JP2018128328A - Geometric error measurement method for machine tools - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method capable of a geometrical error of an axis of rotation in a state that a main axis is rotated.SOLUTION: A detection device 40 is fixed on a table in a state that an object is put into a non-contact state, and then, a detection position in a three-dimensional space is recognized with an X axis, a Y axis, and a Z axis of the tool T detected by the detection device 40 as a coordinate axis in a state that the tool T is held and rotated by a main axis 8. Next, the main axis and the table are relatively rotated by a predetermined angle around the rotation axis, and after the rotation, the detection position in the three dimensional space of the tool T detected by the detection device 40 is recognized. Then, a geometrical error of the rotation axis relating to a rotary feed device is calculated on the basis of each detection position in the recognized three dimensional space.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of measuring a geometric error of a machine tool, and more particularly to a method of measuring a geometric error related to a rotating shaft of a rotary feeding device that relatively rotates a spindle and a table.

  In recent years, in the field of machine tools, in addition to an X-axis feeding device, a Y-axis feeding device, and a Z-axis feeding device, which are three-axis linear feeding devices orthogonal to each other, the main shaft and the table 2 are relatively rotated. A so-called 5-axis machine tool having two rotary feeding devices has been widely used.

  This five-axis machine tool has an advantage that it can perform complicated machining, but has one aspect that it is difficult to obtain high machining accuracy as compared with a simple straight three-axis machine tool. One of the causes is that a 5-axis machine tool has two rotating shafts in addition to three linear axes, and each shaft is connected in series. It can be considered that errors related to the mounting positions and orientations of the respective shafts are accumulated and become large errors. Further, since the 5-axis machine tool has such a machine structure, it is easily affected by thermal deformation and aging, which is considered to be a factor.

  Therefore, an attempt to measure the feed accuracy of the X-axis feed device, the Y-axis feed device and the Z-axis feed device, the geometric error of each feed shaft, the feed accuracy of each rotary feed device and the geometric error of the rotary shaft on the machine. Has been made. In particular, the measurement of the geometric error of the rotating shaft has been intensively studied recently, and as one of them, a measurement method disclosed in Non-Patent Document 1 below has been proposed. The geometric error means an error in the position and orientation of the axis average line related to each feed axis and rotation axis, and corresponds to “location errors” defined in ISO 230-7: 2015.

  The measurement method disclosed in Non-Patent Document 1 uses a so-called double ball bar having balls at both ends of an extendable bar. Specifically, with one ball side mounted on the table and the other ball side mounted on the spindle of the machine tool, the table is rotated around the rotation axis and synchronized with this to move straight forward. The main shaft is moved in a three-dimensional space by a shaft so that the length of the bar does not change theoretically, and the amount of expansion and contraction of the bar at that time is measured. Then, the geometric error of the rotating shaft is calculated based on the obtained measured value and a predetermined theoretical calculation formula.

  In addition, a method for measuring the geometric error of the rotating shaft using a touch probe for measuring the shape of the workpiece has also been proposed.

Shintaro Tone, Noriyuki Kato, Masaomi Tsutsumi “Improvement of the tool path accuracy of a 5-axis control machining center by measuring and correcting geometric deviations” The Japan Society of Mechanical Engineers (C), Vol. 78, No. 794 (2012-10), page 227 ~ Page 238

  However, the measurement method disclosed in Non-Patent Document 1 described above is performed in a state where a double ball bar is attached to the main shaft, and it is necessary to stop the rotation of the main shaft at the time of measurement. There is a problem that the geometric error in a close state, that is, a state where the main shaft is rotating cannot be measured. The same applies to the measurement method using a touch probe.

  In a machining state in which the main shaft is rotated, it has been conventionally known that a main shaft motor that rotates the main shaft generates heat and the machine tool is thermally deformed by heat from the main shaft motor. Not a little affected by thermal deformation. Therefore, it is considered that there is a large difference that cannot be ignored between the geometric error measured with the main shaft stopped and the geometric error measured with the main shaft rotated.

  For this reason, even if the motion error of the machine tool is corrected based on the conventional measurement method, that is, the geometric error data measured with the spindle stopped, the original geometric error occurring in the machining state can be accurately corrected. Therefore, it cannot be corrected, and therefore, high-precision machining cannot be guaranteed.

  The present invention has been made in view of the above circumstances, and provides a measurement method capable of measuring a geometric error of a rotating shaft in a state in accordance with actual processing, that is, in a state where the main shaft is rotated. For that purpose.

The present invention for solving the above problems is as follows.
A spindle that holds and rotates the tool,
A table to which the workpiece is mounted;
The main shaft and the table are relatively moved in the three orthogonal directions of the Z axis parallel to the axis of the main shaft, the X axis orthogonal to the Z axis, and the Y axis orthogonal to the X axis and the Z axis. A Z-axis feeder, an X-axis feeder and a Y-axis feeder;
At least one rotary feed device for relatively rotating the spindle and the table;
A method for measuring a geometric error of a rotary shaft related to the rotary feed device of a machine tool including the X-axis feed device, the Y-axis feed device, the Z-axis feed device, and a numerical control device that numerically controls the rotary feed device. Because
After fixing a detection device for detecting an object in a non-contact state on the table,
Recognizing the detection position in the three-dimensional space with the X axis, Y axis and Z axis as coordinate axes of the tool detected by the detection device in a state where the tool is held and rotated by the main axis;
Next, the spindle and the table are relatively rotated around the rotation axis by the rotary feeding device at a preset angle, and the detection position of the tool detected in the three-dimensional space after the rotation is detected by the detection device. Recognize
Next, the present invention relates to a geometric error measuring method for a machine tool that calculates a geometric error of the rotating shaft related to the rotary feed device based on each detected position in the recognized three-dimensional space.

  In this geometric error measurement method, first, a detection device that detects an object in a non-contact state is fixed on a table, and then, for example, a tool that is actually used in machining is held on the spindle, and this is used during actual machining. The tool is rotated at a rotational speed, and the detection position of the tool detected by the detection device in a three-dimensional space with the X, Y, and Z axes as coordinate axes is recognized.

  This detected position is a position recognized in the numerical controller based on a position signal input from the X-axis feeder, Y-axis feeder, and Z-axis feeder, for example, in the machine coordinate system. The position when the tool is detected by the detection device. The position signal is, for example, a signal output from an encoder or a linear scale provided in each of the X-axis feeding device, the Y-axis feeding device, and the Z-axis feeding device.

  Next, the rotary feed device relatively rotates the spindle and the table around the rotation axis at a preset angle, and detects the detection position in the three-dimensional space of the tool detected by the detection device after the rotation. recognize.

  Then, based on the recognized detection positions in the three-dimensional space, a geometric error of the rotary shaft related to the rotary feed device is calculated.

  Thus, according to this geometric error measuring method, the geometric error of the rotating shaft in the machine tool in a state where the main shaft is rotated, that is, in a state where the main shaft motor is thermally deformed by the heat of the main shaft motor, as in actual machining. Since it can be measured, it is possible to measure an accurate geometric error in conformity with actual processing. Therefore, it is possible to guarantee highly accurate machining by correcting the motion error of the machine tool based on the accurate geometric error measured in this way.

  In the present invention, as the detection device, a detection device configured to irradiate a laser beam and detect the object when the laser beam is blocked by the object can be used.

