JP2011255463A - Numerical control device of wire-cut electric discharge machine equipped with rotating shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a numerical control device of a wire-cut electric discharge machine equipped with a rotating shaft which can stabilize working in the case of a nonconstant radius of rotation.SOLUTION: In steps SA100-SA104, the presence or absence of a command block clearly specifying an initial radius of rotation is determined; an initial radius R of rotation is read into substitute a present radius Ra of rotation with the initial radius R of rotation in the case of the presence of the command block; and the amount X of the movement of a linear shaft and the amount A of movement of the rotating shaft are acquired in the case of the absence of the command block. In steps SA105-SA110, the presence or absence of the command of the radius of rotation is determined by substituting the present radius Ra of rotation into a radius Rs of rotation at a starting point; the radius R of rotation is substituted into a radius Re of rotation at an end point in the case of the presence of the command of the radius of rotation; the present radius Ra of rotation is substituted into the radius Re of rotation at the end point in the case of the absence of the command of the radius of rotation; a value obtained by subtracting the radius Rs of rotation at the starting point from the radius Re of rotation at the end point is substituted into an increment Rinc of the radius of rotation; and an integrated value SUMa of the amount of movement is set at 0 as an initial value.

Description

  The present invention relates to a numerical control device for a wire cut electric discharge machine, and more particularly to a numerical control device for a wire cut electric discharge machine having a rotating shaft.

  In Patent Document 1 and Patent Document 2, when a spiral groove is machined in a high-hardness collet chuck component used for fixing a tool such as a drill, the workpiece is rotated and the wire electrode is moved at the same time. A wire-cut electric discharge machine that performs desired machining is disclosed. The collet chuck is a gripping tool that does not easily damage the material because the material is gripped by the entire cylindrical inner surface.

  FIG. 6 is a diagram for explaining that desired processing is performed by rotating the workpiece 1 and simultaneously moving the wire electrode 2 using a wire cut electric discharge machine. As shown in FIG. 6, the workpiece is rotated and simultaneously the wire electrode is moved to perform desired processing. A numerical control device that controls a wire-cut electric discharge machine issues a movement command simultaneously to a rotation axis for rotating a workpiece and a linear axis for moving a wire electrode.

At this time, the numerical control device issues a movement command simultaneously to the rotation axis for rotating the workpiece and the linear axis for moving the wire electrode. Conventionally, the following (a) or The control (b) is performed.
(A) The linear axis (wire electrode) moves at the command speed, and the rotation axis (workpiece rotation) follows the movement of the wire electrode.
(B) The rotation axis movement command unit [deg] and the linear axis movement command unit [mm] are regarded as the same, and control is performed so that the combined speed of the linear axis and the rotation axis becomes the command speed.

Japanese Utility Model Publication No. 2-97524 Japanese Patent Laid-Open No. 7-136853

  In both methods (a) and (b), the speeds of the linear axis and the rotary axis are constant, but as the work 1 progresses, the position where the work 1 is processed (work processing point) and the center of rotation. And the distance (rotation radius) changes. The turning radius at the position where the workpiece 1 is machined may change for each block of the machining program or may gradually change from the start point to the end point of one block.

  FIG. 7 is a diagram for explaining that the distance from the center of rotation at the workpiece machining point to the workpiece machining point changes as machining of the workpiece 1 proceeds. In FIG. 7, when the workpiece machining progresses, the distance (rotation radius) from the rotation center to the workpiece machining point at the workpiece machining point changes from r1 to r2. Since the relative speeds of the wire electrode 2 and the workpiece 1 change due to the different radii of rotation at the workpiece machining points 7a, 7b, 8a, 8b by the wire electrode 2, the discharge state changes and the machining is not stable. There was a point.

  As a countermeasure against this, there is a conventional method in which a machining program is divided into blocks with a minute movement amount, and a command speed is calculated and commanded so that the relative speeds of the wire electrode and the workpiece are equal for each block. However, it takes time to calculate the commanded speed and to create a machining program, and there is a problem that the machining program increases.

  Therefore, in view of the problems of the prior art described above, the object of the present invention is to perform machining by rotating a workpiece with a wire-cut electric discharge machine, in particular, it is possible to stabilize machining when the rotation radius is not constant, It is to provide a numerical control device of a wire cut electric discharge machine having a rotating shaft.

