JP2007219951A - Attitude control method and nc machine tool for work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an attitude control method and an NC machine tool of work which enables simple and highly precise control of mounting attitude of work without being limited in shapes of a surface of work, quality of a material of work, etc. <P>SOLUTION: The method is for; measuring 3D coordinates on three arbitrary measuring points on a surface to be measured of a work 30 which is fixed to a table 11 using a measuring device 13; computing a tilting data and direction data of the surface to be measured of the work 30 by 3D coordinates of three measured measuring points; computing compensation data to the tilting data and the direction data for controlling the surface of the work to be measured into a predetermined posture; and controlling the surface of the work 30 to be measured into a predetermined posture by making the table 11 rotated with the computed compensation data. An NC machine tool 1 is used for this. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a workpiece attitude control method in machining a workpiece using an NC machine, and an NC machine tool suitably used for the method.

  Conventionally, workpieces (workpieces) are processed using complex machine tools with the same processing accuracy and precision using machine tools with predetermined processing performance and processing accuracy. I was going. In recent years, by using an NC machine tool, it is possible to automatically process a workpiece without requiring such a skilled technique.

  An NC machine tool is a machine tool that automatically processes a workpiece by numerically controlling the position and motion (speed, movement path, etc.) of the workpiece and tool, as shown in Patent Document 1, for example. It is mainly composed of a machine main body that processes a workpiece and an NC device that analyzes numerical data and controls the machine main body. Here, NC is an abbreviation for numerical control (Numerical Control).

In processing a workpiece using an NC machine tool or the like, it is necessary to accurately grasp and control the mounting posture of the workpiece attached to the table via a jig. However, the accuracy of the workpiece mounting posture may be deteriorated depending on the accuracy of mounting the jig on the table, the structure of the jig, the clamp deformation, the mechanical accuracy, and the like.
Therefore, conventionally, in order to maintain the accuracy of the mounting posture of the workpiece by the NC machine, a high-quality chuck with guaranteed repeatability is used as a jig to reduce the deterioration of the mounting accuracy, or a non-contact type After mounting, using a high-precision laser angle measuring instrument, contact-type measuring instrument, dial indicator, etc., the mounting posture was grasped, and necessary corrections were made as needed.

Of these, workpiece attachment posture control using a non-contact high-precision laser angle measuring instrument measures the angle of the workpiece surface by irradiating the workpiece surface with laser light and receiving the reflected light. Then, correction is performed based on the measured value.
In addition, the control of the mounting posture of the workpiece using the contact-type measuring instrument is to measure the X, Y, Z coordinates at two points on the surface of the workpiece and correct the angle of the plane with respect to the uniaxial direction. In other words, in the control of the mounting posture of the workpiece using the contact type measuring instrument, first, a surface parallel to the rotation direction of the table is measured at two points using an orthogonal axis perpendicular to the rotation axis, and the rotation direction is corrected. After that, in order to measure two points using an orthogonal axis perpendicular to the swing axis and to correct the swing direction, the measurement is performed at least twice on two planes.
Furthermore, the control of the mounting posture of the workpiece using the dial indicator is performed while moving the rotating shaft and the swing shaft based on the measured value of the dial indicator.

Japanese Patent Laid-Open No. 5-265519 (full text)

  However, in the conventional control of the mounting posture of the workpiece, the posture control of the table based on the measurement value by the measuring instrument is manually performed, and skill and labor required for this work are required.

  Moreover, the non-contact type high-precision laser angle measuring instrument is that the workpiece to be measured is limited to a material having a surface that reflects the irradiated laser beam, and the measuring instrument itself is expensive. When mounted on an NC machine, there are problems such as complicated handling due to the use environment and the mounting location.

  In addition, work correction using a contact-type measuring instrument requires repeated measurement (two planes) twice, so that work is time-consuming, and the surface that is nearly parallel to the rotation axis and swing axis is the work piece. However, the correction cannot be made unless there is at least one surface on the surface.