  In the present invention, the machine tool includes a C-axis feeding device that rotates the table about the C-axis that is orthogonal to the table upper surface and parallel to the Z-axis, as the rotation feeding device. The first aspect can be taken.

In the machine tool according to the first aspect, when measuring the geometric error of the C-axis, first, the laser beam of the detection device is parallel to the upper surface of the table and parallel to the X-axis or Y-axis. After fixing on the table so that
The tool of the tool detected by the detection device when the table is in a rotational position where the laser beam is parallel to the X axis or the Y axis in a state where the tool is held and rotated by the spindle. Recognize the detection position in the three-dimensional space,
Recognizing a detection position in the three-dimensional space of the tool detected by the detection device at a rotation position obtained by rotating the table by 90 ° in one direction around the C axis by the C-axis feeding device;
While recognizing the detection position in the three-dimensional space of the tool detected by the detection device at a rotation position obtained by further rotating the table by 90 ° in the one direction by the C-axis feeding device,
Recognizing a detection position in the three-dimensional space of the tool detected by the detection device at a rotation position obtained by further rotating the table by 90 ° in the one direction by the C-axis feeding device;
Thereafter, based on the four detected positions in the recognized three-dimensional space, the geometric error of the C axis related to the C axis feeding device is calculated.

  In addition, the machine tool may take a second mode in which the rotary feed device includes a B-axis feed device that rotates the table about the table upper surface and a B-axis parallel to the Y-axis as the rotation axis. it can.

And in the machine tool of this second aspect, when measuring the geometric error of the B axis, first, after fixing the detection device on the table so that the laser beam is parallel to the B axis,
Detection of the tool in the three-dimensional space detected by the detection device when the table is at a rotational position where the upper surface is orthogonal to the Z-axis while the tool is held and rotated by the spindle. While recognizing the position,
The tool detected by the detection device at a rotational position obtained by rotating the table 90 degrees in one direction around the B axis from a rotational position whose upper surface is orthogonal to the Z axis by the B-axis feeding device. Recognizing a detection position in the three-dimensional space;
Next, based on the two detected positions in the recognized three-dimensional space, the geometric error of the B axis related to the B axis feeding device is calculated.

In this case, the B-axis feeding device further rotates the table at a rotational position where the upper surface of the table is rotated 90 ° in a direction opposite to the one direction from the rotational position orthogonal to the Z-axis. Recognizing a detection position in the three-dimensional space of the tool detected by the detection device;
Thereafter, the geometric error of the B-axis relating to the B-axis feeding device may be calculated based on the three detected positions in the recognized three-dimensional space.

  In this way, the geometric error of the B axis can be measured more accurately.

  In addition, the machine tool may adopt a third aspect that includes a B-axis feed device that rotates the main shaft with the B-axis parallel to the table upper surface and the Y-axis as the rotation axis, as the rotary feed device. it can.

And in the machine tool of this third aspect, when measuring the geometric error of the B axis, first, after fixing the detection device on the table so that the laser beam is parallel to the B axis,
The three-dimensional space of the tool detected by the detection device when the spindle is in a rotational position where the axis of the spindle is orthogonal to the table top surface while the spindle is held and rotated. While recognizing the detection position in the
The tool detected by the detection device at a rotational position obtained by rotating the main shaft by 90 ° in one direction around the B axis from a rotational position whose axis is orthogonal to the table top surface by the B-axis feeder. Recognizing a detection position in the three-dimensional space;
Next, based on the two detected positions in the recognized three-dimensional space, the geometric error of the B axis related to the B axis feeding device is calculated.

In this case, further, the B-axis feeding device further rotates the main shaft 90 ° in a direction opposite to the one direction from a rotation position whose axis is orthogonal to the table upper surface. Recognizing a detection position in the three-dimensional space of the tool detected by the detection device;
Thereafter, the geometric error of the B-axis relating to the B-axis feeding device may be calculated based on the three detected positions in the recognized three-dimensional space.

  In this way, the geometric error of the B axis can be measured more accurately.

  In addition, the machine tool, as the rotary feeding device, rotates the table using the D axis that intersects the Y axis and the Z axis at an angle of 45 ° in the Y axis-Z axis plane as the rotation axis. The 4th aspect provided with the feeder can be taken.

And in the machine tool of this fourth aspect, when measuring the geometric error of the D-axis, first, when the table is at a rotational position where the upper surface is parallel to the Z-axis, After fixing the detection device on the table so that the laser beam is in a state perpendicular to the Y axis and the Z axis,
In the three-dimensional space of the tool detected by the detection device when the table is located at a rotational position where the upper surface of the table is orthogonal to the Z-axis while the tool is held and rotated by the spindle. While recognizing the detection position in
The table is rotated by 180 degrees in one direction around the D axis from the rotation position where the upper surface of the table is orthogonal to the Z axis by the D-axis feeding device. At the rotation position where the upper surface is parallel to the Z axis. , Recognizing the detection position in the three-dimensional space of the tool detected by the detection device;
Next, based on the two detected positions in the recognized three-dimensional space, the geometric error of the D axis related to the D axis feeding device is calculated.

In this case, the table is further rotated by 180 degrees in a direction opposite to the one direction from the rotational position where the upper surface is orthogonal to the Z axis by the D-axis feeding device. Recognizing the detection position in the three-dimensional space of the tool detected by the detection device at a rotational position parallel to the axis;
Thereafter, the geometric error of the D-axis related to the D-axis feeding device may be calculated based on the three detected positions in the recognized three-dimensional space.

  In this way, the geometric error of the D axis can be measured more accurately.

  Further, the machine tool, as the rotary feed device, rotates the main shaft with the D axis that intersects the Y axis and the Z axis at an angle of 45 ° in the Y axis-Z axis plane as the rotation axis. A fifth aspect having a feeding device can be taken.

In the machine tool of the fifth aspect, when measuring the geometric error of the D axis, first, the detection device is fixed on the table so that the laser beam is orthogonal to the Y axis and the Z axis. rear,
The three-dimensional of the tool detected by the detection device when the spindle is in a rotational position where the axis of the spindle is parallel to the table top surface while the spindle is held and rotated. While recognizing the detection position in space,
The spindle is rotated by 180 ° in one direction around the D axis from the rotational position where the axis is parallel to the table upper surface by the D-axis feeding device, at the rotational position where the axis is orthogonal to the table upper surface. , Recognizing the detection position in the three-dimensional space of the tool detected by the detection device;
Next, based on the two detected positions in the recognized three-dimensional space, the geometric error of the D axis related to the D axis feeding device is calculated.

In this case, the spindle is further rotated by 180 degrees in a direction opposite to the one direction from the rotational position where the axis is parallel to the table top surface by the D-axis feeding device. Recognizing a detection position in the three-dimensional space of the tool detected by the detection device at a rotation position orthogonal to the table upper surface;
Thereafter, the geometric error of the D-axis related to the D-axis feeding device may be calculated based on the three detected positions in the recognized three-dimensional space.

  In this way, the geometric error of the D axis can be measured more accurately.

  In the present invention, the detection device is disposed at a standby position outside the operation region in which the table and the spindle move relative to each other, and conveys and fixes the detection device from the standby position onto the table when measuring a geometric error. You may do it.

