measurement sphere is set to the second height, and the fourth step A fifth step of measuring the positions of a plurality of measurement balls of the three-dimensional gauge in the step with the measurement probe, and the machine relative to the master position based on the measurement results of the first, third and fifth steps. And a sixth step of determining a three-dimensional position error of the machine.

  The three-dimensional gauge according to the present invention can set the height of the measurement sphere with respect to the base plate to at least two kinds of heights with a reproducibility by the positioning structure, so that the measurement sphere can be installed with high reproducibility. It is possible to change the position. Therefore, if the 3D position error of a machine tool, coordinate measuring machine, robot, etc. is measured using the 3D gauge, the 3D position error of the machine can be measured repeatedly with high accuracy regardless of the skill level of the operator. It becomes possible.

It is a perspective view of the three-dimensional gauge used for the three-dimensional position error measurement of the machine by the 1st Embodiment of this invention. It is a perspective view which shows the lower surface of the ball plate of the three-dimensional gauge of FIG. It is a perspective view which shows the upper surface of the base plate of the three-dimensional gauge of FIG. It is a perspective view which shows the state which mounted the raising ball | bowl on the base plate of FIG. It is a perspective view which shows the state which mounted the raising ball | bowl of a diameter smaller than the raising ball | bowl of FIG. 4 on the baseplate. It is a perspective view which shows the state which mounted the ball plate on the raising ball | bowl on the base plate of FIG. It is a perspective view which shows the other example of the raising ball | bowl. It is a perspective view which shows the upper surface of the base plate of the three-dimensional gauge by the 2nd Embodiment of this invention. It is a perspective view which shows the lower surface of the ball plate mounted in the base plate of FIG. FIG. 10 is a perspective view illustrating a state where the ball plate of FIG. 9 is placed on the base plate of FIG. FIG. 10 is a perspective view showing a state where the ball plate of FIG. 9 is placed on the base plate of FIG.

The first embodiment of the present invention will be described below with reference to FIGS.
The three-dimensional gauge 10 as a reference device or artifact used in the three-dimensional position error measuring method of the machine of the present invention includes a ball plate 12 to which a measuring ball 14 is attached, a coordinate measuring machine (not shown), and a machine tool (see FIG. A base plate 22 as a base to be placed and fixed on a table (first element member) (not shown), and a raised ball 28-1 as a first raising member or a high-position raising member disposed between them. 28-3. The ball plate 12 is a plate-like plate made of a material such as metal or ceramics that is stable over a long period of time and has high rigidity, and is a square steel member in the present embodiment. In the present embodiment, 25 measurement balls 14 are arranged and fixed in an array or a matrix of 5 rows and 5 columns. The measurement sphere 14 and the raised spheres 28-1 to 28-3 are preferably made of a material such as metal or ceramics that is stable and has high rigidity over a long period of time, and can be formed from a ceramic material in this embodiment. A drill hole having a diameter smaller than that of the measurement sphere 14 is formed in advance at a position where the measurement sphere 14 on the upper surface 12a is fixed, and the measurement sphere 14 can be made to be bonded to the ball plate 12 using an adhesive. The first element member may be a work table or table (not shown) on which a work is placed and fixed in order for the robot to perform work.

  A positioning structure is provided on the back surface or the bottom surface 12 b of the ball plate 12 facing the base plate 22. The positioning structure includes a reference positioning structure including three positioning balls 16, an orientation determining structure including a pair of cylindrical members 18, and a height determining structure including a plane 20a. The positioning sphere 16 may be arranged at the apex of the equilateral triangle. Preferably, the recess 17 can be formed around a point obtained by projecting the center of a circle passing through the centers of the three positioning balls 16 onto the lower surface 12 b of the ball plate 12. The recess 17 can be formed from a part of a spherical surface. The positioning sphere 16 can be formed of a ceramic material, and, like the measurement sphere 14, a drill hole for sitting can be formed in advance and adhered to the ball plate 12 using an adhesive. The positioning sphere 16 is not limited to a perfect sphere, and may be any member having a spherical surface capable of supporting the raising member 28-1 at three points, as will be described later.

