JPH054121A - Working method in wire-cut electric discharge machine - Google Patents

Abstract

PURPOSE:To provide a working method in the wire cut electric discharge machining which carry out taper cut of a certain shape even at a relatively large taper angle in a relatively simple manner. CONSTITUTION:A center point is provided, and working can be carried out by a program with which a shape determined according to the revolution angle around the center point and the distance in the radial direction can be prepared in a relatively simple manner, and a work is revolved around one rotary shaft 14 for a wire 9 laid between two points, and the revolution speed W of the work and the distance between the rotary shaft 14 and the wire 9 are controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of wire-cutting a shape having a center point and determined by a rotation angle about this point and a radial distance.

[0002]

2. Description of the Related Art Conventionally, a wire-cut electric discharge machine (hereinafter,
In an electric discharge machine), a work is moved in X and Y directions with respect to a wire stretched in the Z-axis direction to perform cutting. The movement in the X and Y directions is the movement of the table (X
Axis, Y axis) and is input to the numerical control device (NC device) of the electric discharge machine. In this case, the curved section of the processed figure is divided into fine two-point intervals (blocks), and the two points are usually connected by straight line or circular interpolation. Therefore, when the curve is delicate, a machining program corresponding to many blocks is used. Need to create. In addition, at the time of taper cutting in which the cut surface of the workpiece is inclined, the inclination angle (taper angle) of the wire with respect to the vertical line orthogonal to the table surface is driven by driving the so-called U and V axes on the upper nozzle side. When creating an inclined surface (for example, a conical surface), even if the inclination angle is the same, the U and V axes must be driven constantly because the direction changes.

Further, when a shape having a center point and determined by a rotation angle about this point and a radial distance is created, when a point symmetric figure is repeated like a gear, the rotation provided in the NC device is provided. It is possible to create a machining program relatively easily by using the and repeat function, but when it is not a point symmetry like an irregular flower shape, it is a kind of rotating figure, but the machining program is very complicated. It takes time and effort to create.

Further, when the cut surface is inclined using the U and V axes, the taper angle depends on the hardness of the wire and the U and V
± 30 ° due to V-axis stroke and machining fluid supply
The degree is limited.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, by wire-cut electric discharge machining, it is possible to relatively easily create a shape having a center point and determined by a rotation angle and a radial distance about this point. It is another object of the present invention to provide a processing method which can perform the taper cutting of this shape relatively easily and can achieve a relatively large taper angle.

[0006]

A work is rotated around one rotation axis with respect to a wire stretched between two points, and the rotation speed of the work and the distance between the rotation axis and the wire are controlled.

[0007]

The structure in which the work is rotated and the rotation speed thereof and the distance between the rotation axis and the wire are controlled enables the machining shape to be created as planar polar coordinates.

[0008]

FIG. 2 shows an essential part of an electric discharge machine 1 for carrying out the method of the present invention, in which a work rotating unit 3 is mounted on a table 2.
Is attached, and the work 4 is attached horizontally in the figure. Further, the upper nozzle 5 is U on the upper surface side of the work 4.
The lower nozzle 7 is attached to the V-axis drive device 6 and is arranged on the lower surface side so that the lower nozzle 7 can be adjusted in vertical position with respect to the lower arm 8. Reference numeral 9 is a wire, and reference numeral 10 is an X-axis servomotor.

The electric discharge machine 1 is different from the conventional one except that the work rotating unit 3 is mounted on the table 2 driven along the X axis and the Y axis, including other configurations. There is no difference. However, in this embodiment, the table 2 is moved only in the X-axis direction.

As shown in FIG. 3, the work rotating unit 3 includes a substrate 11, a Y-direction plate 12, an X-direction plate 13 and a rotary shaft 14.
The Y-direction plate 12 is rotatably supported on the horizontal second support shaft 15 in the X-axis direction of the substrate 11, and the Y-direction plate 12 is horizontally supported by the first support shaft 16 in the Y-axis direction. The X-direction plate 13 is rotatably supported, and is wholly fixed to the upper surface of the table 2 with bolts 17.

