JP2514954Y2 - Wire electric discharge machine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention damages a head by collision between a nozzle portion provided on a head for guiding and supporting a wire electrode and a work or a table on which the work is mounted. The present invention relates to a wire electric discharge machine equipped with a device for preventing this.

[Conventional technology]

The wire electric discharge machine is for machining a work by electric discharge while moving the wire electrode and the work relatively, and a work or a table having the work mounted on a head which guides the wire electrode during the relative movement. If it is accidentally collided with the wire electrode, proper tension will be applied to the wire electrode in the head, and the wire guide guiding and supporting the wire electrode will be seriously damaged. As a result, the wire electrode may be displaced, the proper tension may not be maintained, the machining accuracy may be deteriorated, or the wire electrode may be easily broken. Therefore, conventionally, a bare conductive wire for contact detection is usually disposed around the end of the head where contact occurs, and the head or head is electrically detected when a work or a table is in contact with the conductive wire. To prevent the work or table from colliding with each other.

[Problems to be solved by the device]

However, in the method of disposing the conductive wire, the movement of the work and the table is stopped at a position farther than the position where the work and the table are in contact with each other. There is a problem of doing. There is also a problem that the drop of the processed piece cut from the workpiece cannot be detected.

Therefore, in order to solve such a problem, the present invention has a device capable of not only the contact detection by the movement of the workpiece or the table in the horizontal plane but also the vertical contact detection without reducing the processing area. The purpose of the present invention is to provide a wire electric discharge machine.

[Means for solving the problem]

In view of the above object, the present invention is, in detail, a wire electric discharge machine that performs electric discharge machining of the work while moving the wire electrode and the work relative to each other, and has a wire guide that guides and supports the wire electrode. Heads provided on the upper and lower sides of the work, and openings for adjusting the position in the vertical direction with respect to the head so as to surround the wire guide, and openings for ejecting a machining liquid to the electric discharge machining unit, and When the work or table collides with the work due to the relative movement of the wire electrode and the work, the wire guide is made of a deformable hollow body that can easily absorb impact by deformation so as not to damage the wire guide, and imparts conductivity to the entire outer surface. And a detection circuit for detecting contact between the work or the table and the surface of the nozzle. To provide a wire electric discharge machine according to claim.

[Action]

The nozzles attached to the upper and lower heads on the side facing the work are used as conductive contact detection means to detect that the work or table comes into contact with the head along with the detection circuit in three dimensions of X, Y, and Z. Direction can be detected,
Since the nozzle portion, which is the contact detection means, is an easily deformable hollow object that can easily absorb impact due to deformation, only the nozzle portion is damaged by the collision of the table or the like and does not affect the head body.

[Embodiment] The present invention will be described in more detail based on an embodiment shown in the accompanying drawings.

Referring to FIG. 4, an electric discharge machining unit provided in a machine body 8 of the wire electric discharge machine is shown.
A table 14 on which a work is attached is provided, and an upper head 16 and a lower head 18 for guiding and supporting the longitudinal running of the wire electrode 10 are provided above and below the table 14. The table 14 is formed in a plane so as to be movable in two directions of an X axis and a Y axis which are orthogonal to each other as shown in the drawing, and the work is relatively moved to the wire electrode 10 traveling in the vertical direction. The desired shape is obtained by moving the wire in the axial direction to generate an electric discharge between the wire electrode and the wire electrode through a minute gap to allow the electric discharge machining to proceed. Here, the wire electrode 10 is generally guided to an electric discharge machining unit from a wire electrode supply bobbin (not shown) serving as a wire electrode supply source through various guide rollers and tension rollers in a state where a constant tension is applied. The roller 20 represents one of the guide rollers, and the wire electrode 10 passing through the guide roller 20 reaches above the upper head 16 through the wire electrode supply roller mechanism 22. Directly above the upper head 16, a wire electrode guiding device 24 is provided, which guides a new wire electrode end to the upper head 16 when the wire electrode 10 is broken in the electric discharge machining unit 12, and the wire electrode 10 is guided. This is a device that enables automatic wire connection, and is an essential component of recent wire-cut electric discharge machines. The upper head 16
Is generally provided so as to be vertically movable toward and away from the lower head 18, and can be moved away from the lower head (Z-axis operation). By turning the handle 6, the upper head 16 is vertically moved integrally with the wire electrode guiding device 24. It moves.