  The present invention has been made to solve the above-described problems, and is capable of easily and accurately controlling the mounting posture of a workpiece without being limited to the shape of the workpiece surface, the workpiece material, or the like. It is an object to propose a workpiece attitude control method and an NC machine tool that make it possible.

  In order to solve the above-described problems, the present invention provides a workpiece attitude control method using an NC machine, wherein the NC machine is input to a machine body including a table for fixing the workpiece and a movable main shaft. An NC device that analyzes the numerical data and controls the machine body, and the machine body is mounted on the surface to be measured of the work fixed to the table by a measuring instrument attached to the spindle. A step of measuring three-dimensional coordinates for each of three arbitrary measuring points, a step of importing the measured three-dimensional coordinates of the three measuring points into the NC device, and the NC device receiving 3 of the three measuring points A step of calculating inclination data and direction data of the surface to be measured of the workpiece by dimensional coordinates, and the inclination data for the NC device to control the surface to be measured of the workpiece to a predetermined posture; Calculating the correction data for the direction data, and the machine body controls the measured surface of the workpiece to the predetermined posture by rotating or moving the table according to the correction data calculated by the NC device. And a process.

  According to this workpiece posture control method, the NC device calculates the normal vector of the plane passing through the three measurement points based on the three-dimensional coordinates of the three arbitrary measurement points. Therefore, the posture of the surface of the workpiece is accurately calculated without requiring a reference surface that is almost parallel to the surface. Since the NC device corrects the tilt and direction of the table based on the calculated posture of the workpiece surface, the NC device can easily and accurately control the workpiece surface to a predetermined posture.

  Further, in the workpiece attitude control method, if each of the steps is repeated until an arbitrary indexing accuracy is ensured, the workpiece attitude can be controlled with high accuracy even if an error occurs during correction. It is possible. Since the measurement and control of the posture of the surface of the workpiece is automatically performed by the control of the NC device, it can be performed easily and in a short time.

  In the workpiece posture control method, if the measuring device is a contact-type measuring device, it is possible to control the posture of the workpiece with high accuracy via a relatively inexpensive device, which is preferable. .

  In the workpiece posture control method, if the NC machine is an NC machine tool that performs machining on the workpiece with a tool attached to the spindle, workpiece posture control and workpiece machining are performed continuously. It is possible and preferable.

  In the workpiece posture control method, if the surface to be measured is a surface to be processed that constitutes a flat surface, the angle of the surface to be processed is directly measured and corrected so that the surface to be measured against a tool (for example, a drill) is corrected. The processing surface angle can be easily set to a predetermined angle (for example, a right angle with respect to the tool) and does not require complicated calculation processing.

  Further, in the workpiece attitude control method, the NC machine tool is a 5-axis control device configured by orthogonal 3-axis and table-rotation type 2-axis rotary tables, and rotates the table-rotation-type 2-axis rotary table. By controlling the measured surface of the workpiece to the predetermined posture, it is preferable because it can be performed easily and with high accuracy even when an NC machine tool that is a 5-axis control device is used. .

  Further, the NC machine tool of the present invention includes a table for fixing a workpiece and a movable main shaft to which a tool or a measuring device can be attached, and is fixed to the table using the tool or measuring device attached to the main shaft. An NC machine tool comprising: a machine body that performs predetermined machining on a workpiece that has been processed; and an NC device that analyzes input numerical data and controls the machine body, wherein the NC device performs machining. Machining posture storage means for storing the posture of the surface of the workpiece to be processed with respect to the spindle, and measurement coordinate storage means for storing three-dimensional coordinates of arbitrary three points on the surface of the workpiece measured by the measuring device Calculated based on the three-dimensional coordinates of the three points stored in the measurement coordinate storage means, and an attachment posture calculation means for calculating the current posture of the surface of the workpiece, and the attachment posture calculation means. Based on the correction value calculated by the correction value calculating means and the correction value calculating means for calculating a correction value for matching the current attitude with the machining attitude stored in the machining attitude storage means. And a posture control instruction transmitting means for transmitting an instruction to rotate or move the table to the main body.

