JP4491681B2 - Positioning control method and positioning control device for rotary table in machine tool - Google Patents

Description

  The present invention relates to a rotary table positioning control method and a positioning control apparatus in a machine tool such as a machining center.

2. Description of the Related Art Conventionally, in a machine tool, by moving a XY table on which a workpiece is installed by a predetermined distance in the X-axis direction or the Y-axis direction, the X-axis direction or the Y-axis of the workpiece on the XY table is measured by a minute distance measuring device. Measure the inclination of the direction, add and subtract the measured value to the NC movement speed command value for machining to calculate the NC corrected movement speed command value, and correct the NC correction taking this work inclination into account An apparatus is known in which the X-Y table is moved by driving an X-axis drive motor and a Y-axis drive motor based on a moving speed command value to guarantee the positioning accuracy of the workpiece (for example, a patent) Reference 1).
In addition, the table can be moved and positioned in the X-axis direction on the X-axis guide surface of the base, the column can be moved and positioned in the Z-axis direction on the Z-axis guide surface of the base, and swiveling can be indexed on the table In a horizontal machining center in which a rotary table is provided and a workpiece attached to a pallet placed on the rotary table is processed by a tool attached to a spindle of a spindle head provided on the column so as to be movable in the Y-axis direction. The inclination of the table with respect to the X-axis guide surface of the base is obtained, the displacement of the workpiece on the table based on this inclination is calculated in each control axis direction, and the control axis is corrected based on the correction amount corresponding to the displacement. A drive motor is driven to correct the workpiece positioning error (see, for example, Patent Document 2).
JP-A-5-318278 JP 2001-325012 A

However, in the former machine tool, the movement position in the X and Y axis directions of the XY table is simply corrected based on the inclination of the workpiece on the XY table in the horizontal plane. A rotary table that rotates about the B axis is provided on the table, and the workpiece mounted on the rotary table is mounted eccentrically with respect to the B axis, or is inclined with respect to the upper surface of the rotary table. When the workpiece posture changes in a complicated manner due to the turning index of the rotary table, there is a problem that the positioning accuracy of the workpiece cannot be guaranteed with high accuracy.
In the latter type of horizontal machining center, no consideration is given to correcting the displacement of each workpiece mounted on the rotary table in the direction of each control axis based on the inclination of the workpiece with respect to the rotary table surface and the eccentricity from the center of the B axis. Therefore, there is a problem that the positioning accuracy of the workpiece cannot be sufficiently improved as in the former machine tool.

  The present invention has been made in view of the above circumstances, and a rotary table positioning control method and a positioning control device in a machine tool capable of positioning a work mounted on the rotary table in each control axis direction with high accuracy. The purpose is to provide.

The present invention is characterized by the following points in order to solve the above problems.
In other words, the rotary table positioning control method for a machine tool according to claim 1 comprises a rotary table provided on a gantry so as to be capable of turning and indexing about the B axis, and a spindle head supported by a support member, By operating the control shaft driving means, the rotary table is rotated and positioned around the B axis, the rotary table and the spindle head are moved relative to each other in the X, Y, and Z axis directions, and the spindle head A rotary table positioning control method in a machine tool for processing a workpiece fixed to the rotary table by a tool mounted on a spindle,
The amount of eccentricity R of the workpiece from the B axis to the eccentric position, the deviation angle α of the eccentric position from the Z axis, the inclination angle ω of the workpiece with respect to the B axis, and the deviation angle θ of the inclination direction with respect to the Z axis . And an error coefficient including an X-axis component β due to the inclination of the B-axis with respect to the Y-axis and a Z-axis component γ due to the inclination of the B-axis relative to the Y-axis in advance in the error coefficient memory of the NC device,
When the machine coordinate position of the Y axis and the machine coordinate position of the B axis are input from the NC unit to the control axis drive means by the machine coordinate input means , based on the machine coordinate position of the Y and B axes and the error coefficient. X, obtains a correction value for the mechanical coordinate position of Z-axis, X, which is operation command based on the correction value, actuates the control shaft driving means to correct the mechanical coordinate position of Z-axis,
When the correction value to be corrected is changed, the correction value for the current machine coordinate position is stored in the correction value data memory instead of the new correction value.