  In the present invention, after setting the ambient temperature in the machining area of the machine tool or the temperature of each component of the machine tool to a temperature that can be regarded as the temperature at the time of machining executed by the machine tool, The geometric error measurement may be performed.

  As described above, according to the present invention, as in actual machining, the geometric error of the rotary shaft is measured in a machine tool in a state where the main shaft is rotated, that is, in a state in which the main shaft motor is thermally deformed by heat. Therefore, it is possible to measure an accurate geometric error in accordance with actual processing. Then, by correcting the motion error of the machine tool based on the accurate geometric error measured in this way, it becomes possible to guarantee highly accurate machining.

It is the perspective view which showed schematic structure of the machine tool in one Embodiment of this invention. It is explanatory drawing for demonstrating the detection apparatus and position detection method which concern on this embodiment. It is explanatory drawing for demonstrating the detection apparatus and position detection method which concern on this embodiment. It is explanatory drawing for demonstrating the detection apparatus and position detection method which concern on this embodiment. In this embodiment, it is explanatory drawing for demonstrating the method to measure the geometric error of the C-axis of a machine tool. In this embodiment, it is explanatory drawing for demonstrating the method to measure the geometric error of the C-axis of a machine tool. In this embodiment, it is explanatory drawing for demonstrating the method to measure the geometric error of the B-axis of a machine tool. In this embodiment, it is explanatory drawing for demonstrating the method to measure the geometric error of the B-axis of a machine tool. It is a graph which shows the geometric error measured by the measuring method concerning this embodiment. It is a graph which shows the geometric error measured by the measuring method concerning this embodiment. It is the front view which showed schematic structure of the other machine tool which can apply this invention. It is the front view which showed schematic structure of the other machine tool which can apply this invention.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[Configuration of machine tool]
First, a schematic configuration of a machine tool as a measurement target will be described. In addition, the said machine tool is only an example, The machine tool which can apply this invention is not limited to this.

  As shown in FIG. 1, the machine tool 1 of this example is a so-called 5-axis machining center, and includes a bed 3, a left side wall part 4 and a right side wall part 5 erected on the bed 3 at a predetermined interval, and the same On the bed 3, a support structure 2 comprising a rear wall portion 6 standing behind the left wall portion 4 and the right wall portion 5, a saddle 7 supported by the support structure 2, a spindle head 8, The rocking member 10, the rotary table 11, and a numerical control device 30 are provided.

  The saddle 7 is disposed on the left side wall 4 and the right side wall 5 so as to straddle them, and is movable along the Y-axis direction which is a horizontal axis in the front-rear direction. The spindle head 8 is provided on the front surface of the saddle 7 and is movable along a horizontal X-axis direction (left-right direction) orthogonal to the Y-axis. A spindle 9 provided along a Z-axis direction (vertical direction) orthogonal to the X-axis and the Y-axis is rotatably held by the spindle head 8, and the spindle 9 extends in the Z-axis direction. It is possible to move along.

  The rocking member 10 is an L-shaped member when viewed from the left side, and its vertical side portion 10a is attached to the front surface of the rear wall portion 6 and can rock around a B axis parallel to the Y axis. It has become. The rotary table 11 is provided on the horizontal side portion 10b of the swing member 10, and is rotatable about a C axis orthogonal to the B axis.

  The saddle 7 is driven by the Y-axis feeding device 21 to move in the Y-axis direction, the spindle head 8 is driven by the X-axis feeding device 20 to move in the X-axis direction, and the spindle 9 is moved to the Z-axis direction. It is driven by the shaft feeder 22 and moves in the Z-axis direction. The swing member 10 is driven by the B-axis feeding device 23 to swing about the B-axis, and the rotary table 11 is driven by the C-axis feeding device 24 to rotate about the C-axis. The main shaft 9 is driven by a main shaft motor (not shown) and rotates about its axis.

  The operations of the X-axis feeding device 20, the Y-axis feeding device 21, the Z-axis feeding device 22, the B-axis feeding device 23, and the C-axis feeding device 24 are controlled by the numerical control device 30, respectively.

  The X-axis feeding device 20, the Y-axis feeding device 21, and the Z-axis feeding device 22 each constitute a linear feed shaft, and these feed axes constitute a machine composed of three orthogonal axes of the X, Y, and Z axes. A three-dimensional space of the coordinate system is formed. The X-axis feeding device 20, the Y-axis feeding device 21, and the Z-axis feeding device 22 are respectively a ball screw, a ball nut screwed to the ball screw, a servo motor that drives the ball screw, and a rotary attached to the servo motor. The numerical controller 30 recognizes the position of the machine coordinate system in each feed axis based on the position signal transmitted from each rotary encoder, and each feed axis, that is, the X-axis feed device 20 is configured. The position control of the Y-axis feeding device 21 and the Z-axis feeding device 22 is performed.

  On the other hand, the B-axis feeding device 23 and the C-axis feeding device 24 are rotary feeding devices each including a servo motor for rotational driving and a rotary encoder attached to the servo motor. Based on the position signal transmitted from each rotary encoder, the rotation position (angular position) around each rotation axis (B axis, C axis) is recognized, and the rotation position of the B axis feeding device 23 and the C axis feeding device 24. To control.

  The machine tool 1 of the present example having the above configuration is driven by the X-axis feeding device 20, the Y-axis feeding device 21, and the Z-axis feeding device 22 under the control of the numerical control device 30, and the machine coordinate system. The main shaft 9 moves within the three-dimensional space and is driven by the B-axis feeding device 23 and the C-axis feeding device 24 to rotate the rotary table 11 around the B-axis and the C-axis.

  Thus, the operation of each of the feeding devices 20, 21, 22, 23, and 24 changes the position, posture, and orientation of the main shaft 9 and the rotary table 11 relatively in the three-dimensional space. Thus, the workpiece provided on the rotary table 11 is processed by the tool mounted on the spindle 9.

  In FIG. 1, the drawing of specific structures of the feeding devices 20, 21, 22, 23, and 24 is omitted for simplification.

[Configuration of detection device]
Next, a schematic configuration of the detection device will be described. As shown in FIG. 2, the detection device 40 of this example has a U-shape in a front view composed of a horizontal base portion 42 and two vertical side portions 42 and 43 provided on the base portion 42 at appropriate intervals. The light emitting element 45 that is built in the main body 41 and the vertical side portion 43 on one side and irradiates the laser light L toward the vertical side portion 44 on the other side. It comprises a light receiving element 46 that receives the irradiated laser light L. The light receiving element 46 detects the detection signal when the received laser beam L is blocked by an object and the amount of received light decreases by a certain amount, that is, when the amount of received light decreases beyond a predetermined threshold, the numerical control device 30. Send to.
[Geometric error measurement method]
Next, with respect to the machine tool 1 described above, geometric errors relating to the B-axis that is the rotation axis of the B-axis feeding device 23 and the C-axis that is the rotation axis of the C-axis feeding device 24 are detected using the detection device 40. A measurement method for measurement will be described.
1. First, accuracy measurement regarding the C axis is performed. In other words, the B-axis angle of the B-axis feeding device 23 is set to 0 °, the upper surface of the rotary table 11 is made horizontal, and the C-axis angle of the C-axis feeding device 24 is set to 0 °. The detection device 40 is attached on the negative side in the Y-axis direction from the C-axis, which is the upper rotation axis. At this time, the detection device 40 is placed on the rotary table so that the laser light L of the detection device 40 is parallel to the X axis and a plane including the B axis and the C axis is positioned between the vertical sides 42 and 43 of the main body 41. 11 (see FIG. 5). A tool T used for machining is mounted on the spindle 9.