The rotating shaft 14 has a base portion axially supported by a bearing 18 in the Z-axis direction perpendicularly to the upper surface of the X-direction plate 13, and a tip end portion thereof is provided with a flange 19 and a screw portion 20 to mount the work 4 thereon. A pinion 22 for a worm gear is fixed to the central portion of the pinion 21. Reference numeral 23 is a servo motor for rotating the work, which is horizontally fixed to the upper surface of the X-direction plate 13 via a stay, and a worm gear 24 fixed to the output shaft thereof meshes with the pinion 22.

A first tilt adjusting mechanism 25 for tilting the X-direction plate 13 in the X-axis direction about the first support shaft 16 is formed between one end of the X-direction plate 13 and the Y-direction plate 12. There is.
The first tilt adjusting mechanism 25 has a Y-direction on one end of the X-direction plate 13.
A ball nut 27 mounted by a small shaft 26 in the axial direction, and a ball screw 2 having a pinion 28 fixed to the upper end.
9. A worm gear 30 screwed to the pinion 28 and a first tilt servomotor 31 for driving the worm gear 30 are provided, and a ball screw 29 is screwed to the ball nut 27 and the lower end thereof is rotated to the upper surface of the Y-direction plate 12. Further, the worm gear 30 and the servo motor 31 are fixed to the upper surface of the Y-direction plate 12 via a stay, and the worm gear 30 is meshed with the pinion 28. Therefore, when the first tilt servomotor 31 is driven, the ball screw 29 rotates via the pinion 28, the ball nut 27 moves up and down, and the X direction plate 19 moves around the first support shaft 16 in the X axis direction. Tilt in the direction.

A second tilt adjusting mechanism 32 having the same structure as that described above is also provided between one end of the Y-direction plate 12 and the substrate 11, and the Y-direction plate 12 is centered around the second support shaft 15 so that the Y-direction plate 12 has the Y-axis. It is designed to be tilted in the direction. In FIG. 3, only the position of the ball screw 33 is shown, and the illustration of other components is omitted.
The ball screw 33 is driven by the second tilt servomotor 34 (FIG. 1). Therefore, when the second tilt servomotor 34 is driven similarly to the above, the Y-direction plate 12 is tilted in the Y-axis direction.

Reference numeral 35 is a watertight cover, and the portion where the rotary shaft 14 projects has a bellows structure 35 to allow the rotary shaft 14 to incline.

The structure of the above embodiment is schematically shown in FIG. 1, and the servomotors 23, 31 and 34 are controlled by the NC device provided in the electric discharge machine 1. The other controlled objects by the NC device are the same as the conventional ones. This electric discharge machine 1
The wire cutting method by
It is carried out by moving the table 2 in the X-axis direction while rotating the work 4 attached to the mounting portion 21 of the rotary shaft 14. As a result, a shape having a center point as shown in FIG. 4 and determined by the rotation angle about this point and the radial distance is processed. For this purpose, the machining program to be input to the NC device may be created in the plane polar coordinate system in which the rotation angle ω of the work 4 by the servo motor 23 and the X-direction movement amount χ by the X-axis servo motor 10 are used as the position data. In addition, the interpolation curve between two points in one block is smoothly formed. Both the rotation and the movement of the work 4 in the X-axis direction are continuously or intermittently performed. Also, the rotation speed ω of the work piece 4 is changed accordingly as a function of the distance between the rotation shaft 14 and the wire 9, and the work piece 4 with respect to the wire 9 in the electric discharge machining position is changed.
It is preferable to always keep the speed of 1 constant.

When the cut surface is a tapered surface, the first
Drives the tilt servo motor 31 to rotate the work shaft 1
4 is tilted in the X-axis direction to bring the rotating shaft 14 and the wire 9 into a non-parallel state where they intersect each other. As a result, the contact angle θ between the wire 9 stretched in the Z-axis direction and the work 4 (the inclination angle of the rotary shaft 14) is changed, and the desired inclination can be imparted to the cut surface. As a result, not only a truncated cone shape, but also a bevel gear or a bevel gear shape based on this, in which a centripetal inclined surface is added to a gear-shaped cut surface as shown in FIG. 4, can be processed. At this time,
When the work 4 is rotated with the angle θ fixed, the cut surface is formed by inclined surfaces having the same angle, but if the angle θ is changed in the middle, the inclination of the cut surface can be partially changed.