A rotary table positioning control device in a machine tool according to claim 2 comprises a rotary table provided on a gantry so as to be capable of turning and indexing about a B axis, and a spindle head supported by a support member. By actuating the driving means, the rotary table is rotated and positioned around the B axis, and the rotary table and the spindle head are moved relative to each other in the X, Y, and Z axis directions, so that the spindle head has a spindle. A rotary table positioning control device in a machine tool for processing a workpiece fixed to the rotary table by a mounted tool,
The NC device includes an eccentric amount R of the workpiece from the B-axis to an eccentric position, a deviation angle α of the eccentric position from the Z-axis, a tilt angle ω of the workpiece with respect to the B-axis, and a Z in the tilt direction. An error coefficient including a bias angle θ with respect to the axis, an X-axis component β due to the inclination of the B-axis relative to the Y-axis, and a Z-axis component γ due to the inclination of the B-axis relative to the Y-axis is stored in the error coefficient memory of the NC device in advance. And
When the machine coordinate position of the Y axis and the machine coordinate position of the B axis are input from the NC unit to the control axis drive means by the machine coordinate input means , based on the machine coordinate position of the Y and B axes and the error coefficient. X, calculating means for obtaining a correction value for the mechanical coordinate position of Z-axis, the based on the corrected value X, the control shaft driving means a correction value for correcting the operation command value based on the machine coordinate position of Z-axis output Correction means for
The error coefficient memory stores in advance an X-axis component and a Z-axis component of the inclination of the B-axis with respect to the Y-axis, and adds these axis components to the error coefficient with respect to the machine coordinate positions of the X and Z-axes. A function to obtain machine-specific correction values is provided.
The correction means is characterized in that when the correction value is changed , the correction value for the current machine coordinate position is stored in a correction value data memory instead of the new correction value.

According to the rotary table positioning control method and positioning control apparatus for a machine tool according to claims 1 and 2 of the present invention, there is a displacement in the mounting position of the workpiece with respect to the rotary table, and the workpiece is swung around the B axis. Regardless of whether the workpiece is positioned by turning around or when the workpiece is mounted at an angle with respect to the rotary table, the positioning error in each control axis due to the misalignment or tilt of the workpiece is minimized. Thus, the workpiece and the tool can be relatively accurately positioned to a predetermined processing position.
Even when the B-axis is inclined with respect to the Y-axis due to an assembly error of the rotary table with respect to the gantry, the positioning error in each control axis due to the inclination can be reliably reduced.

Hereinafter, a rotary table positioning control apparatus in a machine tool according to an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a rotary table positioning control apparatus in a machine tool according to a first embodiment of the present invention. A rotary table positioning control device 1 in this machine tool is configured as a part of a function of an NC device that controls a machine tool 2 such as a horizontal machining center.
The machine tool 2 is supported on a bed 3 and is supported on the bed 3 by a table 5 that is moved in the X-axis direction (direction perpendicular to the paper surface in FIG. 1) by an X-axis servo motor 4. A column (support member) 7 that is moved by the Z-axis servomotor 6 in the Z- axis direction (left-right direction in FIG. 1) perpendicular to the X-axis, and the X- and Z-axes supported by the column 7 by the Y-axis servomotor 8. Is positioned at the center of the upper surface of the table 5 by a spindle head 9 that is moved in the Y-axis direction (vertical direction in FIG. 1) perpendicular to the table 5, and a B-axis servo motor 10 supported on the table 5. And a turntable 11 that can turn and index around a B axis perpendicular to the axis.

A workpiece W placed on a pallet (not shown in FIG. 1) is carried in and fixed to the rotary table 11 by an automatic pallet changer or the like (not shown), and the fixation is released. To be carried out. A spindle 12 supported by the spindle head 9 so as to be rotatable about the axis is supported, and the workpiece W on the rotary table 11 is processed by a tool attached to the spindle 12.
Connected to the X, Y, Z, B axis servo motors 4, 8, 6, 10 are X, Y, Z, B axis position control circuits (control axis position control circuits) 13 having servo amplifiers for driving them. The X, Y, Z, B axis position control circuit 13 is based on a movement position signal detected by a position detector such as an encoder provided in each of the axis servo motors 4, 8, 6, 10. Each axis servo motor 4, 8, 6, 10 is feedback-controlled.
The rotary table 11 and the spindle head 9 are relatively moved in the X, Y, and Z axis directions by the servo motors 4, 8, 6, 10 and the X, Y, Z, B axis position control circuit 13. Control shaft driving means is configured to move and rotate the rotary table 11 about the B axis.

