JPS629821A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To enable stable machining and to improve the machining speed by setting the relative feeding speed between an electrode and a work in perpendicular direction against the cutting feed direction higher than specific level thereby facilitating removal of machining chips and foam while improving the fluid removing effect. CONSTITUTION:Cutting feed under discharge machining is applied in X and Y axes through motors 10, 11 as well as in Z-axis through a motor 12 to perform machining while controlling the rotary speed through driving of motor 13 to specific level. When bringing the relative feeding speed between the electrode and the work in perpendicular direction with the cutting feed direction or the feeding speed of motor 13 higher than the optimal level 2m/min, machining chips and foam produced in the machining gap can be removed well and discharged quickly through agitating function caused by high relative speed resulting in safe machining with high machining speed.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention provides a method for guiding a wire (including band-shaped) electrode into a desired processing shape by a guide and moving the electrode formed by the wire electrode onto a workpiece. This invention relates to electrical discharge machining in which machining is performed by repeatedly applying pulsed discharge to opposing machining gaps.

[Prior art]

The present inventor has proposed an electrical discharge process in which a wire electrode is guided into a required machining shape by a guide and moved, and an electrode is formed by the wire electrode. A processing device was proposed. According to this electrode, the wire electrode that forms the machining surface is constantly moved and renewed, so that electric discharge machining can be performed with virtually no electrode wear and no deformation due to wear and tear.

According to various experiments on the machinability of the electrode formed by the wire electrode, it has been found that machining is performed by applying a relative feed in a direction almost perpendicular to the cutting feed applied between the electrode and the workpiece, but the feed rate is It was found that the machining speed changes depending on the control, and a rapid increase in the machining speed can be expected at a speed of about 2 m/1 n.

[Means for solving problems]

Therefore, in the present invention, the speed is set at least 2 m/m in a direction substantially perpendicular to the cutting feed given between the electrode and the workpiece.
It is characterized by processing by applying a relative feed of in. or more.

(Example) The present invention will be explained below with reference to an embodiment of the drawings.

Reference numeral 1 denotes a guide for forming a processed surface of the electrode, which forms a guide surface of a desired shape, and guides and moves the wire electrode 2 along the guide surface. 3 is a reel for supplying the wire, 4 is a take-up reel, 5 is a brake provided on the supply reel 3 side, 6 is a take-up row on the take-off reel 4 side, and the wire 2 moving on the guide 1 is fixed by both of them. Move with tension and speed. 1 is a spindle that supports an electrode composed of a guide 1, a wire 2, a reel 3.4, etc.; 8 is a workpiece; 9 is a processing table; 10, 11.12
13 is a drive motor that provides feed, 13 is a motor that rotates a spindle, 14 is an NG control device, and 15 is a processing power source.

In the above process, the wire electrode 2 moving through the guide 1 faces the workpiece 8 for processing. The guide surface forms a desired electrode processing surface, and a wire electrode 2 is supplied to this guide 1 from a reel 3 and wound onto the other reel 4 through the guide. The wire electrode 2 is moved along the guide 1 with a predetermined tension and speed by a brake 5 and a take-up roller 6 on the way. Pulses are applied between the electrode and the workpiece 8 from a machining power source 15, machining fluid is supplied from a nozzle (not shown) or by forming a jet hole in the guide 1, and submerged pulse discharge is repeated to perform electrical discharge machining. . The cutting feed in the opposing Z-axis direction is performed by driving the motor 12, and electrical discharge machining is performed while being rotated by the motor 13 corresponding to this Z-axis feed. The wire electrode 2 moving through the guide 1 moves linearly, and can form a surface of a predetermined shape on the workpiece 8 by rotation by a motor. Motor 1 feeds the cut during machining.
2 drive not only in the z-axis direction but also motor 10,1
1 in the X@ and Y-axis directions, and in relation to this feed, the rotational speed driven by the motor 13 is controlled to a required speed for machining. For example, if the Z-axis cutting feed of the motor 12 is increased, the rotational speed by the motor 13 will not be slowed down; on the other hand, if the Z-axis transport is slowed down, the rotational speed can be increased.

