JP3848186B2 - TABLE CONTROL DEVICE, TABLE CONTROL METHOD, TABLE CONTROL PROGRAM, AND COMPUTER-READABLE RECORDING MEDIUM CONTAINING THE TABLE CONTROL PROGRAM - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a table control device in a machine tool capable of multi-axis control having a tilt table and a rotary table arranged on the tilt table.
[0002]
[Prior art]
An example of a machine tool capable of multi-axis control is one in which a tilting table and a rotary table are mounted on a horizontal machining center. The tilt table rotates about the X axis (A axis), and the rotary table arranged on the tilt table rotates about the Y axis (B axis). Then, the workpiece placed on the rotary table is processed by operating the X axis, the Y axis, the Z axis, the A axis, and the B axis. With such a machine tool capable of controlling five axes, it is possible to machine a mold having a complicated shape.
[0003]
Here, FIG. 1 shows a layout of the tilt table and the rotary table. 1A is a plan view, and FIG. 1B is a front view. The rotation shafts 2A and 2B of the tilt table 2 are pivotally supported by the support portions 1A and 1B of the support member 1. The rotary shafts 2A and 2B are rotationally driven via a worm gear by a motor (not shown). Then, the rotary table 3 is disposed on the tilt table 2. The turntable 3 is rotationally driven by a motor (not shown). A pallet 4 is placed on the rotary table 3, and a workpiece 6 is placed on the pallet 4. The tilt table 2 can rotate from about 0 degrees to about 110 degrees when the state of FIG. 1 is set to the reference state (A-axis angle θ = 0).
[0004]
[Problems to be solved by the invention]
However, such a tilt table 2 of a machine tool capable of multi-axis control is generally large in size, and the intervals between the support portions 1A and 1B of the support member 1 are very large. Therefore, it is difficult to process the support portions 1A and 1B coaxially. If the support portions 1A and 1B are processed separately, it becomes difficult to match the centers of the support portions 1A and 1B. That is, as shown in FIG. 8, a shift amount a is generated between the centers of the support portions 1A and 1B. The tilt table 2 attached to the support member 1 is inclined at an angle φ with respect to the X axis. Note that the inclination angle φ shown in FIG. 8 is actually a very small angle.
[0005]
FIG. 5 shows a state when the tilt table 2 is rotated when the tilt table 2 is mounted so as to be inclined with respect to the X-axis. FIG. 5A is a diagram of the pallet 4 viewed from the Y-axis direction when the tilt table 2 is in the reference state (A-axis angle θ = 0). FIG. 5B is a view of the pallet 4 viewed from the Z-axis direction when the tilt table 2 is rotated 90 degrees (A-axis angle θ = 90). As shown in FIG. 5A, in the reference state (A-axis angle θ = 0), the pallet 4 is previously made parallel to the X-axis by using the edge locator (reference surface) 5. . As shown in FIG. 5 (b), when the tilt table 2 mounted at an inclination is rotated, the pallet 4 and the workpiece 6 are inclined by an angle α in the B-axis direction with respect to the X-axis. . Hereinafter, the inclination angle α of the pallet 4 with respect to the X axis is referred to as “B axis deviation angle”. Note that the B-axis deviation angle α shown in FIG. 5B is actually a very small angle.
[0006]
Here, machining by a conventional machine tool capable of multi-axis control is performed in a state in which the tilt table 2 is rotated and fixed at a predetermined angle. Therefore, after the tilt table 2 is fixed, the rotary table 3 can be indexed so that the edge locator (reference surface) 5 is parallel to the X-axis line (B-axis deviation angle α = 0), and then machining can be performed. It was.
[0007]
However, in recent simultaneous multi-axis control machining that performs machining while simultaneously controlling multiple axes, it is required to perform machining while rotating the tilt table 2. In such a case, conventionally, since the B-axis deviation angle α during the rotation of the tilt table 2 has not been removed, the machining accuracy of the workpiece may be reduced.