The positioning control device 1 has an origin at the position of the machining point of the workpiece W placed on the rotary table 11, that is, the B-axis coordinate axis (machine coordinate axis) and the center (B-axis) of the rotary table 11. Based on the X, Y, and Z coordinate axes (machine coordinate axes) along the Y coordinate axis in the B axis direction, the machine coordinate position Pb of the B axis that commands the machining surface of the workpiece W and the tool mounted on the spindle 12 A machine coordinate position memory 14 that stores the machine coordinate position Py of the Y axis, an error factor that causes an error in machining accuracy of the workpiece W mounted on the upper surface of the rotary table 11, and its magnitude (hereinafter referred to as "error coefficient") the error coefficient data memory (error coefficient memory) 15 for storing a designated), mechanical seat from the machine coordinate position memory 14 reads the machine coordinate position Py of the machine coordinate positions Pb and Y-axis of the B-axis A position input unit 16, the machine coordinate position input means 16 each machine coordinate position Pb which is input from, based on the error coefficient read out from the and Py error coefficient data memory 15, a processing position in the processing surface of the workpiece W Calculation means 17 for calculating correction values δx, δy, and δz for the machine coordinate positions of the commanded X, Y, and Z axes by executing a correction program, and the correction values (new correction values) δx, δy and δz are input via the correction value output means 18, and a new correction value δx is added to the correction value (current correction value) for the current machine coordinate position of the X, Y, and Z axes stored in the correction value data memory 19. , Δy, δz, and a correction means 20 for outputting to the X, Y, Z, B axis position control circuit 13 as a new correction value of the machine coordinate position of the X, Y, Z axis. .

Then, the X, Y, Z, B axis position control circuit 13 is the machine coordinate position (control axis position command value) e of the X, Y, Z axis set by the machining program stored in the main memory of the NC device. Is corrected by the correction value, and the X, Y, Z-axis servomotors 4, 8, and 6 are driven based on the corrected position command value, and a new correction value is stored in the correction value data memory 19 as a current correction value. Instead of memorizing it.
Instead of providing the machine coordinate position memory 14, the machine coordinate position input means 16 directly uses the machine coordinate of the B axis from the control axis position command value set in the machining program stored in the main memory of the NC device. The position Pb and the Y-axis machine coordinate position Py may be read out and input to the calculation means 17.

The error coefficient stored in the error coefficient data memory 15 is specified by an installation error of a pallet to which the work W is attached with respect to the rotary table 11, and is unique to the machine obtained by inspecting and measuring individual machines in advance. Is a constant value.
As shown in FIGS. 2 and 3, the error coefficient is on a straight line (B axis) having an origin on the upper surface of the pallet P at the center position S <b> 1 of the rotary table 11 and perpendicular to the upper surface of the rotary table 11. X, Y, and Z axis machine coordinate axes (in FIG. 2, coordinate axes parallel to the X, Y, and Z axis machine coordinate axes with the center position S2 on the top surface of the pallet P as the origin). , Z as the coordinate axis)
(1) The eccentric amount of the center position S2 of the pallet P (work W) relative to the center position S1 (B axis) on the rotary table 11 (the eccentric amount of the work W from the B axis) R,
(2) An eccentric angle α 2 with respect to the Z coordinate axis of the eccentric direction of the center position S2 of the pallet P (the direction connecting the center positions S1 and S2) k.
(3) The inclination angle of the upper surface of the pallet P with respect to the upper surface (plane including the X and Z coordinate axes) of the rotary table 11, that is, the inclination angle of the axis (pallet central axis) p perpendicular to the pallet upper surface with respect to the B axis (work W Tilt angle with respect to the B-axis) ω,
(4) An angle representing the direction of the tilt direction with respect to the B axis of the workpiece W, that is, a bias angle θ 2 from the Z coordinate axis of the plane f perpendicular to the plane including the pallet central axis p and including the X and Z coordinate axes,
(5) X-axis component β (see FIG. 3) due to the inclination of the B-axis with respect to the Y-axis,
(6) Z-axis component γ due to the inclination of the B-axis with respect to the Y-axis (see FIG. 3)
Is mentioned.