Next, under the control of the numerical controller 30, the X-axis feeder 20, the Y-axis feeder 21 and the Z-axis are rotated in a state where the main shaft 9 is rotated at the same rotational speed as the average rotational speed in actual machining. The feeding device 22 is driven to move the tool T slightly above the laser beam L of the detection device 40. At that time, the movement position _{x 1} in the X-axis direction of the lower end center To of the tool T, the origin position of the machine coordinate system _(x 1 = 0). In this example, the numerical control device 30 uses the intersection of the B axis and the C axis recognized in the control as the origin of the machine coordinate system, and the X axis feeding device 20, the Y axis feeding device 21, and the Z axis. It is assumed that the feeding device 22 is controlled.

Next, the Z-axis feeding device 22 is driven to lower the tool T at a low speed. As a result, as shown in FIG. 2, when the tool T blocks the laser light L of the detection device 40 and the amount of light received by the light receiving element 46 exceeds a predetermined threshold value, the numerical control device 30 starts from the light receiving element 46. A detection signal is transmitted. In this example, when the numerical controller 30 receives the detection signal from the light receiving element 46, the numerical controller 30 is based on the position signals transmitted from the X-axis feeder 20, the Y-axis feeder 21, and the Z-axis feeder 22. The position of the lower end center To of the tool T in the machine coordinate system is recorded. Thus, the position z _{1 in} the Z-axis direction of the lower end center To is recorded in the numerical controller 30 by this operation.

  Next, the Y-axis feeding device 21 and the Z-axis feeding device 22 are driven to move the tool T in the Y-axis minus direction and the Z-axis minus direction so that the tool T does not block the laser beam L of the detection device 40. Thus, the laser beam L is positioned on the negative side in the Y-axis direction, and the lower end thereof is positioned on the negative side in the Z-axis direction.

Next, the Y-axis feeding device 21 is driven to move the tool T in the Y-axis plus direction at a low speed. Thereby, as shown in FIG. 3, when the tool T blocks the laser light L of the detection device 40 and the amount of light received by the light receiving element 46 exceeds a predetermined threshold value, the numerical control device 30 starts from the light receiving element 46. Is detected, and the position y _{1 in} the Y-axis direction of the lower end center To at that time is recorded in the numerical controller 30.

As described above, when the rotational position of the C-axis feeding device 24 is 0 °, the positions y ₁ and z ₁ of the lower end center To of the tool T detected by the detection device 40 (see FIG. 4), in other words The position of the detection device 40 is recorded in the numerical control device 30.

Next, the rotary table 11 is rotated 90 ° counterclockwise around the C axis by the C-axis feeding device 24, and the rotary table 11 is rotated to a rotation position of −90 °. Then, the X-axis feeding device 20, the Y-axis feeding device 21, and the Z-axis feeding device 22 are driven to move the tool T slightly above the laser beam L of the detection device 40 in the same manner as described above. At that time, the movement position y ₂ in the Y-axis direction of the lower end center To of the tool T is set as the origin position (y ₂ = 0).

Next, the Z-axis feeding device 22 is driven to lower the tool T at a low speed, and in the same manner as described above, the tool T blocks the laser light L of the detection device 40 and is detected from the light receiving element 46 to the numerical control device 30. The position z ₂ in the Z-axis direction of the lower end center To when the signal is transmitted is recorded in the numerical controller 30.

  Next, the X-axis feeding device 20 and the Z-axis feeding device 22 are driven to move the tool T in the X-axis plus direction and the Z-axis minus direction so that the tool T does not block the laser beam L of the detection device 40. Thus, the laser beam L is positioned on the positive side in the X-axis direction, and the lower end thereof is positioned on the negative side in the Z-axis direction.

Next, the X-axis feeding device 20 is driven to move the tool T in the X-axis minus direction at a low speed. The tool T blocks the laser light L of the detection device 40, and a detection signal is sent from the light receiving element 46 to the numerical control device 30. when it is sent, and records the position x ₂ of the X-axis direction of the lower end center to the numerical controller 30.

As described above, when the rotational position of the C-axis feeding device 24 is −90 °, the position x ₂ , z ₂ of the lower end center To of the tool T detected by the detection device 40, in other words, the detection device 40. Is recorded in the numerical controller 30.

Next, the rotary table 11 is further rotated 90 ° counterclockwise around the C axis by the C-axis feeding device 24, and the rotary table 11 is rotated to a rotation position of −180 °. Then, the X-axis feeding device 20, the Y-axis feeding device 21, and the Z-axis feeding device 22 are driven to move the tool T slightly above the laser beam L of the detection device 40 in the same manner as described above. At that time, the movement position _{x 3} in the X-axis direction of the lower end center To of the tool T and the home position _{(x 3 = x 1 = 0} ).

Next, the Z-axis feeding device 22 is driven to lower the tool T at a low speed, and in the same manner as described above, the tool T blocks the laser light L of the detection device 40 and is detected from the light receiving element 46 to the numerical control device 30. The position z ₃ in the Z-axis direction of the lower end center To when the signal is transmitted is recorded in the numerical controller 30.

  Next, the X-axis feeding device 20 and the Z-axis feeding device 22 are driven to move the tool T in the Y-axis plus direction and the Z-axis minus direction so that the tool T does not block the laser beam L of the detection device 40. Thus, the laser beam L is positioned on the Y axis direction plus side, and the lower end thereof is positioned on the Z axis direction minus side.

Next, the Y-axis feeding device 21 is driven to move the tool T in the Y-axis minus direction at a low speed. The tool T blocks the laser light L of the detection device 40, and a detection signal is sent from the light receiving element 46 to the numerical control device 30. The position y ₃ in the Y-axis direction of the lower end center To at the time of transmission is recorded in the numerical controller 30.

As described above, when the rotational position of the C-axis feeding device 24 is −180 °, the position y ₃ , z ₃ of the lower end center To of the tool T detected by the detection device 40, in other words, the detection device 40. Is recorded in the numerical controller 30.

Next, the rotary table 11 is further rotated 90 ° counterclockwise around the C axis by the C-axis feeding device 24, and the rotary table 11 is rotated to a rotational position of −270 °. Then, the X-axis feeding device 20, the Y-axis feeding device 21, and the Z-axis feeding device 22 are driven to move the tool T slightly above the laser beam L of the detection device 40 in the same manner as described above. At that time, the movement position y ₄ in the Y-axis direction of the lower end center To of the tool T is set as the origin position (y ₄ = y ₂ = 0).

Next, the Z-axis feeding device 22 is driven to lower the tool T at a low speed, and in the same manner as described above, the tool T blocks the laser light L of the detection device 40 and is detected from the light receiving element 46 to the numerical control device 30. The position z ₄ in the Z-axis direction of the lower end center To when the signal is transmitted is recorded in the numerical controller 30.

  Next, the X-axis feeding device 20 and the Z-axis feeding device 22 are driven to move the tool T in the X-axis minus direction and the Z-axis minus direction so that the tool T does not block the laser beam L of the detection device 40. Thus, the laser beam L is positioned on the minus side in the X-axis direction, and its lower end is located on the minus side in the Z-axis direction.