The wire electrode 10 passes through the upper head 16 with a small gap from the work, and is guided by the lower head 18 held by the base 26a at the tip of the arm 26 fixed to the machine body 8, and thereafter. For example, in the illustrated example, the winding roller or the wire electrode collection box is bent right below the lower head 18 at a substantially right angle, and is provided at a proper position of the machine body 8 through an appropriate guide roller, wire electrode winding roller, or the like, which is not illustrated. Will be collected. The electric discharge machining unit 12 is surrounded by an appropriate cover 28 which prevents the machining fluid from scattering.

In the wire cut electric discharge machine with the above configuration,
The work W is machined while moving the table 14 on which the work W (Fig. 1) is attached to the wire electrode 10 in the X and Y directions in the horizontal plane. Contact the upper head 16 or the lower head 18,
Or it may collide. If a collision occurs, the heads 16 and 18 will be damaged or their exact mounting positions will be displaced, which will hinder the smooth running of the wire electrode 10.

Before the upper head 16 or the lower head 18 is damaged by the collision, it is necessary to detect the collision and prevent the head itself from being damaged. In the present invention, the contact at the start of the collision is detected by the nozzle portion 30 provided at the end portion of the head, and the movement of the table 14 or the like is electrically stopped to destroy the nozzle portion 30, but the head main body portion is destroyed. It is designed to prevent damage. That is, the upper head 16 and the lower head 18 are nozzle portions for ejecting the machining liquid to the electric discharge machining portion at the end portions of the heads facing each other, that is, the head end portions facing the work W, respectively. When the work W or the table 14 comes into contact with and collides with the lower head 18 (the same applies to the upper head 16) as shown in FIG. 1, most of them are nozzle parts. Occurs between 30 and 30. Therefore, by providing the nozzle portion 30 with a contact detection function and further with an impact absorbing function, even if the nozzle portion 30 is damaged, the head 18 itself is not damaged.
Further, even when the work piece cut off by the wire electrode 10 falls down, the work piece also falls onto the upper surface of the nozzle portion 30, and the fallen work piece usually has an upper portion of the work piece W above the work piece W. Since the rest portion leans against the remaining portion, the nozzle portion 30, the work W and the table 14 are electrically connected to each other through the work piece.

First, in order to give the nozzle portion 30 shock absorbing properties, for example, it may be made of a resin material or hard rubber that is more easily deformed than metal. Further, in order to have conductivity, the resin material is, for example, carbon fiber-containing fluorine resin, carbon fiber-containing acetal resin, or conductive phenolic resin, or the outer surface of the resin nozzle portion. There is a method of applying metal plating on the top. For plating, for example, there is a method in which ABS resin is first copper-plated, and nickel-chromium plating is further applied thereon. In this case, nickel / chromium plating is performed to improve the corrosion resistance against the electrolytic corrosion action. FIG. 2 shows an example thereof in a sectional view. A base portion 30a of the nozzle portion 30, for example, a conductive metal plating layer 30b made of ABS resin and having copper and nickel-chromium plating on its outer surface is formed. It is provided. By configuring the nozzle portion in this way and further providing an electric circuit described later shown in FIG. 3, when the work W or the table 14 collides, the initial contact is electrically detected and the table 14 or the like is detected. The influence of overrun in which a command for immediately stopping the movement is transmitted and the table or the like moves until it completely stops is that only the nozzle unit 30 is damaged. That is, the nozzle portion 30 is provided with a screw portion 30c attached to the main body portion of the head 18 on the outer periphery of the lower portion thereof, and is attached to the head main body portion to form the head 18 together, but the nozzle portion 30 itself is deformed. Since it is easy, an impact such as a table cannot be transmitted to the head main body through the screw portion 30c. Inside the nozzle part 30, a wire guide 32 is provided which not only gives an appropriate tension to the wire electrode 10 but also maintains the position of the wire electrode accurately, but since the impact is not transmitted to the head main body part, the wire guide 32 is provided. The guide 32 also does not suffer damage. Therefore, troubles such as displacement of the wire electrode, deviation of tension, disconnection, etc. do not occur.
In addition, the easily deformable nozzle portion 30 receives the shock in the vertical direction Z when the processed piece of the wire W is dropped, so that the head main body is not affected.