  The cylindrical member 18 is disposed symmetrically with respect to a straight line passing through the center of a circle passing through the centers of the three positioning balls 16 and extends in parallel. The cylindrical member 18 can be made of a ceramic material, and can be bonded to the ball plate 12 using an adhesive by sitting two grooves formed in advance by an end mill. Moreover, the cylindrical member 18 having the orientation determining structure is not limited to a perfect cylindrical member, and may be a rod-like member having a cylindrical surface that engages with the raising member 28-2 as described later.

  The height determining structure can be formed by forming a rectangular recess 20 in the lower surface 12b of the ball plate 12 and fitting, for example, a blog gauge having a flat surface 20a in the recess 20. The blog gauge can be bonded to the ball plate 12 using an adhesive.

  Like the ball plate 12, the base plate 22 is a plate-shaped steel member made of a material such as metal or ceramics that is stable for a long time and has high rigidity. In this embodiment, the base plate 22 is a square steel member. Three sets of holding balls 24-1 to 24-3, each of which is a set of individual spheres, are fixed. In each set, three spheres are arranged at the vertices of an equilateral triangle. Preferably, the recesses 26-1 to 26-3 can be formed around a point obtained by projecting the center of a circle passing through the centers of the three spheres onto the upper surface 22 a of the base plate 22. The recesses 26-1 to 26-3 can be formed from a part of a spherical surface. The holding balls 24-1 to 24-3 can be formed of a ceramic material in the same manner as the positioning balls 16 of the ball plate 12, and a sliding drill hole is formed in advance and bonded to the base plate 22 using an adhesive. be able to. The holding spheres 24-1 to 24-3 are not limited to perfect spheres, and may be members having a spherical surface that can be engaged with the raising members 28-1 to 28-3 and can be supported at three points.

  In the illustrated embodiment, the raising balls 28-1 to 28-3 are placed on the holding balls 24-1 to 24-3 of the base plate 22, respectively. Thus, each of the raising balls 28-1 to 28-3 is supported at three points by each set of holding balls 24-1 to 24-3, and the center thereof is set to the three holding balls 24-1 to 24-24 of each set. -3 is positioned with respect to the base plate 22 by three holding balls 24-1 to 24-3 of each set so as to be arranged on respective straight lines extending upward from the center of a circle passing through each center of -3. The recesses 26-1 to 26-3 act as spaces for preventing contact between the placed raising balls 28-1 to 28-3 and the upper surface 22 a of the base plate 22.

  At the time of measurement, the base plate 22 is placed and fixed, for example, on a table (not shown) of a machine tool. Preferably, the base plate 22 is fixed so that the base plate 22 does not move with respect to the table by the same fixing method as the fixing method on the measuring machine that gives a reference measurement value.

  After placing the raised balls 28-1 to 28-3 on the holding balls 24-1 to 24-3 of the base plate 22, the ball plate 12 makes the lower surface 12 b face the upper surface 22 a of the base plate 22, and holds the holding balls. It is placed on 24-1 to 24-3. At that time, the raised ball 28-1 engages with the three positioning balls 16 of the ball plate 12, and the raised ball 28-2 engages with both of the pair of cylindrical members 18 of the ball plate 12, thereby raising the raised ball 28-3. The ball plate 12 is positioned with respect to the base plate 22 so as to be in contact with the flat surface 20a. The recess 17 acts as a space for preventing contact between the raised ball 28-1 and the lower surface 12b of the ball plate 12 when the ball plate 12 is placed.

  In order to enable the ball plate 12 to be positioned on the base plate 22 in this way, a straight line extending in parallel with the cylindrical member 18 and passing through the center of a circle passing through the centers of the positioning balls 16 is provided with three holding balls. The positioning sphere 16 so that the straight line connecting the centers of the circles passing through the centers of the positioning spheres of each set of the 24-1 and the three holding spheres 24-2 coincides with the straight line projected on the lower surface 12b of the ball plate 12. The cylindrical member 18 is positioned on the lower surface 12 b of the ball plate 12. Furthermore, the flat surface 20a of the height determining structure is placed on the holding ball 24-3 of the base plate 22 when the ball plate 12 is placed on the raised balls 28-1 to 28-3 on the base plate 22. It arrange | positions at the lower surface 12b of the ball plate 12 so that it may contact | abut to the raised ball | bowl 28-3 made.