Using the error coefficients R, α, ω, θ, β, and γ , correction of positioning errors that occur in the X, Y, and Z axis directions when the workpiece W mounted on the rotary table 11 via the pallet P is processed. The values δx, δy, δz are
δx = R · sin (α + Pb) + Py · sinω · sin (θ + Pb) + Py · β
δy = Py · sin ² ω≈0
δz = R · cos (α + Pb) + Py · sinω · cos (θ + Pb) + Py · γ
It is calculated by the following equation.
Therefore, when machining the workpiece W, the B-axis machine coordinate position Pb for designating the machining surface of the workpiece W and the Y-axis machine coordinate position Py for designating the height from the top surface of the pallet P are variables. , The positioning error correction values δx, δy, and δz are correction values for the positioning command values of the control axes of the X, Y, and Z axes.

Next, in addition to the operation of the rotary table positioning control device in the machine tool having the above-described configuration, the rotary table positioning method in the machine tool according to the embodiment of the present invention is used to drill a workpiece with a boring tool (cutting tool). An example will be described.
When the machine tool 2 is activated and the pallet P carrying the workpiece W is loaded onto the rotary table 11 and fixed by an automatic pallet changer or the like, a machining program is executed by the NC unit, and the machine The B-axis machine coordinate position Pb for designating the machining surface of the workpiece W stored in the coordinate position memory 14 and the Y-axis machine coordinate position Py for designating the Y-axis position of the boring hole are the machine coordinate position input means. 16 reads and inputs to the calculation means 17. The calculation means 17 starts the correction program, and is inputted from the error coefficient R, α, ω, θ, β, γ read from the error coefficient data memory 15 and the machine coordinate position input means 16. Correction values δx, δy, δz for the machine coordinate position (control axis position command value) of the X, Y, and Z axes from the machine coordinate position Pb of the B axis and the machine coordinate position Py of the Y axis on the basis of the respective arithmetic expressions. Is calculated.

These correction values δx, δy, δz are output to the correction means 20 by the correction value output means 18. On the other hand, if the Y-axis and B-axis machine coordinate positions are not input, the correction values δx, δy, and δz are not changed, and thus the correction values already stored in the correction value data memory 19 are output to the correction means 20. The Correcting means 20, the correction value to correct the value obtained by adding a correction value of the correction value output means 18 or a correction value data memory 19, X specified by the machining program, Y, the operation command based on the machine coordinate position of Z-axis Is output to the X, Y, Z, B axis position control circuit 13 as follows. Thereby, the X, Y, Z, B axis position control circuit 13 corrects the machine coordinate values of the X, Y, Z axes designated (commanded) by the machining program with the correction values , and each axis servo motor 4 , 8 and 6 are operated by feedback control, so that the table 5 (rotary table 11) and the spindle head 9 are relatively moved in the X and Y axis directions, and the spindle 12 is moved to the drilling position on the machining surface of the workpiece W. The boring tool is accurately positioned with reduced positioning errors. After this positioning, the table 5 (rotary table 11) and the column 7 (spindle head 9) are moved relative to each other in the Z-axis direction, and the boring tool of the spindle 12 drills the workpiece W. . In that case, even if the drilling depth of the workpiece W is specified, the positioning error in the processing depth is reduced, and drilling is performed accurately as specified.
Incidentally, Y is specified on the machining program by the correction value, the machine coordinate position of the B-axis is corrected, the new correction value δx calculated by the calculation, .delta.y, .delta.z said on behalf of the current correction value It is stored in the correction value data memory 19 and used when calculating correction values thereafter.