  According to the NC machine tool, since the posture of the workpiece to be machined can be automatically controlled to a desired posture via the NC device, the workpiece can be machined easily and with high accuracy. It becomes.

  According to the workpiece posture control method and NC machine tool according to the present invention, it is possible to easily and accurately control the workpiece mounting posture in machining of a workpiece using the NC machine tool, and hence high quality. It is possible to easily process a workpiece. In addition, according to the workpiece posture control method of the present invention, it is possible to process a workpiece with high accuracy without being limited to the shape of the workpiece surface, the workpiece material, or the like.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.
Here, FIG. 1 is a perspective view showing a main part of the NC machine tool according to the present embodiment. FIG. 2 is a block diagram showing the configuration of the NC device of the NC machine tool shown in FIG. FIG. 3 is a flowchart illustrating the procedure of the workpiece posture control method according to the present embodiment. 4 (a) to 4 (d) are perspective views showing respective situations of the workpiece posture control method according to the present embodiment. 5A to 5C are schematic views showing a calculation method of the workpiece posture control method according to the present embodiment.

  As shown in FIG. 1, the NC machine tool 1 according to the present embodiment mainly includes a machine main body 10 and an NC device 20. In the present embodiment, a 5-axis control machining center is used as the NC machine tool 1. Here, in this embodiment, a vertical type is used as the machining center, but the type of the machining center is not limited, and may be a horizontal type, for example. Furthermore, not only a machining center, but also a multi-tasking machine having a 1-axis rotary table and a swinging tilt head, a 5-axis control inspection device with a 2-axis rotary table mounted on a three-dimensional measuring instrument, etc. The present invention is applicable to any NC machine having three axes orthogonal to each other.

The machine body 10 can fix a work 30 and can be mounted with a table 11 capable of rotating in the A-axis and C-axis directions and a tool or measuring instrument 13, and can move in the X-axis, Y-axis, and Z-axis directions. The main shaft 12 is provided. Then, a tool is attached to the spindle 12 and a predetermined process is performed on the workpiece 30 fixed to the table 11, or a measuring surface of the workpiece 30 fixed to the table 11 is attached to the spindle 12 by measuring the measuring device 13. I do.
The tool or measuring instrument 13 attached to the spindle 12 is provided in a tool magazine (not shown), and is automatically attached to and detached from the spindle 12 via an arm (not shown) according to an instruction from the NC device 20.

  As shown in FIG. 1, the table 11 is a two-axis rotary table type, and is composed of a circular rotary table 11a that rotates in the C-axis direction and a tilt table 11b that rotates in the A-axis direction. . And the table 11 rotates the tilt table 11b with the power of the 1st table motor 11c according to the instruction | indication of NC apparatus 20, and the 2nd table motor (not shown) arrange | positioned directly under the table 11 is used. The direction (posture) of the work 30 is changed by rotating the rotary table 11a with power.

  The main shaft 12 is configured by an orthogonal three-axis system that moves a tool or measuring instrument 13 mounted on the main shaft 12 in the vertical, horizontal, and longitudinal directions (Z-axis, X-axis, and Y-axis directions). The spindle 12 performs processing or measurement on the surface (surface to be measured) of the workpiece 30 and moves in accordance with an instruction from the NC device 20. Needless to say, the configuration of the movement method of the spindle 12 is not limited, and may be, for example, a portal type.

  In the present embodiment, a touch probe that is a contact-type measuring instrument is used as the measuring instrument 13 that measures the posture of the surface of the workpiece 30. Needless to say, the type of the measuring device 13 is not limited. For example, a non-contact type measuring device such as a laser length measuring device may be used.