  When the ball plate 12 is placed on the base plate 22 as shown in FIG. 1, the center of a circle passing through each center of the positioning sphere 16 of the ball plate 12 and the circle passing through each center of the holding sphere 24-1 of the base plate 22 The center is constrained to maintain a certain distance from the center of the raised sphere 28-1. For this reason, the ball plate 12 is in a state in which only the rotational movement is possible with respect to the base plate 22, and the translational movement is impossible.

  When the positioning sphere 16 of the ball plate 12 is engaged with the raised sphere 28-1 and the pair of cylindrical members 18 are engaged with the raised sphere 28-2, the rotational direction in which the ball plate 12 can move with respect to the base plate 22 is one. Determined in the direction. As a result, the ball plate 12 can only rotate relative to the base plate 22 about the line connecting the centers of the raised balls 28-1 and 28-2. When the flat surface 20a comes into contact with the raised ball 28-3, the ball plate 12 cannot move relative to the base plate 22 and is restrained.

  In this way, as shown in FIG. 1, the three-dimensional gauge 10 has the measurement sphere 14 of the ball plate 12 arranged at the uppermost stage of the three-dimensional gauge 10 and can be accessed from the outside by a measurement probe (not shown) such as a stylus. Thus, it is assembled on the table of the machine tool and fixed to the table. At this time, in this embodiment, the ball plate 12 is at a high position with respect to the base plate 22, and a gap H1 is formed between them.

  Next, a main spindle of a machine tool (not shown), which is a second element member that moves relative to the first element member in a three-dimensional direction and attaches a measurement probe using a tool changer (not shown) of the machine tool. ) Is attached to the tip. The measurement probe may be mounted on the spindle of the machine tool by the machine tool operator. Alternatively, the second element member may be a spindle of a coordinate measuring machine or a robot hand. Next, using the X-axis, Y-axis, and Z-axis feed axes of the machine tool, the measurement probe is moved relative to the three-dimensional gauge 10, and the measurement end of the measurement probe is moved to the surface of each measurement ball 14, for example, The center coordinate of each measurement sphere 14 is obtained by contacting one point near the pole (top point) of each measurement sphere 14 and at least three points about every 180 ° along the equator. When the center coordinates of all the measurement spheres 14 are obtained, the relative positions between the measurement spheres 14 are obtained.

  Next, with the base plate 22 fixed to the table, the ball plate 12 is removed, and the raised spheres 28-1 to 28-3 are raised as the second raised members having different sizes (diameters) or the raised balls 30- as the low position raised members. Replace with 1-30-3 (FIG. 5). Since the raising balls 28-1 to 28-3 and the raising balls 30-1 to 30-3 are held by the three holding balls 24-1 to 24-3, respectively, the size (diameter) of the raising balls is changed. In addition, the center position of the raised sphere is arranged on a straight line that is perpendicular to the plane formed by the centers of the three holding spheres and passes through the center of a circle that passes through the centers of the three holding spheres.

  After the replacement of the raised balls, the ball plate 12 is again placed on the raised balls 30-1 to 30-3 as described above. In this example, the raised spheres 30-1 to 30-3 after replacement have a diameter smaller than the diameter of the raised spheres 28-1 to 28-3 before replacement. Therefore, when the ball plate 12 is placed on the raised balls 30-1 to 30-3, the ball plate 12 is disposed at a low position, and the gap between the ball plate 12 and the base plate 22 is H2 <H1. .

  After the ball plate 12 is placed on the raised spheres 30-1 to 30-3, the center coordinates of each measurement sphere 14 are measured again, and the relative positions between the measurement spheres 14 are measured. The relative positions of the center coordinates of all the measurement balls 14 at the high and low positions thus obtained are measured and priced in advance with a coordinate measuring machine (not shown), and the measurement results on the table of the machine tool By comparing, the feeding device of the machine tool can be calibrated. The center coordinates of the measurement sphere 14 of the three-dimensional gauge 10 can be priced by using a coordinate measuring machine owned by the user of the machine tool or robot to be calibrated or by an external calibration service provider. It can be done using it. The coordinate measuring machine is desirably a machine that is calibrated with a standard device having traceability in which the calibration path of the device used for the calibration is clear. In addition, the calibration service provider has been examined by a certification body such as JCSS and confirmed that it conforms to the requirements of the standards (ISO / IEC 17025) for calibration bodies established by the International Organization for Standardization and the International Electrotechnical Commission. It is desirable to be a certified calibration company.