For example, when drilling a machined hole with a small-diameter hole in the middle of the workpiece W, or when the machined hole is long and cannot be machined from only one direction, the machined hole is at the 0-degree position of the B-axis machine coordinate position. When the same machining hole is drilled (reverse machining) at the 180-degree position of the machine coordinate position of the B-axis after the rotary table 11 is reversed, the pallet P (work W If the workpiece W is displaced by δx in the X-axis direction with respect to the B-axis (with an error), the center position of the machining hole when the workpiece W is reversed is only twice the error. The machining hole whose axial center is displaced by 2δx and the machining center whose axis is accurately aligned cannot be machined, but the rotary table positioning control device 1 in the machine tool and Positioning control According to the method, such inconvenience does not occur, and highly accurate drilling can be performed.

Next, a rotary table positioning control device 1A in a machine tool according to a second embodiment of the present invention will be described with reference to FIGS.
The rotary table positioning control device 1A in the machine tool according to this embodiment is configured so that the rotary table positioning control device 1 in the machine tool uses the error data measuring means (not shown) provided separately to the rotary table 11. , The mounting accuracy when the pallet (work W) is mounted is measured, the error coefficients R, α, ω, θ, β, γ are obtained from the measurement results, and these are stored in advance in the error coefficient memory. In contrast, as shown in FIG. 4, an error data measurement unit 21 connected to the error coefficient memory 15 is provided, and the error data measurement unit 21 uses the error data measurement unit 21 to store the rotation table 11. The error coefficients R, α, ω, θ, β, and γ obtained by measuring the mounting accuracy of the pallet are automatically input to the error coefficient memory 15. Since the other configuration is the same as that of the positioning control device 1 for the rotary table, the same components are denoted by the same reference numerals and description thereof will be omitted. In FIG. 5, the machine tool 2 is not shown.

  As shown in FIG. 5, the error data measuring means 21 is fixed at a predetermined position on an automatic measuring device 22 including a touch sensor 22a used on the spindle 12 of the machine tool 2 and a pallet P for mounting a workpiece. And a reference cylinder ruler 23 whose shape has been measured, and error calculation means (not shown) for calculating an error coefficient based on the measurement result of the automatic measuring device 22. The reference cylinder ruler 23 includes a reference cylinder portion 23b integrally formed perpendicularly to the reference plate portion 23a. The axis of the reference cylinder portion 23b coincides with the center of the pallet P and is formed on the upper surface of the pallet P. The reference board 23a is positioned and fixed on the pallet P by positioning plates 24a and 24b so as to be vertical.

  In the rotary table positioning control apparatus 1A in the machine tool according to this embodiment, when the accuracy of attaching the pallet P to the rotary table 11 is measured by the error data measuring means 21, the reference cylindrical ruler 23 is fixed. The automatic pallet P is loaded into the rotary table 11 of the machine tool 2 and fixed by an automatic pallet changer or the like, the B axis (control axis) is positioned at the first B axis position, and then mounted on the spindle 12 for automatic measurement. The touch sensor 22a of the device 22 is brought into contact with the reference cylinder portion 23b of the reference cylinder ruler 23 at two positions Yi1 and Yi2 in the Y-axis direction, and the Y-axis positions Yi1 and Yi2 and the Z-axis corresponding to the Y-axis position. The Z-axis positions Zi1 and Zi2 in the axial direction are measured. These measurement data are collected for a plurality of B-axis positions by turning the rotary table 11 about the B-axis. The error data measurement means 21 calculates the error coefficients R, α, ω, θ, β, γ by the error calculation means (not shown) based on the measurement data by a predetermined calculation formula. Since the specific method can be performed using a conventionally known method, description thereof is omitted.

  According to the rotary table positioning control apparatus 1A and the positioning control method in the machine tool according to this embodiment, the error data measuring means 21 is used to measure the installation error of the pallet P with respect to the rotary table 11 using the machine tool 2. Thus, the error coefficients R, α, ω, θ, β, and γ can be easily obtained and immediately stored in the error coefficient data memory 15, and the shape, size, etc. of the workpiece W can be changed to change the palette. When P is changed, the error coefficient can be updated quickly without using a separate error data measuring means.