  The NC device 20 is a device that analyzes input numerical data and controls the machine body 10. As shown in FIG. 2, the NC device 20 stores various data and a storage unit 21 that stores various data. A calculation unit 22 that calculates various numerical values based on the data; an instruction unit 23 that issues a control command to the machine body 10 based on the data in the storage unit 21 and the calculation result of the calculation unit 22; an input device 24; It has.

  As shown in FIG. 2, the storage unit 21 includes a machining posture storage unit 21 a that stores a posture of the workpiece 13 to be measured with respect to the spindle 12 during machining, and a workpiece 30 measured by the measuring instrument 13 on the surface to be measured. Measurement coordinate storage means 21b for storing the three-dimensional coordinates of any three points, correction value storage means 21c for storing the correction value of the posture of the workpiece calculated by the calculation unit 22, and machining of the workpiece 30 inputted in advance Machining program storage means 21d for storing the program.

  As shown in FIG. 2, the calculation unit 22 includes an attachment posture calculation unit 22 a that calculates the current posture of the surface to be measured of the workpiece 30 based on the three-dimensional three-dimensional coordinates stored in the measurement coordinate storage unit 21 b. A machining posture calculation unit 22b that calculates a posture during machining of the workpiece 30 according to the machining program stored in the machining program storage unit 21d, and a machining posture storage unit that calculates the current posture of the workpiece 30 calculated by the attachment posture calculation unit 22a. The correction value calculation means 22c for calculating a correction value for matching with the posture of the workpiece 30 at the time of machining stored in 21a, and the axis of the table 11 when performing automatic repeated measurement until an arbitrary indexing accuracy is ensured Measurement coordinate conversion calculating means 22d for converting the three measurement points measured again after correcting to the coordinates before the table axis correction. Here, the table axis before the table axis correction is A = 0 ° and C = 0 °.

  As shown in FIG. 2, the instruction unit 23 includes a measurement instruction unit 23 a that gives an instruction to the machine body 10 and correction values calculated by the correction value calculation unit 22 c in order to obtain posture data of the measurement target surface of the workpiece 30. Based on the value, the attitude control instruction means 23b for transmitting an instruction to rotate the table 11 to the machine body 10 and the machining program for transmitting the machining instruction for the workpiece 30 to the machine body 10 based on the machining program stored in the storage unit 21. Instruction means 23c.

  The input device 24 includes a mouse, a keyboard, an NC tape reading unit, a storage medium reading unit, and the like (not shown), and is a device that inputs and operates various data necessary for the operation of the NC device 20.

Next, a workpiece attitude control method according to the present embodiment will be described.
As shown in FIG. 3, the posture control of the workpiece includes (1) a preparation step S1, (2) a coordinate measurement step S2, (3) a measurement value capturing step S3, and (4) an attachment posture calculation step S4. (5) It is comprised from correction value calculation process S5, and (6) attitude | position control process S6.

(1) Preparation step S1
In the preparation step S1, as shown in FIG. 4A, after the measuring instrument 13 is installed on the spindle 12 (see FIG. 1), the worker manually places the measuring instrument 13 on the table 11 and works 30. About 10 mm above the surface to be measured. Here, in this embodiment, the surface to be measured of the workpiece 30 is set as a surface to be processed (hereinafter, simply referred to as “processed surface”) 31 constituting a plane (see FIG. 4B).
In the preparation step S1, a machining program for the workpiece is input to the NC device 20 in advance and stored in the machining program storage means 21d. In this embodiment, the machining program is input by reading an NC tape (not shown) in which machining program data is entered by the NC tape reading means of the input device 24. Note that the input method of the machining program is not limited, and may be appropriately selected from known methods.

  Here, when the machining program is input to the NC device 20, the machining program is stored in the machining program storage unit 21d, and the machining posture calculation unit 22b of the calculation unit 22 is activated, and the workpiece 30 according to the machining program is activated. The machining posture is calculated. The calculated machining posture of the workpiece 30 is stored in the machining posture storage means 21 a of the storage unit 21.