When the nozzle portion 30 is made of a conductive metal, it is necessary to provide a notch as shown by a chain double-dashed line 30e in FIG.
Due to the presence of the notch 30e, even if the table 14 or the like collides with the upper portion of the nozzle portion 30, the nozzle portion 3 is located at the notch 30e.
0 is damaged and the head body is not damaged at all. Further, the contact state at the time of collision is immediately detected because the nozzle unit 30 itself is a conductive metal. Note that such a notch 30e may be applied to the nozzle portion 30 made of a resin material or hard rubber.

A detection circuit used in the above contact detection will be described with reference to FIG. Nozzle part while using EDM
AC voltage is applied between 30 and table 14 and diode 34
Is converted to a direct current through the integrator circuit 36, smoothed by the integration circuit 36, and compared with a desired reference potential created by the variable resistor 40 and the fixed resistor 44 by the comparator 42. When the nozzle unit 30 and the table 14 come into contact with each other, a signal to that effect is output from the comparator 42, which is input to the NC device 48 to cause an emergency stop of the feed movement of the table 14. The resistor 46 is provided to stabilize the reference voltage. In addition, it is the nozzle unit 30 that applies an AC voltage between the nozzle unit 30 and the table 14.
This is to prevent electric corrosion such as.

[Effect of device]

As is apparent from the above description, according to the present invention, unlike the conventional detection wire, the contact with the table or the like is detected by the nozzle portion itself having a two-dimensional or three-dimensional expansion, so that detection is impossible. There is no special area and it can be detected reliably. Therefore, even if the processed piece cut from the work falls, the processed piece is received by the nozzle portion, and the drop of the processed piece can be detected. Also,
The nozzle part forms a part of the head, but is easily deformable, so that it does not damage the head body part. Further, since the detection wire is not provided around the head and the contact is detected by a part of the head, the movement of the table is not particularly limited and a sufficient movement amount is secured.

[Brief description of drawings]

FIG. 1 is an enlarged side view showing a nozzle portion forming a part of a head according to the present invention together with a table, FIG. 2 is a vertical sectional view of the nozzle portion, FIG. 3 is a detection circuit diagram for contact detection, and FIG. FIG. 3 is a perspective view of a main part of a wire electric discharge machine. 10 ... Wire electrode, 14 ... Table, 16 ... Upper head,
18 ... Lower head, 30 ... Nozzle part, 30b ... Metal plating layer, 30e ... Notch, W ... Work.

Claims (2)

(57) [Scope of utility model registration request] 1. A wire electric discharge machine for performing electric discharge machining of a work while moving the wire electrode and the work relative to each other, comprising a wire guide for guiding and supporting the wire electrode.
Heads provided respectively above and below the work; and openings that are screwed so as to be vertically adjustable with respect to the heads so as to surround the wire guides, and have openings for ejecting a machining liquid to the electric discharge machining unit, and At the time of collision between the work or the table due to the relative movement of the wire electrode and the work, the wire guide is made of a deformable hollow body that is easy to absorb impact by deformation so as not to damage the wire guide, and has conductivity over the entire outer surface. A wire electric discharge machine comprising: a nozzle formed so as to hold the workpiece; and a detection circuit for detecting contact between the work or table and the surface of the nozzle. 2. The detection circuit applies an AC voltage between the work or table and the nozzle.
Wire electric discharge machine described in.