[0008]
The present invention has been made in view of such circumstances. When simultaneous multi-axis control machining is performed, the influence of the tilt angle φ of the tilt table 2 on the machining accuracy of the workpiece is removed, and the machining accuracy is improved. It is an object of the present invention to provide a table control apparatus capable of improving the performance.
[0009]
[Means for Solving the Problems]
Therefore, the present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, calculates the B-axis deviation angle α corresponding to the rotation angle (A-axis angle) θ of the tilt table, and performs simultaneous multi-axis control. The inventors came up with the idea of correcting the B-axis deviation angle α with a rotary table during machining, and completed the present invention.
[0010]
(Table control device)
That is, the rotary table control means of the table control apparatus of the present invention is characterized by having a deviation angle calculating means and a rotary table correcting means. The table control device includes a tilt table, a tilt table control unit, a rotary table, and a rotary table control unit.
[0011]
Here, the tilt table is rotatably supported by the pair of support portions. The tilt table control means is control means for controlling the rotation of the tilt table relative to the support portion. The rotary table is disposed on the tilt table so as to be rotatable about the normal axis of the tilt table on the tilt table, and a workpiece is placed thereon. The turntable control means is control means for controlling the turntable to rotate with respect to the tilt table. The deviation angle calculation means is a calculation means for calculating the deviation angle (B-axis deviation angle) of the workpiece according to the rotation angle (A-axis angle) of the tilt table. The deviation angle is an inclination angle with respect to a reference around the normal axis of the tilt table on the tilt table that may be generated by rotation of the tilt table. The reference for the deviation angle is a line parallel to the rotation axis (X axis) of the tilt table. The rotation table correction means corrects the deviation angle (B axis deviation angle) of the workpiece by rotating the rotation table according to the rotation angle (A axis angle) of the tilt table when the tilt table is rotated. It is.
[0012]
That is, first, a B-axis deviation angle corresponding to the A-axis angle is calculated in advance for each machine tool. The reason why each machine tool is used is that the tilt angle of the tilt table is generally different for each machine tool. When the machining is actually performed while rotating the tilt table, the rotation can be corrected by rotating the rotary table according to the rotation angle (A-axis angle).
[0013]
As a result, when performing simultaneous multi-axis control machining, specifically, when performing machining while rotating the tilt table, it is possible to remove the influence on the machining accuracy of the workpiece caused by the tilt angle of the tilt table, The machining accuracy of the workpiece can be improved.
[0014]
The deviation angle calculation means may include deviation angle setting means, relational expression setting means, and relational expression deviation angle calculation means. Here, the deviation angle setting means is a setting means for presetting a deviation angle that occurs when the rotation angle of the tilt table is a predetermined rotation angle. The relational expression setting means is a setting means for setting a relational expression obtained by interpolating between predetermined rotation angles based on the set deviation angle. Relational expression deviation angle calculation means is calculation means for calculating the deviation angle based on the relational expression. For example, the deviation angle setting means sets a predetermined rotation angle (A-axis angle) of the tilt table as 0 degrees, 30 degrees, 60 degrees, and 90 degrees, and sets the deviation angle (B-axis deviation angle) that occurs in each case. . Then, the relational expression setting means sets a relational expression in which the A-axis angle is interpolated between 0 degree and 30 degrees. The same is set for other rotation angles. Based on the set relational expression, the B axis deviation angle corresponding to the current A axis angle is calculated.
[0015]
In other words, the B axis deviation angle can be easily calculated in a short time by using the interpolated relational expression.
[0016]
Further, the turntable correction means of the present invention may perform the correction by shifting the origin position of the turntable by a deviation angle. That is, a position obtained by subtracting the B-axis deviation angle from the origin position (B-axis origin position) of the rotary table is set as the B-axis origin position. This can be performed using the origin position shift function of the programmable logic controller (hereinafter referred to as “PLC”).
[0017]
The rotary table control means of the present invention is a control means for controlling the rotation of the rotary table according to the command value of the NC program, and the rotary table correction means uses the subtraction command value obtained by subtracting the deviation angle from the NC program command value. Correction may be performed by using a command value of the program. That is, correction can be performed by changing the command value from the NC program without changing the B-axis origin position. That is, it is not necessary to use an external device such as a PLC.