The invention according to claim 1 of the present application is capable of relatively moving a workpiece in an axial direction perpendicular to each other with respect to a wire electrode stretched by an upper wire electrode guide and a lower wire electrode guide, and In a numerical controller of a wire cut electric discharge machine that controls a wire cut electric discharge machine that can be rotated according to a machining program, storage means for storing a rotation radius at a workpiece machining point at an end point of each block of the machining program; A reading means for reading from the storage means the turning radius at the end point in the block to be executed and the workpiece machining point at the end point in the previous block, the turning radius of the end point of the previous block read from the storage means, and the rotation of the end point of the block to be executed From the radius and the amount of movement of the rotary shaft Calculation means for calculating a turning radius at a point; and control means for controlling the relative speed between the wire electrode and the workpiece machining point from the turning radius calculated by the calculating means so as to become a command speed. Is a numerical control device of a wire cut electric discharge machine.
The invention according to claim 2 is characterized in that the turning radius stored in the storage means is a value obtained by instructing each block in a machining program and analyzing the machining program. It is a numerical control apparatus of the wire cut electric discharge machine of Claim 1.

  According to the present invention, in machining performed by rotating a workpiece with a wire-cut electric discharge machine, numerical control of a wire-cut electric discharge machine equipped with a rotating shaft is possible, particularly when the rotation radius is not constant. Equipment can be provided.

It is a figure explaining the structure of the numerical control apparatus of a wire cut electric discharge machine. This is an example in which the turning radius at the block end point is commanded by a machining program. FIG. 3 is a diagram illustrating machining of a workpiece by the machining program of FIG. 2. It is a figure explaining that the rotation radius in an upper workpiece | work processing point and the rotation radius in a lower workpiece | work processing point may differ depending on the inclination direction of a wire electrode. It is a flowchart explaining the algorithm of the process concerning this invention. It is a flowchart explaining the algorithm of the process concerning this invention. It is a figure explaining using a wire electric discharge machine and rotating a workpiece | work and moving a wire electrode simultaneously, and performing a desired process. It is a figure explaining that the distance from the rotation center in a workpiece machining point to a workpiece machining point changes as machining progresses.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is demonstrated about the same or similar structure as a prior art.
FIG. 1 is a diagram illustrating a configuration of a numerical control device of a wire cut electric discharge machine. The table 12 is guided by a guide structure (not shown) and can move in two axial directions within a horizontal plane. The table 12 is moved in the respective directions by the X-axis motor 14 and the Y-axis motor 16. A machining tank (not shown) is fixed on the table 12, and the machining liquid 30 is filled in the machining tank.
A rotary drive device 20 that forms the A axis is fixed to the column portion 18 of the table 12, and the rotary shaft 21 is driven to rotate by an A axis motor 22. The A axis motor 22 includes an A axis speed detector 23 and an A axis. An angle detector 24 is attached. A workpiece fixing bracket 25 that holds the workpiece 1 is attached to the tip of the rotating shaft 21.

  The wire electrode 2 facing the workpiece 1 held by the workpiece fixing bracket 25 via a machining gap is given a predetermined tension by a roller and a tension roller (not shown) and is stretched vertically. The wire electrode 2 is stretched vertically by being given a predetermined tension by a drive roller and a tension roller (not shown). The wire electrode 2 is guided by a die-shaped upper wire guide 9 and a lower wire guide 10 which are arranged vertically. The position in the horizontal plane is determined. An electric supply (not shown) is brought into sliding contact with the wire electrode 2, and a pulsed voltage is applied from a power supply (not shown). Processing is performed by generating electric discharge between the wire electrode 2 and the workpiece 1 by the pulse voltage.

  The X-axis and Y-axis motors 14 and 16 that move the table 12 in a horizontal plane and the A-axis motor 22 that rotates the workpiece 1 are connected to a numerical control device 40 and are driven and controlled. The A-axis speed detector 23 and the A-axis angle detector 24 are also connected to the numerical controller 40 for A-axis control. The numerical control device 40 includes a CPU 41 that is a processor for analyzing a machining program and controlling the entire wire cut electric discharge machine, a memory 42 for storing various data and machining programs, control circuits 43, 44, and 45 for each axis, Shaft amplifiers 46, 47 and 48 are provided. These structures are conventionally known.