Next, a rotary table positioning control device 1B in a machine tool according to a third embodiment of the present invention will be described with reference to FIG.
A rotary table positioning control device 1B in a machine tool according to this embodiment is configured by connecting a work material amount input means 25 to the calculation means 17 of the rotary table positioning control device 1 in the machine tool. Since the other configuration is the same as that of the positioning control device 1 for the rotary table, the same components are denoted by the same reference numerals and description thereof will be omitted. In FIG. 6, the machine tool 2 is not shown.
When the mass of the workpiece W attached to the pallet P is large, the deformation of the machine and the ground changes gently due to the difference in the mass of the workpiece W, so that the installation state of the pallet P with respect to the rotary table 11 changes, A slight change is given to the error coefficients R, α, ω, θ, β, γ. Therefore, with respect to the masses W1, W2, and W3 of a plurality of (for example, three types) workpieces W, correction constants for the error coefficients R, α, ω, θ, β, and γ are measured in advance, and correction is performed according to these correction constants. The error coefficients (R1, α1, ω1, θ1, β1, γ1), (R2, α2, ω2, θ2, β2, γ2), (R3, α3, ω3, θ3, β3, γ3) The data is stored in the error coefficient data memory 15 in correspondence with the masses W1, W2, and W3 of W.

In the rotary table positioning control device 1B in the machine tool according to the present embodiment, when the mass of the workpiece W to be machined is input from the work material amount input means 25 to the calculation means 17, it is stored in the NC apparatus. When machining is executed in accordance with the machining program, error coefficients (R1, α1, ω1, θ1, β1, γ1), (R2, α2, and R2) corresponding to the masses W1, W2, and W3 of the workpiece W input by the computing means 17 (ω2, θ2, β2, γ2), (R3, α3, ω3, θ3, β3, γ3) are selected from the error coefficient data memory 15 and read out to calculate the correction values δx, δy, δz, Based on this, the X, Y, Z, B axis position control circuit 13 is operated via the correcting means 20 and the X, Y, Z axis servo motors 4, 8, 6 are operated. At the machining position It is positioned to Make.

Therefore, according to the positioning control device 1B and the positioning control method for the rotary table in the machine tool according to the present embodiment, when machining a plurality of heavy workpieces W having different weights with the machine tool 2, X specified by the machining program by the correction values δx, δy, δz obtained based on the error coefficients R, α, ω, θ, β, γ corrected by the correction coefficient corresponding to the mass of the workpiece W Since the machine coordinate positions of the Y, Z axes are corrected, the tool positioning error relative to the workpiece W machining position based on the pallet installation error relative to the rotary table 11 can be reduced. Eliminating the influence of pallet installation errors on the turntable 11 based on mass, further increasing the tool positioning accuracy with respect to the workpiece W machining position Can.
The work material amount input means 25 may set the mass of the workpiece W in the machining program and read it. A load cell is installed in the automatic pallet changer, and the pallet P is a rotary table. When being carried into 11, it is good also as what measures the mass of the workpiece | work W with a pallet.

As described above, the positioning control method of the rotary table in the machine tool according to the embodiment includes the rotary table provided on the gantry so as to be capable of turning and indexing around the B axis, and the spindle head supported by the support member, By operating the control shaft driving means by the NC device, the rotary table is rotated and positioned around the B axis, the rotary table and the spindle head are moved relative to each other in the X, Y and Z axis directions, A rotary table positioning control method in a machine tool for processing a workpiece fixed to the rotary table by a tool attached to a spindle of a spindle head,
The amount of eccentricity R of the workpiece from the B axis to the eccentric position, the deviation angle α of the eccentric position from the Z axis, the inclination angle ω of the workpiece with respect to the B axis, and the deviation angle θ of the inclination direction with respect to the Z axis . And an error coefficient including an X-axis component β due to the inclination of the B-axis relative to the Y-axis and a Z-axis component γ due to the inclination of the B-axis relative to the Y-axis are stored in advance in the error coefficient memory of the NC device,
When the machine coordinate position of the Y axis and the machine coordinate position of the B axis are input from the NC unit to the control axis drive means by the machine coordinate position input means , based on the machine coordinate positions of the Y and B axes and the error coefficient. Te X, obtains a correction value for the mechanical coordinate position of Z-axis, X, which is operation command based on the correction value, actuates the control shaft driving means to correct the mechanical coordinate position of Z-axis,
When the correction value to be corrected is changed, the correction value for the current machine coordinate position is stored in the correction value data memory instead of the new correction value.