[0018]
Further, the pair of support portions supporting the tilt table can be applied when the center is shifted in the horizontal direction. When it is displaced in the vertical direction, the tilt angle of the tilt table can be removed by other methods, but the tilt angle of the horizontal direction cannot be removed. That is, even when the centers of the pair of support portions are displaced in the horizontal direction, according to the present invention, the machining accuracy of the workpiece can be reliably improved.
[0019]
(Table control method)
So far, the case where the present invention is considered as an apparatus has been described, but the present invention is not limited to the apparatus. That is, as long as the same function can be realized, a method for executing table control, a program for causing a computer to function, or a computer-readable recording medium on which the program is recorded may be used. May be.
[0020]
That is, the table control method of the present invention is characterized by comprising a deviation angle calculating step and a rotary table correcting step.
[0021]
Here, the step of calculating the shift angle is a step of calculating a shift angle of the workpiece around the normal axis of the tilt table on the tilt table that can be generated by the rotation of the tilt table by the tilt table control means according to the rotation angle of the table. It is. The rotation table correction step is a step of correcting the displacement angle of the workpiece by the rotation of the rotation table according to the rotation angle of the tilt table when the tilt table is rotated.
[0022]
In addition, about the other characteristic part in a table control apparatus, each means of a table control apparatus can be substituted to a step, and it can implement | achieve as a table control method.
[0023]
(Table control program)
The table control program of the present invention is characterized in that a shift angle calculation step and a rotation table correction step are executed by a computer. Here, the deviation angle calculation step and the rotation table correction step are the same as described above.
[0024]
In addition, about the other characteristic part in a table control method, it can implement | achieve as a program for table control which performs each step of a table control method with a computer.
[0025]
(Computer-readable recording medium on which table control program is recorded) The computer-readable recording medium on which the table control program of the present invention is recorded is a computer that performs a shift angle calculation step and a rotary table correction step. It is made to perform. Here, the deviation angle calculation step and the rotation table correction step are the same as described above.
[0026]
In addition, about the other characteristic part in a table control method, it can implement | achieve as a computer-readable recording medium which recorded the program for table control which performs each step of a table control method with a computer.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments.
[0028]
First, a horizontal machining center will be described as an example of a machine tool capable of simultaneous multi-axis control. The horizontal machining center includes a support member 1 that moves in the X-axis direction, a column (not shown) that moves in the Z-direction orthogonal to the X-axis in a horizontal plane, and a Y-axis that is orthogonal to the X-axis and Z-axis on this column. It has a tool head (not shown) that moves in the direction, and a tool (not shown) supported by the tool head. The horizontal machining center further includes a tilt table 2 that can be rotated about the X axis (A axis) on the support member 1, and a rotary table that can be rotated about the normal axis (B axis) on the tilt table 2. 3. Then, the workpiece placed on the rotary table 3 is processed by operating the X axis, Y axis, Z axis, A axis, and B axis. The workpiece 6 has a complicated shape on the surface to be processed, such as a mold. Here, since the arrangement of the tilt table 2 and the rotary table 3 is the same as the conventional one, the description thereof is omitted (shown in FIG. 1) .
[0029]
(First embodiment)
FIG. 2 shows a schematic configuration of the table control apparatus according to the present invention. That is, the table control device includes a tilt table 2, a tilt table drive motor (tilt table control means) 7, a rotary table 3, a rotary table drive motor (rotary table control means) (not shown), and an encoder. 8, a B-axis deviation angle calculation unit (deviation angle calculation unit) 9, and a B-axis origin position shift unit (rotation table correction unit) 10.