Next, the X-axis feeder 20 is driven to move the tool T in the X-axis plus direction at a low speed. The tool T blocks the laser light L from the detector 40, and a detection signal is sent from the light receiving element 46 to the numerical controller 30. when it is sent, and records the position x ₄ in the X-axis direction of the lower end center to the numerical controller 30.

As described above, when the rotational position of the C-axis feeding device 24 is −270 °, the position x ₄ , z ₄ of the lower end center To of the tool T detected by the detection device 40, in other words, the detection device 40. Is recorded in the numerical controller 30.

Thus, the position of the detection device 40 when the rotational position of the C-axis feeding device 24 is 0 °, −90 °, −180 °, and −270 ° is measured. The geometric error of the C axis can be identified from the position data of the detection device 40 measured in this way. For example, as shown in FIG. 6, the position of the detection device 40 measured when the rotational position of the rotary table 11 is 0 ° is y ₁ , z ₁ , and the rotational position of the rotary table 11 is −180 °. Suppose that the position of the detection device 40 measured at the time is y ₃ , z ₃ , the position of the C axis recognized by the numerical control device 30 for control (indicated by _CR in FIG. 6), and the actual between the position of the C axis (6 indicated by C _a), when the positional error .delta.y ⁰ _BR in the Y-axis direction were present, when ignoring the effect of the slope and B axis C axis, the position error δy ⁰ _BR is expressed by the following equation.
2δy ⁰ _BR = y ₁ + y ₃
Specific geometric error identification for the C axis will be described later.

The operations of the X-axis feeder 20, the Y-axis feeder 21, the Z-axis feeder 22 and the C-axis feeder 24 in this C-axis accuracy measurement are automatically performed under the control of the numerical controller 30. be able to.
2. Next, accuracy measurement regarding the B axis is performed. That is, first, the Z-axis feeding device 22 is driven, and the tool T is moved in the positive direction of the Z-axis, and is retracted to a position that does not interfere with the rotary table 11 and the detection device 40 that rotate about the B-axis.

  Next, the B-axis feeding device 23 is driven while the rotation position of the rotary table 11 is −270 °, and the swinging member 10 and the rotary table 11 are rotated clockwise around the B axis as shown in FIG. Rotate 90 ° and rotate them to the -90 ° rotational position.

  Thereafter, the X-axis feeding device 20 and the Z-axis feeding device 22 are driven, and the position of the Y-axis direction is left as it is, while avoiding interference with the rotary table 11 and the detection device 40, the tool T is detected by the detection device. The laser beam L is moved slightly upward.

Next, the Z-axis feeding device 22 is driven to lower the tool T at a low speed, and in the same manner as described above, the tool T blocks the laser light L of the detection device 40 and is detected from the light receiving element 46 to the numerical control device 30. The position z ₅ in the Z-axis direction of the lower end center To when the signal is transmitted is recorded in the numerical controller 30.

  Next, the X-axis feeding device 20 and the Z-axis feeding device 22 are driven to move the tool T in the X-axis plus direction and the Z-axis minus direction so that the tool T does not block the laser beam L of the detection device 40. Thus, the laser beam L is positioned on the positive side in the X-axis direction, and the lower end thereof is positioned on the negative side in the Z-axis direction.

Next, the X-axis feeding device 20 is driven to move the tool T in the X-axis minus direction at a low speed. The tool T blocks the laser light L of the detection device 40, and a detection signal is sent from the light receiving element 46 to the numerical control device 30. when it is sent, and records the position x ₅ in X-axis direction of the lower end center to the numerical controller 30.

As described above, when the angular position of the B-axis of the B-axis feeding device 23 is −90 °, the position x ₅ , z ₅ of the lower end center To of the tool T detected by the detection device 40, in other words, The position of the detection device 40 is recorded in the numerical control device 30.

  Thus, the position of the detection device 40 when the rotational position of the B-axis feeding device 23 is 0 ° and −90 ° is measured. The geometric error of the B axis can be identified from the position data of the detection device 40 measured in this way. Specific geometric error identification for the B axis will be described later.

The operations of the X-axis feeding device 20, the Y-axis feeding device 21, the Z-axis feeding device 22, and the B-axis feeding device 23 in this B-axis accuracy measurement are automatically performed under the control of the numerical control device 30. be able to.
3. Identification of Geometric Errors Related to B-axis and C-axis In the case of the configuration of the machine tool 1 of this example, assuming that the motion error of the linear feed shaft is small enough to be ignored, the geometric errors related to the B-axis and C-axis are Can be expressed by the following mathematical formulas 1 to 6.
(Formula 1)
y ₁ + y ₃ = 2δy ⁰ _BR −2z ^* ₁ × α ⁰ _CR
(Formula 2)
z ₃ -z ₁ = (y ^* _3- y ^* ₁ ) × α ⁰ _CR
(Formula 3)
x ₂ + x ₄ = 2 (δx ⁰ _BR + δx ⁰ _CB ) + 2z ^* ₂ × β ⁰ _BR
(Formula 4)
z ₄ −z ₂ = (x ^* ₄₋ x ^* ₂ ) × β ⁰ _BR
(Formula 5)
x ₅ −z ^* ₅ × β ⁰ _BR = z ₄ + δx ⁰ _BR −δz ⁰ _BR
(Formula 6)
z ₅ = − (x ₄ −z ^* ₅ × β ^* _BR ) + δx ⁰ _BR + δz ⁰ _BR

In addition, the definition of each parameter of the above formula is as follows.
δx ⁰ _BR : Position error of the B axis in the X axis direction δy ⁰ _BR : Position error of the C axis in the Y axis direction δz ⁰ _BR : Position error of the B axis in the Z axis direction δx ⁰ _CB : X axis of the C axis with respect to the B axis Axis position error α ⁰ _CR : Parallelism of C-axis to Z-axis (around X-axis)
β ⁰ _CR : Parallelism of the C axis to the Z axis (around the Y axis)
Those marked with * mean a nominal value, that is, a value recognized by the numerical control device 30 for its control.

Thus, by solving the above simultaneous equations 1 to 6, the position error δx ⁰ _BR of the B axis in the X axis direction, the position error δy ⁰ _{BR of} the C axis in the Y axis direction, and the Z axis of the B axis Position error δz ⁰ _{BR in} the direction, position error δx ⁰ _CB in the X axis direction of the C axis with respect to the B axis, parallelism of the C axis with respect to the Z axis (around the X axis) α ⁰ _CR , and parallelism of the C axis with respect to the Z axis Six geometric errors of β ⁰ _CR (around Y axis) can be identified.

  As described above, according to the geometric error measuring method of the present example, the spindle 9 is rotated at the same rotational speed as that during actual machining, that is, in a state of being thermally deformed by the heat of the spindle motor (not shown). Since the geometric error of each rotation axis in the machine tool 1, that is, the B axis and the C axis can be measured, an accurate geometric error in accordance with actual machining can be measured. Accordingly, by correcting the motion error of the machine tool 1 on the basis of the accurate geometric error measured in this way, it is possible to ensure high-precision machining.

  Moreover, since it can measure using the tool T used for a process, it is not necessary to prepare a special master tool etc. for a measurement. The detection device 40 may be a general laser measurement device that measures the tool length on the machine, and it is not necessary to prepare a new detection device 40.