  In the three-dimensional gauge 10 described above, each of the raised balls 28-1 to 28-3 and 30-1 to 30-3 is positioned on the upper surface 22a of the base plate 22 by the three holding balls 24-1 to 24-3. The Therefore, even if the raising balls have different sizes (diameters), the raising balls placed on the three holding balls 24-1 to 24-3 have three holding balls 24-1 to 24- 3 are arranged on a straight line that is perpendicular to the plane formed by the center of 3 and passes through the center of a circle passing through the center. Therefore, the position of the pole that is the uppermost point of the raising sphere does not change in a plane parallel to the upper surface of the base plate 22 even if it changes in the height direction as the size (diameter) of the raising sphere changes. On the other hand, the ball plate 12 is a raised ball 28 in which a straight line that passes through the center of a circle passing through the center of the ball plate 12 is perpendicular to a plane formed by the centers of the three positioning balls 16 of the ball plate 12. -1 or 30-1 so as to pass through the center of the base plate 22 and set as a reference position.

  The positioning structure provided on the lower surface of the ball plate 12 includes a reference positioning structure (three positioning balls 16) that determines the position of the ball plate 12 with respect to the base plate 22, and an orientation determination that determines the orientation of the ball plate 12 with respect to the base plate 22. It consists of three positioning structures: a structure (two cylindrical members 18) and a height determining structure (plane 20a) that determines the height of the ball plate 12 relative to the base plate 22. That is, (1) one of the raised balls 28-1 to 28-3 or 30-1 to 30-3 on which the three positioning balls 16 are placed on the holding balls 24-1 to 24-3 (the implementation described above) In the form, the reference position of the ball plate 12 relative to the base plate 22 is determined by engaging with the raised balls 28-1 or 30-1), and (2) the remaining two raised balls 28-2, 28-3 or 30. -2, 30-3 (in the above-described embodiment, one of the raised spheres 28-2 or 30-2) is engaged with both of the pair of cylindrical members 18, whereby the orientation of the ball plate 12 with respect to the base plate 22 (ball The rotational position of the ball plate 12 in a plane parallel to the plate 12 is determined, and (3) the remaining raised balls 28-3 or 30-3 are brought into contact with the plane 20a of the ball plate 12. By, so that the inclination of the ball plate 12 is determined with respect to the base plate 22.

  In the present embodiment, the positioning sphere 16 is positioned only with respect to the raised sphere 28-1 or 30-1, and the pair of cylindrical members 18 are positioned only with respect to the raised sphere 28-2 or 30-2. 20a is positioned only with respect to the raised balls 28-3 or 30-3, and there is no or little relevance to positioning between the raised balls. Thus, by dividing the function of the positioning structure provided on the lower surface 12b of the ball plate 12, the ball plate 12 is positioned with respect to the base plate 22 with high reproducibility even if a manufacturing error occurs between the positioning structures. It becomes possible.

  It has been described that the height position of the ball plate 12 with respect to the base plate 22 is determined by the flat surface 20a coming into contact with the raised sphere 28-3 or 30-3. 3 or 30-3, the ball plate 12 is inclined with respect to the base plate 22, that is, the ball plate centered on a straight line passing through the center of the raised balls 28-1, 28-2 or 30-1, 30-2. Twelve rotational positions are determined. As described above, according to the present invention, the function required of the ball plate as a reference device in which the ball plate 12 is positioned with very high reproducibility with respect to the base plate 22 is the state when the pricing is performed. There is no difference from the state installed on the machine to be calibrated. For this reason, it is desirable that the ball plate 12 be arranged in parallel to the base plate 22, but the two need not necessarily be arranged in parallel.

