JP2704685B2 - Machining method in wire cut electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a shape having a center point, which is determined by a rotation angle and a radial distance around the center point, by wire cutting.

[0002]

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

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

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

[0005]

SUMMARY OF THE INVENTION The present invention relates to a machining method using wire cut electric discharge machining, which can relatively easily create a shape having a center point and determined by a rotation angle and a radial distance around the center point. It is another object of the present invention to provide a processing method capable of performing a taper cut of this shape relatively easily and up to a relatively large taper angle.

[0006]

The work is rotated about 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 . Also, for the wire stretched between two points at the same time
Tilt the rotation axis of the work. In addition, between two points
Tilt the wire stretched to the rotation axis of the workpiece
Sometimes.

[0007]

The structure in which the work is rotated and the rotation speed and the distance between the rotation axis and the wire are controlled enables the machining shape to be created as planar polar coordinates. work
Configuration that tilts the axis of rotation increases the running resistance of the wire
Taper processing without causing
You.

[0008]

FIG. 2 shows a main part of an electric discharge machine 1 for carrying out the method of the present invention.
Are attached, and the work 4 is attached horizontally in the figure. In addition, the upper nozzle 5
The lower nozzle 7 is disposed on the lower surface side of the V-axis driving device 6 so as to be vertically adjustable with respect to the lower arm 8. Reference numeral 9 denotes a wire, and reference numeral 10 denotes an X-axis servomotor.

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

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

The rotary shaft 14 has a base vertically supported on the upper surface of the X-direction plate 13 by a bearing 18 in the Z-axis direction, and has a front end provided with a flange 19 and a screw portion 20 for mounting the work 4. A pinion 22 for a worm gear is fixed to a central portion at a portion 21. Reference numeral 23 denotes a work rotating servomotor fixed horizontally on the upper surface of the X-direction plate 13 via a stay, and a worm gear 24 fixed to an output shaft of the servomotor meshes with the pinion 22.

A first tilt adjusting mechanism 25 for tilting the X-direction plate 13 in the X-axis direction around the first support shaft 16 is provided between one end of the X-direction plate 13 and the Y-direction plate 12. I have.
The first tilt adjusting mechanism 25 is provided with one end of the X-direction
A ball nut 27 attached by an axial small shaft 26, 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 inclined servomotor 31 for driving the pinion 28. A ball screw 29 is screwed to a ball nut 27, and the lower end thereof is turned on the upper surface of the Y-direction plate 12. The worm gear 30 and the servomotor 31 are fixed to the upper surface of the Y-direction plate 12 via stays, and the worm gear 30 is engaged with the pinion 28. Therefore, when the first tilt servo motor 31 is driven, the ball screw 29 rotates through the pinion 28, the ball nut 27 moves up and down, and the X-direction plate 19 is moved about 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 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 rotated about the second support shaft 15. It is made to incline in the direction. In FIG. 3, only the position of the ball screw 33 is shown, and illustration of other components is omitted.
The ball screw 33 is driven by a second tilt servo motor 34 (FIG. 1). Accordingly, when the second tilt servo motor 34 is driven as described above, the Y-direction plate 12 is tilted in the Y-axis direction.

Reference numeral 35 denotes a watertight cover, and a portion from which the rotating shaft 14 protrudes has a bellows structure 35 to allow the rotating shaft 14 to be inclined.

FIG. 1 schematically shows the configuration of the above embodiment. The servo motors 23, 31, and 34 are controlled by an NC device provided in the electric discharge machine 1. Other control targets by the NC device are the same as those in the related art. This electric discharge machine 1
The method of wire cutting by the servo motor 23
The table 2 is moved in the X-axis direction while rotating the work 4 attached to the mounting portion 21 of the rotary shaft 14 with the rotation. Thus, a shape having a center point as shown in FIG. 4 and determined by a rotation angle and a radial distance around the center point is processed. For this purpose, the machining program to be input to the NC device may be created in plane polar coordinates using the rotation angle ω of the workpiece 4 by the servomotor 23 and the movement amount 移動 in the X direction by the X-axis servomotor 10 as position data. And an interpolation curve between two points in one block is formed smoothly. The rotation of the work 4 and the movement in the X-axis direction are both performed continuously or intermittently. The rotation speed ω of the workpiece 4 is changed correspondingly as a function of the distance between the rotating shaft 14 and the wire 9 so that the workpiece 4 with respect to the wire 9 at the electric discharge machining position is changed.
It is preferable to keep the speed constant at all times.