[0030]
First, the rotation angle (hereinafter referred to as “A-axis angle”) θ of the tilt table 2 is detected by the encoder 8. Based on the detected A-axis angle θ, a deviation angle (hereinafter referred to as “B-axis deviation angle”) α around the normal axis on the tilt table 2 that can be generated by the rotation of the tilt table 2 is calculated as a B-axis deviation angle. Calculated by the unit 9. The calculation process of the B-axis deviation angle α will be described later. Subsequently, the position (angle) (= β−α) obtained by subtracting the B axis deviation angle α from the currently set B axis origin position (angle) β by the B axis origin position shift unit 10 (PLC or the like) is set to B The axis origin position (angle) is β. The rotation of the rotary table is controlled according to the command value of the NC program with reference to the B-axis origin position β thus shifted.
[0031]
Next, the flow of processing for shifting the B-axis origin position in the B-axis origin position shift unit 10 (PLC or the like) will be described with reference to the flowchart (left side) of FIG. First, it is determined whether or not the A-axis operation command is in an ON state (A-axis operation state) (step S1). The A-axis operation state is a state in which the tilt table is rotated. In the ON state (A-axis operation state) (step S1: Y), the calculation instruction signal for the B-axis deviation angle α is turned on (step S2). Then, the B-axis deviation angle α calculated by the B-axis deviation angle calculation unit 9 (shown in FIG. 2) is read (step S3). Based on the read B-axis deviation angle α, the B-axis origin position is shifted (step S4). And it returns to step S1 and the above-mentioned process is repeated. On the other hand, when it is not in the A-axis operation state, that is, when the tilt table is fixed by hydraulic pressure or the like, the calculation instruction signal for the B-axis deviation angle α is turned off until the A-axis operation state is reached (step S5).
[0032]
Next, the calculation process of the B-axis deviation angle α by the B-axis deviation angle calculation unit 9 (shown in FIG. 2) will be described with reference to the flowchart (right side) of FIG. Based on ON / OFF of the calculation instruction signal of the B-axis deviation angle α by the B-axis origin position shift unit 10 (shown in FIG. 2), the calculation process of the B-axis deviation angle α is performed. Specifically, when the calculation instruction signal for the B-axis deviation angle α is ON (step S11: Y), the current A-axis angle θ detected by the encoder 8 (shown in FIG. 2) is read (step S11). S12). In accordance with the read A-axis angle θ, the B-axis deviation angle α is calculated based on the relationship described later (step S13). The calculated B-axis deviation angle α is written into the B-axis origin position shift unit (shown in FIG. 2) (step S14). And it returns to step S11 and the above-mentioned process is repeated. On the other hand, when the calculation instruction signal for the B-axis deviation angle α is OFF, the calculation process is not performed until this signal is turned ON (step S11: N).
[0033]
Next, the relationship of the B-axis deviation angle α with respect to the A-axis angle θ will be described with reference to FIG. First, the B-axis deviation angle α is measured at positions where the A-axis angle θ is 30, 60, and 90 degrees (deviation angle setting means). The B-axis deviation angle α is adjusted to 0 in advance at a position where the A-axis angle θ is 0 degrees (reference state). A method for measuring the B-axis deviation angle α will be described later. Then, the relationship between the A axis angle θ and the B axis deviation angle α is determined by interpolating (for example, linear approximation interpolation) between the measured angles (for example, between 0 degrees and 30 degrees) (relational expression setting means). . Based on this relationship, the B-axis deviation angle α is sequentially calculated (relational expression deviation angle calculation means).
[0034]
The B axis deviation angle α is measured using an edge locator (reference surface) 5 attached to the pallet 4 as shown in FIG. Specifically, first, as shown in FIG. 5A, the B-axis deviation angle α is adjusted to 0 at the position (reference state) where the A-axis angle θ is 0 degrees as described above. In this adjustment, the main shaft (not shown) to which a micrometer or the like is attached is moved in the X-axis direction in contact with the edge locator (reference surface) 5 and the B-axis is rotated so that the reading value becomes zero. Let Subsequently, the spindle is moved in the same manner as described above with the A-axis angle θ rotated to 30 degrees. Then, the B axis deviation angle α is calculated based on the read value. The same calculation is performed for 60 degrees and 90 degrees. FIG. 5B is a diagram showing a state in which the A-axis angle θ is rotated to 90 degrees.