This is the same even when machining to a predetermined depth in the Z-axis direction and then applying cutting feed (approaching feed) in the X-axis and Y-axis directions. If so, the rotational speed for machining must be lowered, and the rotational speed can be increased by making the depth of cut shallower (lowering the feed rate).

Therefore, the results of an experiment to determine the optimum value of the relative feed speed between the electrode and the workpiece (rotational speed by the motor 13 in the embodiment of FIG. 1) applied in the orthogonal direction in accordance with the cutting feed are as shown in FIG. It is. This is a graph diagram when processing 855C material while moving a Bs wire with a wire diameter of 0.3 mmφ as a guide at a speed of 3 numin. Processing conditions are Ip=700A, τon=1.2
．． czs, and water with a specific resistance of 5×10 4 Ωcm was used as the machining fluid. As can be seen from this graph, there is a rapid change in the machining speed when the relative feed speed applied between the electrode and the workpiece is approximately 1 to 3 m/min, and approximately 2n+
By controlling the speed to about /min or more, a remarkable effect can be seen in improving the processing speed. The solid line indicates the case where the processing liquid is supplied from one side when processing a plate-shaped workpiece, and the dotted line indicates the case where the processing liquid is supplied from both sides.

This improvement in machining effect is achieved by increasing the relative feed rate to an optimal value of 21/mi.
One of the reasons seems to be that by setting it to n or more, processing chips, bubbles, etc. that occur in the processing gap are better removed. In order to increase the relative feed speed, the depth of cut must be reduced (shallowed) accordingly, and the shallow depth of cut makes it easier for machining chips to escape, and the high relative movement speed causes disturbance effects, etc. With the addition of the

Note that the relative feed between the electrode and the workpiece perpendicular to the cutting depth is not limited to rotation of the electrode side, but may also rotate the workpiece. For example,
) Feed the cut to the Z-axis and move the X by motors 10 and 11.
-Y plane feeding may be used.

In addition, even when the wire electrode 2 is moved and moved by passing it between guides that maintain an interval, the wire electrode between the guides is opposed to the workpiece, cutting is performed in the opposite direction, and relative feeding is applied in the direction orthogonal to the workpiece. The processing speed can be increased by setting the relative feed rate to 21n/l1lin or more.

〔Effect of the invention〕

As described above, in the present invention, a wire electrode is guided into a desired shape by a guide, and a pulsed discharge is repeatedly applied to the gap between the electrode formed by the moving and traveling wire electrode and facing the workpiece. Because of this, electrical discharge machining can be performed with virtually no electrode consumption, and highly accurate machining can be performed efficiently. The present invention provides a relative feed that is applied in a direction substantially orthogonal to the cutting feed that is applied between the electrode and the workpiece at a speed of at least 2 m/min.
Since the depth of cut has been reduced in order to be able to feed at a speed of more than 1.5 in., the machining chips and generated air bubbles can easily escape, increasing the flow removal effect along with the machining fluid, allowing stable machining, and high relative movement speed. This increases the release of arcs and short circuits and the movement of the tIl electric point, and as a result, the machining speed can be significantly increased.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention, and FIG. 2 is an experimental graph diagram. 1......Guide 2...Wire electrode 3.4...Reel 5...Brake 6... ...... Take-up roller 8 ... Workpiece 10.11, 12.13 ... Motor 14
・・・・・・・・・NC device 15 ・・・・・・・・・When powering for processing
−1

Claims (1)

[Claims] In an electrical discharge machining method, a wire electrode is guided into a desired shape by a guide, and an electrode formed by the moving wire electrode is machined by repeatedly applying pulse discharge to a machining gap in which the electrode formed by the wire electrode is opposed to a workpiece. An electric discharge machining method, characterized in that machining is performed by applying a relative feed of at least 2 m/min or more in a direction substantially perpendicular to the cutting feed applied between the workpiece and the cutting feed.