In addition, the rotary table positioning control device in the machine tool according to the embodiment includes a rotary table provided on the gantry so as to be capable of turning and indexing around the B axis, and a spindle head supported by a support member. By operating the control shaft driving means, the rotary table is rotated and positioned around the B axis, the rotary table and the spindle head are moved relative to each other in the X, Y, and Z axis directions, and the spindle head A rotary table positioning control device in a machine tool for processing a workpiece fixed to the rotary table by a tool mounted on a spindle,
The NC device includes an eccentric amount R of the workpiece from the B-axis to an eccentric position, a deviation angle α of the eccentric position from the Z-axis, a tilt angle ω of the workpiece with respect to the B-axis, and a Z in the tilt direction. An error coefficient including a bias angle θ with respect to the axis, an X-axis component β due to the inclination of the B-axis relative to the Y-axis, and a Z-axis component γ due to the inclination of the B-axis relative to the Y-axis is stored in the error coefficient memory of the NC device in advance. And
When the machine coordinate position of the Y axis and the machine coordinate position of the B axis are input from the NC unit to the control axis drive means by the machine coordinate position input means , based on the machine coordinate positions of the Y and B axes and the error coefficient. Calculating means for obtaining correction values for the machine coordinate positions of the X and Z axes, and correction values for correcting the operation command values based on the machine coordinate positions of the X and Z axes based on the correction values. Correction means for outputting,
The error coefficient memory stores in advance an X-axis component and a Z-axis component of the inclination of the B-axis with respect to the Y-axis, and adds these axis components to the error coefficient with respect to the machine coordinate positions of the X and Z-axes. A function to obtain machine-specific correction values is provided.
The correction means is configured such that when the correction value is changed , the correction value for the current machine coordinate position is stored in the correction value data memory instead of the new correction value.

Therefore, according to the rotary table positioning control method and the positioning control devices 1, 1 </ b> A, 1 </ b> B in the machine tool according to the embodiment, there is a displacement in the mounting position of the workpiece W with respect to the rotary table 11, and the workpiece W is Even when positioning is performed by swinging around the B axis, or when the workpiece W is attached to the rotary table 11 in an inclined manner, X, Y, Z due to the positional deviation or inclination thereof. Positioning errors in the control axes of the shafts can be suppressed as small as possible, and the workpiece W and the tool can be relatively accurately positioned to a predetermined machining position.
Further, even when the B axis is inclined with respect to the Y axis due to an assembly error of the rotary table 11 with respect to the table 5, the positioning error in each of the X, Y, and Z control axes due to the inclination is reliably reduced. can do.

In the rotary table positioning control method and the positioning control apparatus 1 in the machine tool according to the above-described embodiment, the workpiece W fixed to the rotary table 11 is indexed to a predetermined machining surface by a B-axis command, and then the rotation is performed. The table 11 and the spindle head 9 are moved relative to each other in accordance with the X and Y axis commands, and the boring tool of the main shaft 12 is positioned at a predetermined drilling position. Thereafter, the boring tool of the main shaft 12 is set according to the Z axis command. Although the example which performs required drilling in the process surface of the said workpiece | work W by moving to a Z-axis direction was shown, this invention is not restricted to such a drilling process, but predetermined | prescribed process surface by the command of B-axis The workpiece W is positioned with the rotary tool of the spindle 12 while the spindle head 9 is relatively moved in the X, Y, and Z axis directions in response to the X, Y, and Z axis commands. It can be similarly applied to a case such as continuous cutting surface.
Moreover, although the example which applied this invention to the horizontal type machining center was shown, this invention is not restricted to this, It can apply also to a vertical type machining center and another machine tool.