(2) Coordinate measurement process S2
In the coordinate measuring step S2, the operator operates the input device 24 to activate the measurement instructing means 23a of the NC device 20, so that the processing surface (measured surface) 31 of the workpiece 30 by the measuring device 13 is measured. It is a process of performing. The workpiece 30 (machined surface 31) is measured as shown in FIG. 4B by measuring the X, Y, and Z coordinates of any three points (P1, P2, P3) on the machined surface 31. . Here, the larger the area formed by the measurement points P1, P2, and P3, the more accurately the posture of the processed surface 31 of the workpiece 30 can be measured. Therefore, when the area of the machining surface 31 constituting the plane is small, a flat plate having a larger area than the machining surface 31 is placed on the machining surface 31 so as to be parallel to the machining surface 31, thereby measuring range. May be spread.

(3) Measurement value capturing step S3
The measurement value capturing step S3 is a step of storing the measurement result of the processed surface 31 of the workpiece 30 measured in the coordinate measurement step S2 in the measurement coordinate storage unit 21b.
When the measurement of the machining surface 31 of the workpiece 30 by the measurement instruction unit 23a is completed, the measurement coordinate storage unit 21b of the storage unit 21 is activated, and the measurement points P1, P2, P3 on the machining surface 31 measured by the measuring device 13 are activated. The coordinate data is stored.

(4) Mounting orientation calculation step S4
In the attachment posture calculation step S4, the current attachment posture of the workpiece 30 is calculated based on the coordinate data of the measurement points P1, P2, and P3 of the machining surface 31 stored in the measurement coordinate storage unit 21b in the measurement value capturing step S3. It is a process.
When the acquisition of the coordinate data of the measurement points P1, P2, P3 on the machining surface 31 is completed in the measurement value acquisition step S3, the attachment posture calculation means 22a of the calculation unit 22 is activated to calculate the attachment posture of the workpiece 30. Is called.

  As shown in FIG. 5A, calculation of the mounting posture of the workpiece 30 is performed using the X, Y, Z coordinates of three points (P1, P2, P3) on the machining surface 31 of the workpiece 30. This is done by calculating 31 normal vectors N1.

  The normal vector N1 is calculated by calculating the constants A, B, C, and D by applying the plane equation (Equation 1) to the coordinate data of the three points (P1, P2, P3) shown in Table 1. This is done by substituting constants A, B, and C into the formula (formula 2) of the normal vector N1.

AX + BY + CZ + D = 0 (Formula 1)
N1 = (A, B, C) (Expression 2)

(5) Correction value calculation step S5
The correction value calculation step S5 is a step of calculating a correction value for matching the posture data of the workpiece 30 calculated in the mounting posture calculation step S4 with the machining posture of the workpiece 30 stored in the machining posture storage means 21a. is there.

  When the calculation of the attachment posture of the workpiece 30 by the attachment posture calculation means 22a is completed, the correction value calculation means 22c of the calculation unit 22 is activated, and the machining posture of the workpiece 30 stored in the machining posture storage means 21a of the storage unit 21 is obtained. Calculation of a correction value for matching the mounting posture is started. In the present embodiment, the machining posture of the workpiece 30 is the direction in which the machining surface 31 is perpendicular to the tool (Z axis) installed on the spindle 12, that is, the direction in which the normal vector N1 coincides with the Z axis. And

  The correction value is calculated by calculating the C-axis correction amount θ (see FIG. 5B) formed by the angle formed by the XY plane projection normal vector N11 obtained by projecting the normal vector N1 onto the XY plane and the Y axis, and the normal vector. This is done by calculating an A-axis correction amount φ (see FIG. 5C) that is an angle formed by the YZ plane projection normal vector N12 obtained by projecting N1 onto the YZ plane and the Z axis.