  As described above, according to the geometric error measuring method of this example, since a new tool is not particularly prepared, it is possible to measure an accurate geometric error at low cost and considering the thermal deformation of the machine tool 1.

In the machine tool 1 described above, the position error δx ⁰ _BR of the B axis in the X axis direction, the position error δy ⁰ _{BR of} the C axis in the Y axis direction, the position error δz ⁰ _{BR of} the B axis in the Z axis direction, the B axis Position error δx ⁰ _CB in the X-axis direction of the C axis with respect to C, parallelism of the C-axis with respect to the Z-axis (around Y axis) β ⁰ _CR , and parallelism of the C-axis with respect to the Z-axis (around X-axis) α ⁰ _CR An example of the result of measuring two geometric errors is shown in FIGS.

In this example, a straight end mill having a diameter of 10 mm is mounted on the main shaft 9, the main shaft 9 is rotated at a rotational speed of 20000 min ⁻¹ , and the above-described accuracy measurement for the B axis and the C axis is performed about every 30 minutes. Each geometric error was identified from the measured value each time. Then, after this operation is continued for 210 minutes, the spindle 9 is stopped, and when each of the geometric errors is measured in the same manner when about 15 minutes have passed since the stop and about 30 minutes have passed, The main shaft 9 was rotated at a rotational speed of 20000 min ⁻¹ , and each geometric error was measured every 15 minutes up to about 320 minutes.

As shown in FIGS. 9 and 10, the values of the geometric errors δx ⁰ _BR , δy ⁰ _BR , δz ⁰ _BR , δx ⁰ _CB , β ⁰ _CR and α ⁰ _CR change after the spindle 9 starts rotating. And the tendency which tries to return to the original state by stopping the main shaft 9 is shown. Therefore, the geometric errors δx ⁰ _BR , δy ⁰ _BR , δz ⁰ _BR , δx ⁰ _CB , β ⁰ _CR when the machine tool 1 is stopped and when the machine tool 1 is in the machining state. And α ⁰ _CR are different from each other, and it can be understood that an accurate geometric error more suitable for actual machining can be measured by performing the measurement while the main shaft 9 is rotated.

Further, as shown in FIG. 9, the position error δz ⁰ _BR of the B axis in the Z-axis direction fluctuates 80 μm after 210 minutes from the rotation of the main shaft 9, and the position error δz of the B-axis in the Z-axis direction. It can be seen that ⁰ _BR is most greatly affected by the heat caused by the rotation of the main shaft 9. In addition, after the spindle 9 is stopped, the value has changed by about 45 μm in 30 minutes. Even if the spindle 9 is warmed up for a sufficient time, once the spindle 9 is stopped, the machine tool can be stopped in a short time. 1 indicates deformation. Further, not only the displacement in the Z-axis direction but also the position in the X-axis direction of the B-axis was displaced by about 20 μm. Further, as shown in FIG. 10, the change in the error related to the direction of the C-axis was relatively small.

  From the above, the geometric error is measured by causing the machine tool 1 to execute a running operation such as rotating the spindle 9 of the machine tool 1 for a predetermined time, or the ambient temperature in the machining area of the machine tool 1 or It is preferable to carry out after setting the temperature of each component of the machine tool 1 to a temperature that can be regarded as the temperature at the time of machining executed by the machine tool 1.

  As mentioned above, although one Embodiment of this invention was described, the aspect which this invention can take is not limited to this at all.

  For example, in the above example, the accuracy measurement related to the C axis is performed in the order of the rotation position of the rotary table 11 being 0 °, −90 °, −180 °, and −270 °, but is not limited thereto. The measurement may be started from any rotational position, or may be performed in any order. In short, it is only necessary to obtain measured values at four locations.

Further, in the above example, in the accuracy measurement with respect to the B axis, as shown in FIG. 7, the position of the lower end center To of the tool T with the swinging member 10 and the rotary table 11 rotated to the −90 ° rotational position. Although x ₅ and z ₅ are measured, the present invention is not limited to this, and as shown in FIG. 8, the tool is rotated in the state where the swing member 10 and the rotary table 11 are rotated to the 90 ° rotation position. The positions x ₆ and z ₆ of the lower end center To of T may be measured.

Further, the position (x ₄ , z ₄ ) of the lower end center To of the tool T, measured with the swing member 10 and the rotary table 11 rotated to the 0 °, −90 °, and 90 ° rotational positions, respectively. The geometric error may be calculated using x ₅ , z ₅ ) and (x ₆ , z ₆ ). In this way, a more accurate geometric error can be identified.

  Further, in a normal state, the detection device 40 is disposed at a standby position outside the operation region in which the rotary table 11 and the main shaft 9 move relative to each other. It is preferable that the detection device 40 is transported and fixed on the rotary table 11 from the standby position.

In the above example, the rotary table 11 of the machine tool 1 rotates around the B axis. However, the present invention is not limited to this, and the B axis feeding device 23 rotates the spindle head 8 around the B axis. You may be comprised so that it may make. Also in the machine tool having such a configuration, the geometric errors δx ⁰ _BR , δy ⁰ _BR , δz ⁰ _BR , δx ⁰ _CB , β ⁰ _CR and α ⁰ _CR can be identified by the same method as described above.

  Further, the machine tool 1 may be the machine tool 50 shown in FIG. The machine tool 50 is also a so-called 5-axis machining center, and includes a bed 51, a column 52 provided on the bed 51 so as to be movable along an X axis orthogonal to the paper surface, and a vertical Y axis orthogonal to the X axis. A spindle head 8 'held by the column 52 so as to be movable along the column 52, and a saddle 55 provided on the bed 51 that faces the column 52 and is movable along the Z axis perpendicular to the X axis and the Y axis. It has.

  A main shaft 9 'is rotatably held on the main shaft head 8'. The saddle 55 is provided with a support base 56 whose surface facing the column 52 is parallel to the X axis and is an inclined surface that intersects the Y axis and the Z axis at 45 °. Has been. Further, on the inclined surface of the support base 56, the D axis (corresponding to the B axis in the above example) intersecting with the Y axis and the Z axis at an angle of 45 ° within the Y axis-Z axis plane is used as the rotation axis. A rotation base 57 that is rotatable is provided. The rotary base 57 has a horizontal surface at a predetermined angular position, and a rotary table 11 'is provided on this surface.

  The column 52 is driven by the X-axis feeding device 20 ′ to move in the X-axis direction, the spindle head 8 ′ is driven by the Y-axis feeding device 21 ′ to move in the Y-axis direction, and the saddle 55 is It is driven by the Z-axis feeding device 22 ′ to move in the Z-axis direction. The rotary table 11 'is driven by the C-axis feeding device 24' to rotate about the C-axis, and the rotary base 57 is driven by the D-axis feeding device 23 'to rotate about the D-axis, and the main shaft 9'. Is driven by a spindle motor (not shown) and rotates about its axis.

  The X-axis feeding device 20 ′, the Y-axis feeding device 21 ′, the Z-axis feeding device 22 ′, the C-axis feeding device 24 ′, and the D-axis feeding device 23 ′ are operated by the numerical control device 30 ′. Be controlled.