Note that the angle θ is set as data in the machining program, and because the rotary shaft 14 of the workpiece 4 is inclined, the actual machining position is ± L · cos θ by X when the substantial length of the rotary shaft 14 is L. A process of correcting the amount of axial displacement is necessary. Further, since the rotating shaft 14 and the wire 9 are in a non-parallel state, the speed of the work 4 with respect to the wire 9 is different in the thickness direction of the work 4, so it is necessary to match the processing speed to the side with the higher speed. .

This is the same as machining the U-axis of the upper nozzle 5 by moving the U-axis of the upper nozzle 5 back and forth by the U / V driving device 6 except for the above-mentioned correction, but combining both. As a result, the taper angle can be increased, and a taper angle of 30 ° or more is possible. Further, in addition to the rotation of the work 4 and the inclination of the rotary shaft 14 and the movement in the X-axis direction, a cutting process in which the wire 9 is inclined in the V-axis direction by the U / V drive device 6 is possible.

The second tilt servomotor 34 is driven to tilt the rotary shaft 14 of the work 4 in the Y-axis direction, and the rotary shaft 14 is rotated.
And the wire 9 are twisted by an angle γ in a non-parallel state, and while maintaining this state, the workpiece 4 and the movement in the X-axis direction are combined to machine the helical gear or the helical gear as shown in FIG. Processing to obtain a gear shape (called helical processing) is possible. If the angle γ is changed during the processing, the parts corresponding to the gear teeth are curved. In this case, the actual machining position is displaced in the Y-axis direction by ± L · cosγ when the substantial length of the rotary shaft 14 is L, and therefore a process for correcting this is necessary. This is similar to the processing in which the V-axis of the upper nozzle 5 is moved to the left or right by the U / V drive device 6 or is processed while moving, but by combining both, the inclination of the part corresponding to the gear tooth is tilted. The angle can be increased.

The above is an embodiment, and the means for inclining the rotary shaft 14 of the work 4 in the X-axis direction and the Y-axis direction is not limited to that shown in the drawings. Further, the shape processed by the method of the present invention is not only a point-symmetrical shape but also a general shape having a center point and determined by the rotation angle about this point and the radial distance.

Further, when the table 2 is also moved in the Y axis direction, the wire 9 can be moved back and forth with respect to the rotary shaft 14 of the work 4 in the state of being shifted in the Y axis direction in FIG. It is possible to obtain machined shapes having different angles with respect to the radial direction of the tooth profile.

[0022]

EFFECTS OF THE INVENTION It is easy to create a machining program having a shape having a center point and determined by a rotation angle about this point and a radial distance. The required curved surface is formed smoothly. When the rotation axis of the work is made non-parallel to the wire, the taper angle in taper machining and the inclination angle of the gear tooth equivalent part in the helical gear shape can be increased.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a processing method of the present invention.

FIG. 2 is a front view schematically showing a main part with a part thereof broken away.

FIG. 3 is a front view of the work rotating unit (partially cut away).

FIG. 4 is a plan view showing a processed state.

FIG. 5 is a front view showing a state of taper processing.

FIG. 6 is a front view showing a state of helical processing.

[Explanation of symbols]

2 table 3 work rotating unit 4 work 6 U / V drive 9 wire 10 X-axis servo motor 23 work rotating servo motor 25 first tilt adjusting mechanism 31 first tilt servo motor 32 second tilt adjusting mechanism 34 second Tilt servo motor

Claims (3)

[Claims] 1. A center point is provided by rotating a workpiece around a single rotation axis with respect to a wire stretched between two points and controlling the rotation speed and the distance between the rotation axis and the wire. A machining method for a wire-cut electric discharge machine that performs machining of a shape that is determined by the rotation angle around this point and the radial distance. 2. The processing method according to claim 1, wherein the rotating shaft of the work and the wire stretched between two points are arranged non-parallel to each other. 3. The machining according to claim 2, wherein the angle formed by the wire stretched between the rotation axis of the workpiece and the two points is controlled during machining, and the degree of non-parallelism is changed. Method.