  As shown in FIG. 5B, the C-axis correction amount θ is calculated by the following procedure.

A general expression of the normal vector N1 passing through the origin is expressed by Expression 3.
X / A = Y / B = Z / C (Formula 3)
When the normal vector is projected onto the XY plane according to Equation 3, Equation 4 is obtained.
X = (A / B) × Y (Formula 4)
Accordingly, the C-axis correction amount θ is as follows.
θ = ARCTA (A / B) (Formula 5)

  As shown in FIG. 5C, the A-axis correction amount φ is calculated by the following procedure.

If an arbitrary vector on the XY plane is N2 = (0, 0, 1), an angle φ ′ formed by the normal vector N1 and the XY plane is expressed by Equation 6.
φ ′ = ARCCOS (N1 · N2 / | N1 || N2 |) (Formula 6)
When the normal vector N1 is rotationally projected onto the YZ plane, the angle φ ′ formed between the normal vector N1 and the XY plane is equal to the angle φ ″ formed between the YZ plane rotational projection vector and the Y axis. The quantity φ is calculated from Equation 7.
φ = 90 ° −φ ″ = 90 ° −φ ′ (Expression 7)

(6) Posture control step S6
The posture control step S6 is a step of correcting the posture of the workpiece 30 based on the correction values (C-axis correction amount θ and A-axis correction amount φ) calculated in the correction value calculation step S5.

  When the correction value (C-axis correction amount θ, A-axis correction amount φ) is calculated by the correction value calculation unit 22c, the correction value is temporarily stored in the correction value storage unit 21c. Then, the correction value is stored in the correction value storage unit 21c, the posture control instruction unit 23b of the instruction unit 23 is activated, and the posture control instruction of the workpiece 30 is transmitted to the machine body 10.

When the attitude control instruction unit 23b is activated, an instruction to rotate the rotary table 11a based on the C-axis correction amount θ (see FIG. 5B) stored in the correction value storage unit 21c is transmitted to the machine body 10. In response to this instruction, the second table motor of the machine body 10 is driven to rotate the rotary table 11a by the C-axis correction amount θ as shown in FIG.
When the correction of the workpiece 30 with respect to the C-axis is completed, a rotation instruction for the tilt table 11b based on the A-axis correction amount φ (see FIG. 5C) stored in the correction value storage means 21c is sent to the machine by the attitude control instruction means 23b. It is transmitted to the main body 10. By this instruction, the first table motor 11c of the machine body 10 is driven to rotate the tilt table 11b by the A-axis correction amount φ as shown in FIG.

When the posture control of the workpiece 30 is completed by the respective steps (S1 to S6), the machining instruction unit 23c is activated, and a machine 30 is instructed to machine the workpiece 30 according to the machining program stored in the machining program storage unit 21d. Transmission to the main body 10 starts machining the workpiece 30.
In the present embodiment, the parallelism of the processed surface 31 of the workpiece 30 is set to be within 0.001 ° by repeating the steps of the coordinate measurement step S2 to the posture control step S6 a plurality of times. Here, it goes without saying that the target value of the parallelism of the processed surface is not limited to within 0.001 °, and may be set as appropriate. Further, the number of times of repeating the coordinate measurement step S2 to the posture control step S6 is not limited, and it is needless to say that it is not necessary to repeat the correction as long as high-precision correction is possible only once.

  Further, when the steps of the coordinate measurement step S2 to the posture control step S6 are repeated, if the position of the table 11 is moved by the previous posture control (immediately before it is repeated), the measurement coordinate conversion calculation unit of the calculation unit 22 is moved. 22d is activated, and the repeated operation of each process (coordinate measurement process S2 to attitude control process S6) is started with the corrected coordinates (X ″, Y ″, Z ″) calculated by the following procedure as the origin. Thus, it goes without saying that the measurement coordinate conversion calculation means 22d may be started manually.