  In this machine tool 50, when the upper surface of the rotary table 11 ′ is in a horizontal state parallel to the Z axis, the detection device is arranged so that the laser light L is in a state orthogonal to the Y axis and the Z axis. After fixing 40 on the rotary table 11 ′, with the tool T mounted on the spindle 9 ′ and rotated, first, the D-axis feeding device 23 ′ is driven to turn the rotary table 11 ′ to the D-axis. Rotate 180 ° around the center. In this state, as indicated by a two-dot chain line in FIG. 11, the upper surface of the rotary table 11 ′ is parallel to the X-axis-Y-axis plane and orthogonal to the Z-axis. This rotational position is the origin, that is, D = 0 °. In this state, the accuracy of the C axis related to the C axis feeding device 24 ′ is measured according to the accuracy measurement related to the C axis described above. Next, the rotary table 11 ′ is rotated by 180 ° around the D axis in one rotation direction or the opposite rotation direction, and rotated to a position where the angular position (rotation position) of the D axis becomes D = 180 °. In accordance with the accuracy measurement related to the B-axis described above, the accuracy of the D-axis related to the D-axis feeding device 23 'is measured.

  And each geometric error is identified using the numerical formulas similar to the above-mentioned Numerical formula 1-Numerical formula 6 based on the measurement data about the obtained C-axis and D-axis. In this machine tool 50, the B axis is replaced with the D axis.

  As a matter of course, the measurement order of the rotational position of D = 0 ° and the rotational position of D = 180 ° in the accuracy measurement of the D-axis may be reverse to the above.

  Also in this machine tool 50, when measuring the accuracy of the D-axis, the geometric error is identified by using both measurement data obtained by rotating 180 degrees in both the one direction and the opposite direction. Anyway.

  Further, the machine tool 1 may be the machine tool 60 shown in FIG. The machine tool 60 is also a so-called 5-axis machining center, and includes a bed 61, a column 62 provided on the bed 61 so as to be movable along the X axis orthogonal to the paper surface, and a vertical Y axis orthogonal to the X axis. Is provided on the bed 61 so as to be movable along the horizontal Z axis perpendicular to the X axis and the Y axis. The rotary table 11 ″ is provided.

  The saddle 63 has, on the turntable 11 ″ side, an inclined surface that is parallel to the X axis and intersects the Y axis and the Z axis at 45 °. There is provided a spindle head 8 ″ that can be rotated about a D axis (corresponding to the B axis in the above example) that intersects the Y axis and the Z axis at an angle of 45 ° in the plane. Further, a spindle 9 "is rotatably held on the spindle head 8".

  The column 62 is driven by the X-axis feed device 20 ″ to move in the X-axis direction, the saddle 63 is driven by the Y-axis feed device 21 ″ to move in the Y-axis direction, and the rotary table 11 ″ is It is driven by the Z-axis feeding device 22 "to move in the Z-axis direction. The rotary table 11 ″ is driven by a C-axis feeder 24 ″ to rotate around the C-axis, and the main shaft 9 ″ is driven by a main-axis motor (not shown) to rotate about its axis. 8 ″ is driven by the D-axis feeding device 23 ″ to rotate around the D-axis, and when it is at a predetermined angular position (rotational position), its axis is vertical and the angular position (180 ° rotated from that position) (Rotational position), the axis is horizontal.

  The X-axis feeding device 20 ″, the Y-axis feeding device 21 ″, the Z-axis feeding device 22 ″, the C-axis feeding device 24 ″ and the D-axis feeding device 23 ″ are operated by the numerical control device 30 ″. Be controlled.

  In this machine tool 60, after the detection device 40 is fixed on the rotary table 11 ″ so that the laser beam L is perpendicular to the Y axis and the Z axis, the tool T is mounted on the main shaft 9 ″ and rotated. At the same time, the D-axis feeding device 23 ″ is driven so that the rotational position where the axis of the main shaft 9 ″ is parallel to the Z-axis is the origin of the D-axis (D = 0 °), and the axis of the main shaft 9 ″ is The spindle head 8 ″ is rotated to a rotational position parallel to the Y axis, that is, a rotational position where D = 180 °. In FIG. 12, this state is indicated by a solid line.

  In this state, the accuracy of the C-axis related to the C-axis feeding device 24 ″ is measured in accordance with the accuracy measurement related to the C-axis described above. Next, the spindle head 8 ″ is rotated around the D-axis on one side. Rotate 180 ° in the direction of rotation or the opposite direction to rotate the D axis to a position where D = 0 °, and according to the accuracy measurement related to the B axis described above, the D axis feeding device 23 ” Measure the accuracy of the D-axis.

  And each geometric error is identified using the numerical formulas similar to the above-mentioned Numerical formula 1-Numerical formula 6 based on the measurement data about the obtained C-axis and D-axis. In this machine tool 60, the B axis is replaced with the D axis.

  As a matter of course, the measurement order of the rotational position of D = 0 ° and the rotational position of D = 180 ° in the accuracy measurement of the D-axis may be reverse to the above.

  Also in this machine tool 60, when measuring the accuracy of the D-axis, the geometric error is identified by using both measurement data obtained by rotating 180 degrees in both the one direction and the opposite direction. Anyway.

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Support structure 3 Bed 4 Left side wall part 5 Right side wall part 6 Rear wall part 7 Saddle 8 Spindle head 9 Spindle 10 Oscillating member 20 X-axis feed device 21 Y-axis feed device 22 Z-axis feed device 23 B-axis Feed device 24 C-axis feed device 30 Numerical control device 40 Detection device 41 Main body 45 Light emitting element 46 Light receiving element

Claims (13)