  The X-axis and Y-axis motors 14 and 16 that drive the table 12, these axis control circuits 43 and 44, amplifiers 46 and 47 in the numerical controller 40, etc., attach the work 1 to the stretched wire electrode 2. A plane moving means for relatively moving in one plane is configured. The various detectors 23 and 24 for controlling the A-axis motor 22, the A-axis axis control circuit 45, and the A-axis amplifier 48 constitute a rotation control device. The machining power supply 50 is a device that applies a machining pulse voltage between the workpiece 1 and the wire electrode 2. Note that a circuit between the work power source 50 and the workpiece 1 and the wire electrode 2 is not shown. The CPU 41 can acquire the command speed Fc from the machining power supply 50.

  The workpiece 1 is gripped by the workpiece fixing bracket 25 of the rotary shaft 21 and processed while being immersed in the processing liquid 10 in a processing tank (not shown). The workpiece 1 can be machined by performing electrical discharge machining while simultaneously controlling the rotary shaft 21 (A axis) with the X axis and the Y axis. The workpiece 1 can be processed by simultaneously controlling the rotary shaft 21 (A axis) and the X-axis motor 14, or the rotary shaft 21 (A axis) and the Y-axis motor 16 can be controlled simultaneously. Thus, the workpiece 1 can be processed.

Next, control for stabilizing the machining according to the present invention will be described.
In order to stabilize the machining of the workpiece 1 by the wire electrode 2, the relative speed between the wire electrode 2 and the workpiece 1 at the workpiece machining point may be controlled to be the command speed Fc (see FIG. 7). If the turning radius r at the workpiece machining point is known, the speed of the linear axis and the speed of the rotating shaft are obtained so as to satisfy Equation (1).

Command speed Fc = √ (Fx ² + Fa ² ) (Expression 1)
Where Fx = linear axis speed (mm / min)
Fa = speed of rotation axis (deg / min) * π * r (mm) / 180 (deg)
Since the turning radius at the workpiece machining point, that is, which position of the workpiece is to be machined is clear when the machining program is created, it is only necessary to know the turning radius of each block intended when creating the machining program.

  In the present invention, the rotation radius at the block end point is designated for each block. If the turning radius at the end point of the block changes from the value in the previous block, it means that the turning radius gradually changes from the start point to the end point of the block. By controlling the relative speed between the wire electrode and the workpiece at the processing point to be the command speed from the given turning radius, the processing is stabilized.

  FIG. 2 shows an example in which the turning radius at the block end point is commanded by the machining program. R is the radius of rotation at the end of the block. G999 is a command that specifies the initial turning radius.

G00X0Y0. Means positioning to the machining start position of X0Y0.
G999R30. Is the initial turning radius = 30.
G01X10. A10. R30. Is assumed that the radius of rotation at the position of X10A10 = 30.
G01X20. A0. R35. Is the radius of rotation at the position X20A0 = 35. As a result, the turning radius changes from 30 to 35.
G01X30. A10. R35 is set so that the radius of rotation at the position of X30A10 = 35.

  FIG. 3 illustrates machining of a workpiece by the machining program of FIG. X0, X10, X20, and X30 in the figure are commands in each block of FIG. The wire electrode 2 moves relative to the wire electrode moving direction (linear axis: X axis) 4. The workpiece 1 rotates in the workpiece rotation direction (rotation axis: A axis) 5a, 5b, 5c.

  There is a known technique in which the upper wire guide 9 is moved relative to the lower wire guide by a U-axis and V-axis motor not shown in FIG. 1 to tilt the wire electrode 2. In the embodiment of the present invention, there is no problem in tilting the wire electrode 2. Even when the wire electrode 2 is tilted, the radius of rotation at the workpiece machining point may be specified.

  FIG. 4 is a diagram for explaining that the rotation radius Ra at the upper workpiece machining point 8a may be different from the rotation radius Rb at the lower workpiece machining point 8b depending on the inclination direction of the wire electrode 2. FIG. In this case, of the upper and lower workpiece machining points, you may specify the radius of rotation that places importance on machining accuracy. If the required machining accuracy is equivalent, the rotation at the upper and lower workpiece machining points By specifying the radius value of the radius as the rotation radius, the same processing accuracy can be obtained at the upper part and the lower part.