  When the measurement coordinate conversion calculation unit 22d is activated, first, arbitrary three points on the machining surface 31 of the workpiece 30 are set to arbitrary X, Y, Z coordinates, that is, positions (coordinates) of the A axis and C axis of the table 11 are arbitrary. The measurement coordinates X, Y, Z in the case are acquired.

  Next, the measurement coordinates X, Y, and Z are converted into coordinates X ′, Y ′, and Z ′ when the coordinate of the A axis is 0 and the coordinate of the C axis is arbitrary according to Equation 8.

  Next, the coordinates X ′, Y ′, Z ′ when the coordinates of the A axis are 0 and the coordinates of the C axis are arbitrary, and the corrected coordinates when the coordinates of the A axis and the C axis are both 0 according to Equation 9. Convert to X ″, Y ″, Z ″.

  Then, using the corrected coordinates X ″, Y ″, Z ″ when the coordinates of the A axis and the C axis are both 0 as the origin, the posture control of the work surface 31 of the workpiece 30 by the coordinate measurement step S2 to the posture control step S6 is performed. Do.

  As described above, according to the embodiment, the NC apparatus 20 automatically corrects the posture of the workpiece 30 based on the measurement result of the measurement target surface (machined surface 31) of the workpiece 30, so that a special technique or the like is required. Therefore, the posture of the workpiece 30 can be corrected easily and with high accuracy. In other words, after the work 30 is set on the table 11, the posture of the work 30 is automatically corrected only by starting the NC device 20, so that it is easy to perform without requiring the skill of an operator. Therefore, it is preferable.

  Further, even when processing the surface 31 that is an inclined surface straight, it is possible to accurately determine the inclined surface horizontally and to process the surface straight.

  By repeating the coordinate measurement step S2 to the posture control step S6 a plurality of times, for example, because the angle of the machining surface 31 of the workpiece 30 is steep, the surface of the machining surface 13 of the measuring device 13 is measured at the time of measurement by the measuring device 13. Even when the measurement value is unstable due to the sliding of the measuring element, the correction is made gradually and high-precision posture control is possible.

As mentioned above, although preferred embodiment was described about this invention, this invention is not limited to the said embodiment, A design change is possible suitably in the range which does not deviate from the meaning of this invention.
For example, in the above-described embodiment, the 5-axis control device is used as the NC machine tool. However, the type of the NC machine tool used in the workpiece attitude control method of the present invention is not limited and is appropriately known. It can be used by selecting from the NC machine tools. In the above-described embodiment, the machining center is used. However, the present invention can be applied to a transfer machine, a multi-task machine, and an inspection apparatus as long as the machine is a 5-axis control machine.

  In the embodiment, the workpiece surface to be measured is measured as the workpiece measurement surface during workpiece posture control. However, if the relative relationship with the workpiece surface is clear, the workpiece surface is not necessarily measured. For example, a plane adjacent to the surface to be processed may be measured as the surface to be measured.

Further, the surface to be measured in the workpiece posture control method of the present invention does not necessarily have to be a plane if the three measurement points are on the same plane. As an example where the surface to be measured is not flat,
For example, when a workpiece having a plurality of parallel surfaces with steps is measured after a step amount is previously input as a correction amount into a variable, or when three measurement points are acquired as center coordinates of three reference spheres, etc. There is.

  In the above embodiment, the normal vector of a plane passing through three points is used for the calculation method for obtaining the mounting posture. However, the calculation method by the mounting posture calculation means is not limited to the method of the above embodiment. Not too long. For example, it is possible to correct the mounting posture by using a direction vector from the central axis coordinate of a three-dimensional circle passing through three measuring points to the highest point of the Z coordinate on the arc of the three-dimensional circle. .

  The workpiece control method of the present invention and the workpiece to be machined by the NC machine tool are not limited, and can be applied to any precision machining. For example, it can be suitably used for a work that requires high-precision processing, such as a metal frame of an implant.