A spindle that holds and rotates the tool,
A table to which the workpiece is mounted;
The main shaft and the table are relatively moved in the three orthogonal directions of the Z axis parallel to the axis of the main shaft, the X axis orthogonal to the Z axis, and the Y axis orthogonal to the X axis and the Z axis. A Z-axis feeder, an X-axis feeder and a Y-axis feeder;
At least one rotary feed device for relatively rotating the spindle and the table;
A method for measuring a geometric error of a rotary shaft related to the rotary feed device of a machine tool including the X-axis feed device, the Y-axis feed device, the Z-axis feed device, and a numerical control device that numerically controls the rotary feed device. Because
After fixing a detection device for detecting an object in a non-contact state on the table,
Recognizing the detection position in the three-dimensional space with the X axis, Y axis and Z axis as coordinate axes of the tool detected by the detection device in a state where the tool is held and rotated by the main axis;
Next, the spindle and the table are relatively rotated around the rotation axis by the rotary feeding device at a preset angle, and the detection position of the tool detected in the three-dimensional space after the rotation is detected by the detection device. Recognize
Next, a geometric error measurement method for a machine tool, characterized in that a geometric error of the rotary shaft related to the rotary feed device is calculated based on the recognized detection positions in the three-dimensional space. The machine tool includes a C-axis feeding device that rotates the table with the C-axis orthogonal to the upper surface of the table and parallel to the Z-axis as the rotation axis, as the rotary feeding device.
As the detection device, a detection device configured to detect the object when the laser beam is irradiated and blocked by the object is used, and the laser beam is parallel to the upper surface of the table. And fixing on the table so as to be parallel to the X-axis or Y-axis,
The tool of the tool detected by the detection device when the table is in a rotational position where the laser beam is parallel to the X axis or the Y axis in a state where the tool is held and rotated by the spindle. Recognize the detection position in the three-dimensional space,
Recognizing a detection position in the three-dimensional space of the tool detected by the detection device at a rotation position obtained by rotating the table by 90 ° in one direction around the C axis by the C-axis feeding device;
While recognizing the detection position in the three-dimensional space of the tool detected by the detection device at a rotation position obtained by further rotating the table by 90 ° in the one direction by the C-axis feeding device,
Recognizing a detection position in the three-dimensional space of the tool detected by the detection device at a rotation position obtained by further rotating the table by 90 ° in the one direction by the C-axis feeding device;
2. The machine tool according to claim 1, wherein a geometric error of the C-axis related to the C-axis feeding device is calculated based on the four detected positions in the recognized three-dimensional space. Mechanical geometric error measurement method. The machine tool includes, as the rotary feed device, a B-axis feed device that rotates the table with the B-axis parallel to the table upper surface and the Y-axis as the rotary shaft,
As the detection device, a detection device configured to detect the object when the laser beam is irradiated and blocked by the object is used, and the laser beam is parallel to the B axis. After fixing on the table as
Detection of the tool in the three-dimensional space detected by the detection device when the table is at a rotational position where the upper surface is orthogonal to the Z-axis while the tool is held and rotated by the spindle. While recognizing the position,
The tool detected by the detection device at a rotational position obtained by rotating the table 90 degrees in one direction around the B axis from a rotational position whose upper surface is orthogonal to the Z axis by the B-axis feeding device. Recognizing a detection position in the three-dimensional space;
2. The machine tool according to claim 1, wherein a geometric error of the B-axis related to the B-axis feeder is calculated based on the two detected positions in the recognized three-dimensional space. Geometric error measurement method. Further, the B-axis feeding device detects the table at the rotational position obtained by rotating the table by 90 ° in the direction opposite to the one direction from the rotational position whose upper surface is orthogonal to the Z-axis. Recognizing the detection position of the tool in the three-dimensional space,
4. The machine tool according to claim 3, wherein a geometric error of the B-axis related to the B-axis feeder is calculated based on the three detected positions in the recognized three-dimensional space. Mechanical geometric error measurement method. The machine tool includes, as the rotary feeder, a B-axis feeder that rotates the main shaft with the B-axis parallel to the table upper surface and the Y-axis as the rotary axis,
As the detection device, a detection device configured to detect the object when the laser beam is irradiated and blocked by the object is used, and the laser beam is parallel to the B axis. After fixing on the table as
The three-dimensional space of the tool detected by the detection device when the spindle is in a rotational position where the axis of the spindle is orthogonal to the table top surface while the spindle is held and rotated. While recognizing the detection position in the
The tool detected by the detection device at a rotational position obtained by rotating the main shaft by 90 ° in one direction around the B axis from a rotational position whose axis is orthogonal to the table top surface by the B-axis feeder. Recognizing a detection position in the three-dimensional space;
2. The machine tool according to claim 1, wherein a geometric error of the B-axis related to the B-axis feeder is calculated based on the two detected positions in the recognized three-dimensional space. Geometric error measurement method. Further, the B-axis feeding device detects the spindle at a rotational position obtained by rotating the main shaft by 90 ° in a direction opposite to the one direction from a rotational position whose axis is orthogonal to the table top surface. Recognizing the detection position of the tool in the three-dimensional space,
6. The machine tool according to claim 5, wherein thereafter, a geometric error of the B-axis relating to the B-axis feeding device is calculated based on the three detected positions in the recognized three-dimensional space. Mechanical geometric error measurement method. The machine tool is a D-axis feed device that rotates the table as the rotation axis with a D-axis that intersects the Y-axis and the Z-axis at an angle of 45 ° in the Y-axis-Z-axis plane as the rotation axis. With
As the detection device, a detection device configured to detect the object when laser light is irradiated and the laser light is blocked by the object, the table is placed at a rotational position where the upper surface is parallel to the Z axis. After fixing the detection device on the table so that the laser beam is in a state perpendicular to the Y axis and the Z axis when present,
In the three-dimensional space of the tool detected by the detection device when the table is located at a rotational position where the upper surface of the table is orthogonal to the Z-axis while the tool is held and rotated by the spindle. While recognizing the detection position in
The table is rotated by 180 degrees in one direction around the D axis from the rotation position where the upper surface of the table is orthogonal to the Z axis by the D-axis feeding device. At the rotation position where the upper surface is parallel to the Z axis. , Recognizing the detection position in the three-dimensional space of the tool detected by the detection device;
2. The machine tool according to claim 1, wherein a geometric error of the D-axis relating to the D-axis feeding device is calculated based on the two detected positions in the recognized three-dimensional space. Geometric error measurement method. Further, the table is rotated by 180 ° in the direction opposite to the one direction from the rotational position where the upper surface of the table is orthogonal to the Z-axis by the D-axis feeding device, and the upper surface is parallel to the Z-axis. Recognizing the detection position in the three-dimensional space of the tool detected by the detection device,
8. The machine tool according to claim 7, wherein a geometric error of the D-axis relating to the D-axis feeding device is calculated based on the three detected positions in the recognized three-dimensional space. Mechanical geometric error measurement method. The machine tool is a D-axis feed device that rotates the main shaft with the D-axis that intersects the Y-axis and the Z-axis at an angle of 45 ° in the Y-axis / Z-axis plane as the rotation axis. With
As the detection device, a detection device configured to detect the object when the laser beam is irradiated and the laser beam is blocked by the object is used. After fixing on the table to be orthogonal,
The three-dimensional of the tool detected by the detection device when the spindle is in a rotational position where the axis of the spindle is parallel to the table top surface while the spindle is held and rotated. While recognizing the detection position in space,
The spindle is rotated by 180 ° in one direction around the D axis from the rotational position where the axis is parallel to the table upper surface by the D-axis feeding device, at the rotational position where the axis is orthogonal to the table upper surface. , Recognizing the detection position in the three-dimensional space of the tool detected by the detection device;
2. The machine tool according to claim 1, wherein a geometric error of the D-axis relating to the D-axis feeding device is calculated based on the two detected positions in the recognized three-dimensional space. Geometric error measurement method. Further, the spindle is rotated by 180 degrees in a direction opposite to the one direction from the rotational position where the axis is parallel to the table upper surface by the D-axis feeding device, and the axis is orthogonal to the table upper surface. Recognizing the detection position in the three-dimensional space of the tool detected by the detection device,
The machine tool according to claim 9, wherein thereafter, a geometric error of the D-axis relating to the D-axis feeding device is calculated based on the three detected positions in the recognized three-dimensional space. Mechanical geometric error measurement method.   The machine tool geometric error measurement method according to claim 1, wherein the detection position of the tool detected by the detection device is acquired from the numerical control device.   The detection device is disposed at a standby position outside an operation region in which the table and the spindle move relative to each other, and when detecting a geometric error, the detection device is transported from the standby position onto the table and fixed. 12. The geometric error measuring method for a machine tool according to claim 1, wherein the geometric error is measured.   The geometric error is measured after setting the ambient temperature in the machining area of the machine tool or the temperature of each component of the machine tool to a temperature that can be regarded as the temperature at the time of machining executed by the machine tool. 13. The geometric error measuring method for a machine tool according to claim 1, wherein the geometric error is measured.

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