FIG. 5 is a flowchart for explaining an algorithm of processing according to the present invention. Hereinafter, it demonstrates according to each step.
[Step SA100] One block of the machining program is read.
[Step SA101] It is determined whether or not the command block specifies the initial turning radius. If the command block is a command block, the process proceeds to Step SA102. If the command block is not a command block, the process proceeds to Step SA104.
[Step SA102] The initial turning radius R is read.
[Step SA103] The initial turning radius R is substituted into the current turning radius Ra.
[Step SA104] The movement amount X of the linear axis and the movement amount A of the rotation axis are acquired.
[Step SA105] The current rotation radius Ra is substituted into the rotation radius Rs at the start point.
[Step SA106] It is determined whether or not there is a turning radius command. If there is a turning radius command, the process proceeds to Step SA107, and if there is no command, the process proceeds to Step SA108.
[Step SA107] The rotation radius R is substituted into the rotation radius Re at the end point.
[Step SA108] The current turning radius Ra is substituted into the turning radius Re at the end point.
[Step SA109] A value obtained by subtracting the rotation radius Rs at the start point from the rotation radius Re at the end point is substituted into the rotation radius increment Rinc.
[Step SA110] The movement amount integrated value SUMa is set to 0 as an initial value.
[Step SA111] It is determined whether or not it is a block end point. If it is a block end point, the process proceeds to Step SA116. If it is not a block end point, the process proceeds to Step SA112.
[Step SA112] The command speed Fc is acquired from the machining power supply.
[Step SA113] Fc · X / √ (X ² + (Ra · k · A) ² ) is substituted into the movement amount ΔX. Also, Fc · A / √ (X ² + (Ra · k · A) ² ) is substituted into the movement amount ΔA. However, k = π / 180 [deg]
[Step SA114] A value obtained by adding the movement amount ΔA to the movement amount integrated value SUMa is substituted into the movement amount integration value SUMa.
[Step SA115] The current turning radius Ra is calculated by Rs + Rinc · SUMa / A.
[Step SA116] The rotation radius Re at the end point is substituted into the current rotation radius Ra.
[Step SA117] It is determined whether or not there is a next block. If there is, the process proceeds to Step SA100, and if there is no next block, the process is terminated.

DESCRIPTION OF SYMBOLS 1 Work 2 Wire electrode 3 Machining groove 7a, 7b Work machining point 8a, 8b Work machining point 9 Upper wire guide 10 Lower wire guide 12 Table 14 X-axis motor 16 Y-axis motor 18 Strut part 20 Rotation drive device 21 Rotation shaft 22 A Axis motor 23 A-axis speed detector 24 A-axis angle detector 25 Work fixing bracket 30 Processing fluid 40 Numerical control device 50 Processing power source

Fc Command speed Fx Linear axis speed Fa Rotary axis speed

Claims (2)

Wire-cut electric discharge machining, in which the workpiece can be moved relative to the wire electrodes stretched by the upper wire electrode guide and the lower wire electrode guide in the axial direction perpendicular to each other, and the workpiece can be rotated. In the numerical controller of the wire cut electric discharge machine that controls the machine according to the machining program,
Storage means for storing a turning radius at a workpiece machining point at an end point of each block of the machining program;
A reading means for reading out the end point in the block to be executed and the turning radius at the workpiece machining point at the end point in the block from the storage means;
Calculation for calculating the rotation radius at the workpiece machining point currently being machined every predetermined period from the rotation radius of the end point of the previous block read from the storage means, the rotation radius of the end point of the block to be executed, and the amount of movement of the rotation axis Means,
Control means for controlling the relative speed between the wire electrode and the workpiece machining point from the turning radius calculated by the calculating means so as to become a command speed;
A numerical control device for a wire cut electric discharge machine, comprising:   The wire cut according to claim 1, wherein the turning radius stored in the storage means is a value obtained by instructing each block in a machining program and analyzing the machining program. Numerical control device for EDM.

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