  Further, when the work surface of the workpiece changes at any time according to the machining program, the workpiece posture may be corrected by the workpiece posture control method of the present invention each time the workpiece orientation changes. .

It is a perspective view which shows the principal part of the NC machine tool which concerns on this embodiment. It is a block diagram which shows the structure of NC apparatus of the NC machine tool which concerns on this embodiment. It is a flowchart which shows the procedure of the attitude | position control method of the workpiece | work which concerns on this embodiment. (A)-(d) is a perspective view which shows each condition of the attitude | position control method of the workpiece | work which concerns on this embodiment. (A)-(c) is the schematic which shows the calculation method of the attitude | position control method of the workpiece | work which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 NC machine tool 10 Machine main body 11 Table 12 Spindle 13 Measuring device 20 NC apparatus 21 Memory | storage part 21a Machining attitude | position storage means 21b Measurement coordinate memory | storage means 22 Calculation part 22a Mounting attitude | position calculation means 22c Correction value calculation means
23 Instructing unit 23b Posture control instructing means 30 Work S1 Preparation step S2 Coordinate measurement step S3 Measurement value capturing step S4 Mounting posture calculation step S5 Correction value calculation step S6 Posture control step

Claims (7)

A workpiece attitude control method using an NC machine,
The NC machine includes a machine body including a table for fixing a workpiece and a movable spindle, and an NC device that analyzes input numerical data and controls the machine body,
A step of measuring three-dimensional coordinates for each of three arbitrary measuring points on a surface to be measured of a workpiece fixed to the table by a measuring instrument attached to the spindle, the machine body;
Importing the measured three-dimensional coordinates of the three measuring points into the NC device;
The NC device calculates tilt data and direction data of the surface to be measured of the workpiece based on the three-dimensional coordinates of the three measurement points taken in;
The NC device calculating correction data for the tilt data and direction data for controlling the surface to be measured of the workpiece to a predetermined posture;
The machine body controls the measured surface of the workpiece to the predetermined posture by rotating or moving the table according to the correction data calculated by the NC device;
A workpiece attitude control method comprising:   The work posture control method according to claim 1, wherein the steps are repeatedly performed until an arbitrary indexing accuracy is ensured.   3. The workpiece posture control method according to claim 1, wherein the measuring device is a contact-type measuring device.   The workpiece NC attitude control method according to any one of claims 1 to 3, wherein the NC machine is an NC machine tool that performs machining on the workpiece with a tool attached to the spindle. .   The work posture control method according to claim 4, wherein the surface to be measured is a surface to be processed that forms a flat surface. The NC machine tool is a 5-axis control device configured with orthogonal 3-axis and table-rotation type 2-axis rotary tables,
6. The work posture control method according to claim 4, wherein the surface to be measured of the work is controlled to the predetermined posture by rotating the table rotation type biaxial rotary table. A machine comprising a table for fixing a workpiece and a movable main shaft to which a tool or a measuring device can be attached, and performing a predetermined process on the workpiece fixed to the table using the tool or measuring device attached to the main shaft The body,
An NC machine tool including an NC device that analyzes input numerical data and controls the machine body,
The NC device stores a working posture storage means for storing a working posture of the workpiece surface to be measured with respect to the spindle,
Measuring coordinate storage means for storing three-dimensional coordinates of arbitrary three points on the surface to be measured of the workpiece measured by the measuring device;
An attachment posture calculation means for calculating the current posture of the surface to be measured of the workpiece based on the three-dimensional coordinates of the three points stored in the measurement coordinate storage means;
Correction value calculating means for calculating a correction value for making the current posture calculated by the attachment posture calculating means coincide with the posture at the time of machining stored in the machining posture storage means;
Attitude control instruction transmission means for transmitting an instruction to rotate or move the table to the machine body based on the correction value calculated by the correction value calculation means;
An NC machine tool characterized by comprising:

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