When the cut surface is a tapered surface, the first
The tilt servo motor 31 is driven to rotate the rotation axis 1 of the work 4.
4 is tilted in the X-axis direction so that the rotating shaft 14 and the wire 9 intersect in a non-parallel state. Thus, the contact angle θ between the wire 9 stretched in the Z-axis direction and the work 4 (the inclination angle of the rotating shaft 14) is changed, and a desired inclination can be given to the cut surface. Thereby, not only the truncated cone shape but also a bevel gear or a bevel gear shape based on the truncated conical shape in which a centripetal inclined surface is added to a cut surface in a gear shape as shown in FIG. 4 can be processed. At this time,
When the work 4 is rotated while the angle θ is fixed, the cut surface is formed by an inclined surface having the same angle. However, when the angle θ is changed in the middle, the inclination of the cut surface can be partially changed.

The angle θ is set as data in the machining program, and the actual machining position is ± L · cos θ when the actual length of the rotating shaft 14 is L because the rotating shaft 14 of the work 4 is inclined. Processing for correcting the amount of displacement in the axial direction is required. In addition, 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 that it is necessary to match the processing speed to the side where the speed is higher. .

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

The second tilt servo motor 34 is driven to tilt the rotary shaft 14 of the work 4 in the Y-axis direction.
And the wire 9 are twisted by an angle γ in a non-parallel state. When this state is maintained and processing is performed by combining rotation of the work 4 and movement in the X-axis direction, a helical gear or helical gear as shown in FIG. Processing to obtain a gear shape (referred to as helical processing) can be performed. If the angle γ is changed during machining, the portion corresponding to each gear tooth will have a curved shape. In this case, when the actual length of the rotary shaft 14 is L, the actual processing position is displaced in the Y-axis direction by ± L · cosγ, so that a process for correcting this is necessary. This is similar to the case where the V-axis of the upper nozzle 5 is moved to the left or right by the U / V driving device 6 or while moving, but by combining both, the inclination of the portion corresponding to the gear teeth is reduced. 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 the illustrated one. The shape processed by the method of the present invention is not only a point-symmetric shape but also a general shape having a center point and determined by a rotation angle about this point and a 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 FIG. 4 while being shifted in the Y-axis direction. It is possible to obtain machined shapes having different angles of the tooth profile with respect to the radial direction.

[0022]

According to the present invention, there is provided a machining program having a center point and having a shape determined by a rotation angle and a radial distance around the center point.
It is easy to create. The required curved surface is formed smoothly. Tilt the rotation axis of the work or stretch it between two points
Tilt the wire with respect to the rotation axis of the workpiece.
That is, when the rotation axis of the work is made non-parallel to the wire, the taper angle in the taper processing and the inclination angle of the gear teeth equivalent portion in the helical gear shape can be increased. In addition, stretch between two points
The angle of the wire is tapered as normal
Machining, so that the conventional
As a result of tilting the ear, the running resistance of the wire increases,
It is possible to avoid a situation in which ear cutting is likely to occur.

[Brief description of the 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 cut away.

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

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

FIG. 5 is a front view showing a tapered state.

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

[Explanation of symbols]

2 Table 3 Work rotation unit 4 Work 6 U / V drive 9 Wire 10 X-axis servo motor 23 Work rotation servo motor 25 First tilt adjustment mechanism 31 First tilt servo motor 32 Second tilt adjustment mechanism 34 Second Incline servo motor

Claims (3)

(57) [Claims] A work is rotated around a rotation axis with respect to a wire stretched between two points, the rotation speed, the distance between the rotation axis and the wire, and a wire stretched between the two points.
By controlling the inclination of the work rotation axis with respect to the
A machining method in a wire-cut electric discharge machine , which has a center point and performs machining of a shape determined by a rotation angle, a radial distance around the point, and an inclination angle of a rotation axis . 2. The processing method according to claim 1, wherein an inclination angle of a wire stretched between two points with respect to a rotation axis of the workpiece can be adjusted . 3. A control for changing both the inclination of a rotation axis of a work and the inclination angle of a wire stretched between two points during machining.
Processing method according to claim請2 that comprises carrying out.