[0035]
(Second Embodiment)
FIG. 6 shows an outline of the configuration of the table control apparatus according to the present invention. As shown in FIG. 6, the table control device includes an NC program interpretation unit 11, a pulse generation unit 12, an A-axis angle detection unit 13, a B-axis deviation angle calculation unit 14, a command value subtraction unit 15, Axis (X axis, Y axis, Z axis, A axis, B axis) servo control units 16-20. Here, the A-axis servo control unit 19 corresponds to a tilt table control means. The B-axis servo control unit 20 corresponds to a rotary table control unit. The B-axis deviation angle calculation unit 14 corresponds to deviation angle calculation means. The command value subtraction unit 15 corresponds to a rotary table correction unit.
[0036]
First, the NC program interpretation unit 11 interprets the input NC program. The command value of the NC program other than the B axis is sent directly to the pulse generator 12. The generated pulse output is sent to servo control units 16 to 19 of axes other than the B axis (X axis, Y axis, Z axis, A axis) to operate each axis other than the B axis.
[0037]
On the other hand, the command value of the B-axis NC program is sent to the pulse generator 12 after being separately processed. That is, first, the A-axis angle θ is detected by the A-axis angle detector 13. A B-axis deviation angle α is calculated according to the detected A-axis angle θ. This calculation process will be described later. Then, the command value subtraction unit 15 subtracts the command value of the B-axis NC program and the B-axis deviation angle α. The subtracted command value obtained by the subtraction is sent to the pulse generator 12, and the output is sent to the B-axis servo controller 20, thereby operating the B-axis. For example, when the command value of the B-axis NC program is 30 degrees and the B-axis deviation angle α is 0.002 degrees, the command value sent to the pulse generator 12 is 29.998 degrees.
[0038]
Next, the calculation process of the B-axis deviation angle α will be described with reference to the flowchart of FIG. First, it is determined whether or not the B-axis correction function is turned on (step S21). When the B-axis correction function is turned on, the A-axis angle θ detected by the A-axis angle detector 13 (shown in FIG. 6) is read (step S22). Subsequently, the B-axis deviation angle α is calculated based on the relationship of the B-axis deviation angle α with respect to the A-axis angle θ (step S23). The description of the relationship of the B-axis deviation angle α with respect to the A-axis angle θ is omitted because it is the same as the relationship in the first embodiment. Then, the process returns to step S21 and is repeated until the B-axis correction function is turned off.
[0039]
(Third embodiment)
In addition, although the above-mentioned embodiment demonstrated as a table control apparatus, this invention is not limited to an apparatus. That is, as long as a similar function can be realized, a method for executing table control, a program for causing a computer to function, or a computer-readable recording medium on which the program is recorded may be used. May be.
[0040]
【The invention's effect】
According to the table control device and the like of the present invention, when performing simultaneous multi-axis control machining, it is possible to remove the influence of the tilt angle of the tilt table on the machining accuracy of the workpiece and improve the machining accuracy.
[Brief description of the drawings]
FIG. 1 is a layout view of a tilt table and a rotary table.
FIG. 2 is a diagram showing a configuration of a table control device according to the first embodiment of the present invention.
FIG. 3 is a flowchart showing correction processing for a B-axis deviation angle.
FIG. 4 is a diagram illustrating a relationship of a B-axis deviation angle with respect to an A-axis angle.
FIG. 5 is a diagram showing a rotation angle of the rotary table when the tilt table is rotated.
FIG. 6 is a diagram illustrating a configuration of a table control device according to a second embodiment of the present invention.
FIG. 7 is a flowchart showing a calculation process of a B-axis deviation angle.
FIG. 8 is a diagram showing an inclination angle for mounting the tilt table.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Support member 2 ... Tilt table 3 ... Rotary table 4 ... Pallet 5 ... Edge locator 8 ... Encoder 9 ... B axis deviation angle calculation part (deviation angle calculation means)
10 ... B-axis origin position shift section (rotary table correction means)
DESCRIPTION OF SYMBOLS 11 ... NC program interpretation means 12 ... Pulse generation part 13 ... A-axis angle detection part 14 ... B-axis deviation angle calculation part (deviation angle calculation means)
15 ・ ・ ・ Command value subtraction unit (rotation table correction means)

Claims (8)

A tilt table rotatably supported by a pair of support portions, a tilt table control means for controlling the tilt table to rotate relative to the support portion, and a rotation about the normal axis of the tilt table on the tilt table A table control device having a rotary table that is arranged on the tilt table and on which a workpiece is placed, and a rotary table control unit that controls the rotation of the rotary table with respect to the tilt table.