It is a block diagram which shows the positioning control apparatus of the rotary table in the machine tool which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the error coefficient showing the installation error of the pallet with respect to a rotary table. It is explanatory drawing showing the inclination with respect to the Y-axis of the B-axis of a rotary table. It is a block diagram which shows the positioning control apparatus of the rotary table in the machine tool which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows an example of an automatic measuring device. It is a block diagram which shows the positioning control apparatus of the rotary table in the machine tool which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

1, 1A, 1B Rotary table positioning control device 2 Machine tool 4, 6, 8, 10 X, Z, Y, B axis servo motor 5 Table (frame)
7 Column (support member)
9 Spindle head 12 Spindle 13 X, Z, Y, B axis position control circuit (Control axis position control circuit)
14 Machine coordinate position memory 15 Error coefficient data memory (error coefficient memory)
16 Machine coordinate position input means 17 Calculation means 18 Correction value output means 19 Correction value data memory 21 Error data measurement means 22 Automatic measuring device 23 Reference cylinder ruler 25 Work substance amount input means

Claims (2)

A rotary table provided on the gantry so as to be able to turn and index around the B axis, and a spindle head supported by a support member, and the control table drive means is operated by the NC device to turn the rotary table around the B axis. Positioning and moving the rotary table and the spindle head relative to each other in the X, Y, and Z axis directions, and machining the workpiece fixed to the rotary table with a tool attached to the spindle of the spindle head. A rotary table positioning control method in a machine,
The amount of eccentricity R of the workpiece from the B axis to the eccentric position, the deviation angle α of the eccentric position from the Z axis, the inclination angle ω of the workpiece with respect to the B axis, and the deviation angle θ of the inclination direction with respect to the Z axis . And an error coefficient including an X-axis component β due to the inclination of the B-axis with respect to the Y-axis and a Z-axis component γ due to the inclination of the B-axis relative to the Y-axis in advance in the error coefficient memory of the NC device,
When the machine coordinate position of the Y axis and the machine coordinate position of the B axis are input from the NC unit to the control axis drive means by the machine coordinate position input means , based on the machine coordinate positions of the Y and B axes and the error coefficient. Te X, obtains a correction value for the mechanical coordinate position of Z-axis, X, which is operation command based on the correction value, actuates the control shaft driving means to correct the mechanical coordinate position of Z-axis,
A rotation table positioning control method in a machine tool, wherein when a correction value to be corrected is changed, a correction value for the current machine coordinate position is stored in a correction value data memory instead of a new correction value. A rotary table provided on the gantry so as to be able to turn and index around the B axis, and a spindle head supported by a support member, and the control table drive means is operated by the NC device to turn the rotary table around the B axis. Positioning and moving the rotary table and the spindle head relative to each other in the X, Y, and Z axis directions, and machining the workpiece fixed to the rotary table with a tool attached to the spindle of the spindle head. A rotary table positioning control device in a machine,
The NC device includes an eccentric amount R of the workpiece from the B-axis to an eccentric position, a deviation angle α of the eccentric position from the Z-axis, a tilt angle ω of the workpiece with respect to the B-axis, and a Z in the tilt direction. An error coefficient including a bias angle θ with respect to the axis, an X-axis component β due to the inclination of the B-axis relative to the Y-axis, and a Z-axis component γ due to the inclination of the B-axis relative to the Y-axis is stored in the error coefficient memory of the NC device in advance. And
When the machine coordinate position of the Y axis and the machine coordinate position of the B axis are input from the NC unit to the control axis drive means by the machine coordinate position input means , based on the machine coordinate positions of the Y and B axes and the error coefficient. Calculating means for obtaining correction values for the machine coordinate positions of the X and Z axes, and correction values for correcting the operation command values based on the machine coordinate positions of the X and Z axes based on the correction values. Correction means for outputting,
The error coefficient memory stores in advance an X-axis component and a Z-axis component of the inclination of the B-axis with respect to the Y-axis, and adds these axis components to the error coefficient with respect to the machine coordinate positions of the X and Z-axes. A function to obtain machine-specific correction values is provided.
The correction means stores a correction value for the current machine coordinate position in a correction value data memory instead of a new correction value when the correction value is changed. Positioning control device.

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