  In the above-described embodiment, the raising member is formed from the raising balls 28-1 to 28-3 or 30-1 to 30-3. However, the present invention is not limited to this, for example, as shown in FIG. The raised member 32 can be used. In short, the raising member may be a member having a spherical surface that can be engaged with the holding balls 24-1 to 24-3 of the base plate 22, the positioning balls 16 of the ball plate 12, the pair of cylindrical members 18, and the flat surface 20a. . The raising member 32 in FIG. 7 has a main body portion 34 having a shape obtained by cutting the upper and lower end portions of a sphere with parallel planes, and an upper and lower cylindrical portion 36a coupled to the cut portion of the main body portion 34. A spherical surface 36b is formed at the end of the cylindrical portion 36a. If the upper and lower spherical surfaces 36b are one spherical surface, the raising member 32 can be regarded as a sphere and may be used upside down.

  In the above-described embodiment, the raising members include the raising balls 28-1 to 28-3 as the first raising member or the high position raising member, and the raising ball 30 as the second raising member or the low position raising member. However, the present invention is not limited to this, and the raising member may include a third raising member or a fourth raising member.

  In the above-described embodiment, it has been described that 25 measurement balls 14 are arranged and fixed in an array or a matrix of 5 rows and 5 columns, but the number of measurement balls 14 is not limited to 25. The above or the following number of measurement balls can be attached to the ball plate 12. Further, the measurement spheres 14 can be arranged concentrically, for example, in addition to the matrix shape. Furthermore, the measurement balls 14 may be randomly arranged on the upper surface 12a of the ball plate 12 as long as each measurement ball can be distinguished from other measurement balls. Further, instead of the measurement sphere, a shape that can be a reference such as a precisely processed hole or a rectangular shape may be arranged.

  Next, a second embodiment of the present invention will be described with reference to FIGS. Members having the same functions as those in the first embodiment are denoted by the same reference numerals. On the upper surface 22a of the base plate 22, a reference positioning structure including three positioning balls 16, an orientation determining structure including a pair of cylindrical members 18, and a height determining structure including a plane 20a are disposed. The difference from the first embodiment is that escape holes 40-1 to 40-3 into which long raising columns 44-1 to 44-3 described later enter are formed. On the lower surface 12b of the ball plate 12, there are 180 degrees of short raised columns 42-1 to 42-3 and long raised columns 44-1 to 44-3 that are in contact with the positioning ball 16, the cylindrical member 18, and the flat surface 20a of the base plate 22. Arranged with a phase difference. The tip of each raising column is formed in a hemispherical surface.

  In FIG. 10, the short raising columns 42-1 to 42-3 are in contact with the positioning ball 16, the cylindrical member 18, and the flat surface 20a, respectively, and the measurement ball 14 disposed on the upper surface 12a of the ball plate 12 is positioned at a low position. Shows the state. At this time, the long raising pillars 44-1 to 44-3 enter into the escape holes 40-1 to 40-3 formed in the base plate 22, respectively. FIG. 11 is a perspective view seen from a direction 180 degrees different from FIG. 10 and shows a state in which the ball plate 12 is placed on the base plate 22 with a phase difference of 180 degrees. At this time, the long raised columns 44-1 to 44-3 are in contact with the positioning ball 16, the cylindrical member 18, and the flat surface 20a, respectively, and the measurement ball 14 is positioned at a high position. Compared to the three-dimensional gauge of the first embodiment, the measuring sphere 14 can be easily positioned at two positions, high and low.

  In the second embodiment, the positioning ball 16, the cylindrical member 18, and the flat surface 20 a are disposed on the upper surface 22 a of the base plate 22, and the raised columns 42-1 to 42-3 and 44-1 to 44 are disposed on the lower surface 12b of the ball plate 12. 3 is disposed, the positioning ball 16, the cylindrical member 18, and the flat surface 20a are disposed on the lower surface 12b of the ball plate 12, and the raised pillars 42-1 to 42-3 and 44-1 to the upper surface 22a of the base plate 22 are disposed. 44-3 may be provided. Further, in place of two types of raised and short raised columns, for example, two ball plates having both short raised columns and different thicknesses are prepared, and the measuring ball 14 is positioned at two height positions with high and low reproducibility. Good. The raising elements described in the claims are the raising balls 28-1 to 28-3, 30-1 to 30-3 of the first embodiment, the raising member 32, and the raising pillar 42-1 of the second embodiment. -42-3 and 44-1 to 44-3, and a thick or thin base plate or ball plate. The positioning structure described in the claims refers to a structure in which these raising elements and holding balls 24-1 to 24-3 are combined with a reference positioning structure, an orientation determining structure, and a height determining structure. Note that the method for measuring the three-dimensional position error of the machine using the three-dimensional gauge of the second embodiment is the same as the method described in the first embodiment, and thus the description thereof is omitted.