The rotary table control means includes
A deviation angle calculating means for calculating a deviation angle of the workpiece around the axis that can be generated by rotation of the tilt table by the tilt table control means in accordance with a rotation angle of the tilt table;
And rotating table correction means for correcting the deviation angle by rotation of the rotation table in accordance with the rotation angle of the tilt table when the tilt table is rotated by the tilt table control means. Table controller. The deviation angle calculation means includes
A deviation angle setting means for presetting the deviation angle generated when the rotation angle of the tilt table is a predetermined rotation angle;
Relational expression setting means for setting a relational expression obtained by interpolating between predetermined rotation angles based on the set deviation angle;
The table control device according to claim 1, further comprising a relational expression deviation angle calculation unit that calculates the deviation angle based on the relational expression. The rotary table correction means includes
The table control device according to claim 1, wherein the origin position of the rotary table is shifted by the deviation angle. The rotary table control means is control means for controlling the rotation of the rotary table according to a command value of the NC program,
3. The table control device according to claim 1, wherein the rotation table correction means uses a subtraction command value obtained by subtracting the deviation angle from the command value of the NC program as a command value of the NC program. The table control device according to any one of claims 1 to 4 , wherein the pair of support portions are shifted in the center in the horizontal direction. A tilt table rotatably supported by a pair of support portions, a tilt table control means for controlling the tilt table to rotate relative to the support portion, and a rotation about the normal axis of the tilt table on the tilt table In a table control method for a machine tool, comprising: a rotary table that is arranged on the tilt table and on which a workpiece is placed; and a rotary table control unit that controls the rotary table to rotate relative to the tilt table.
A deviation angle calculating step of calculating a deviation angle of the workpiece around the axis that can be generated by rotation of the tilt table by the tilt table control means according to a rotation angle of the tilt table;
When the tilt table is rotated by the tilt table control means, a rotation table correction step for correcting the deviation angle according to the rotation angle of the tilt table by the rotation table control means according to the rotation angle of the tilt table. A table control method for a machine tool. A tilt table rotatably supported by a pair of support portions, a tilt table control means for controlling the tilt table to rotate relative to the support portion, and a rotation about the normal axis of the tilt table on the tilt table A table that functions as a table control method for a machine tool, having a rotary table that is arranged on the tilt table and on which a workpiece is placed, and a rotary table control unit that controls the rotation of the rotary table with respect to the tilt table. In the control program,
A deviation angle calculating step of calculating a deviation angle of the workpiece around the axis that can be generated by rotation of the tilt table by the tilt table control means according to a rotation angle of the tilt table;
A rotation table correction step for correcting the displacement angle by rotation of the rotation table by the rotation table control means when the tilt table is rotated by the tilt table control means; A program for controlling a table, which is executed by a computer. A tilt table rotatably supported by a pair of support portions, a tilt table control means for controlling the tilt table to rotate relative to the support portion, and a rotation about the normal axis of the tilt table on the tilt table A table that functions as a table control method for a machine tool, having a rotary table that is arranged on the tilt table and on which a workpiece is placed, and a rotary table control unit that controls the rotation of the rotary table with respect to the tilt table. In a computer-readable recording medium on which a control program is recorded,
A deviation angle calculating step of calculating a deviation angle of the workpiece around the axis that can be generated by rotation of the tilt table by the tilt table control means according to a rotation angle of the tilt table;
A rotation table correction step for correcting the displacement angle by rotation of the rotation table by the rotation table control means when the tilt table is rotated by the tilt table control means; A computer-readable recording medium on which a table control program recorded on a computer is recorded.

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