10 Three-dimensional gauge 12 Ball plate 14 Measurement ball 16 Positioning ball 18 Cylindrical member 20a Plane 22 Base plate 24-1 to 24-3 Holding ball 28-1 to 28-3 Raised ball 30-1 to 30-3 Raised ball

In order to achieve the above-described object, according to the present invention, in a three-dimensional gauge serving as a reference for three-dimensional position measurement, a base plate serving as a base, and a plurality of measurement balls placed on the base plate and to be measured And a positioning structure for setting the height of a plurality of measurement balls of the ball plate placed on the base plate to at least two kinds of heights while ensuring reproducibility , On either one of the upper surface of the base plate and the lower surface of the ball plate, a reference positioning structure composed of three spherical surfaces, an orientation determining structure composed of two sets of parallel cylindrical surfaces, and a height determining structure composed of a plane 2 having a spherical surface that engages and abuts with the reference positioning structure, the orientation determining structure, and the height determining structure, respectively, between and the other surface. Dimensional gauge and a positioning structure which is disposed a raised element of the height of the class are provided.

Claims (6)

In the 3D gauge that is the standard for 3D position measurement,
A base plate as a base,
A ball plate mounted on the top surface and mounted with a plurality of measurement balls to be measured on the base plate;
A positioning structure for setting the height of the plurality of measurement balls of the ball plate placed on the base plate to at least two kinds of heights while ensuring reproducibility;
A three-dimensional gauge characterized by comprising:   In the positioning structure, three spherical surfaces are disposed on one of the upper surface of the base plate and the lower surface of the ball plate, and one of the three spherical surfaces is in contact with the other surface. A set of positioning spheres, a rod-shaped member composed of a pair of parallel cylindrical surfaces with which the other spherical surface of the three spherical surfaces abuts, and a plane with which the remaining spherical surface of the three spherical surfaces abuts. The three-dimensional gauge according to claim 1, further comprising a raising element that sets the height of the plurality of measurement balls of the ball plate to at least two kinds of heights.   For the raising element, two types of diameters of three spherical surfaces arranged on the one surface are prepared, or two types of height direction positions of three spherical surfaces arranged on the one surface are prepared. The three-dimensional gauge according to claim 2.   The positioning structure includes a set of three on the upper surface of the base plate and a set of three at a position corresponding to the set of three positioning balls, the rod-shaped member, and the plane disposed on the lower surface of the ball plate. A ball is disposed, and the raising elements are at least two heights that are interchangeably interposed between the holding balls of each set and the three positioning balls, the rod-shaped member, and the plane. The three-dimensional gauge according to claim 1, comprising a raised member having dimensions. Between the 1st element member which attaches the three-dimensional gauge of any one of Claims 1-4, and the 2nd element member which moves relatively in a three-dimensional direction with respect to the said 1st element member, and attaches a measurement probe In the three-dimensional position error measurement method of a machine having a measurement function for measuring the three-dimensional position error of
Using a measuring machine in advance, set the height of the measurement sphere of the ball plate placed on the base plate to at least two kinds of heights, respectively measure the position of the plurality of measurement spheres of the three-dimensional gauge, A first step as a master position;
A second step of setting the positioning structure to a first position such that the height of the measuring sphere of the three-dimensional gauge attached to the first element member of the machine is set to a first height; When,
A third step of measuring positions of a plurality of measurement balls of the three-dimensional gauge in the second step with the measurement probe;
A fourth step of setting the positioning structure to the second position such that the height of the measurement sphere is set to the second height;
A fifth step of measuring positions of a plurality of measurement balls of the three-dimensional gauge in the fourth step with the measurement probe;
A sixth step of determining a three-dimensional position error of the machine with respect to the master position based on the measurement results of the first, third and fifth steps;
A method for measuring a three-dimensional position error of a machine.   The said machine is a machine tool, The master position of the said 1st step is the value measured by the coordinate measuring machine which measures the dimension of the workpiece | work processed with the said machine tool, The three-dimensional of the machine of Claim 5 Position error measurement method.

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