JPS59209726A - Wire-cut electrical discharge machining method - Google Patents

Abstract

PURPOSE:To prevent the ambient air from entering into a machined gap so that working liquid is easily and surely fed, and as well to prevent wire-break upon electrical discharge machining, by carrying out electrical discharge machining while working liquid is fed from an auxiliary nozzle to a working section on electrical discharge machining. CONSTITUTION:A workpiece 2 is attached, by means of a clamp or the like, to a work table arranged on a cross-slide table. The relative machining feed between a wire-electrode 1 and the workpiece 2 in the horizontal direction perpendicular to the axis of the electrode 1 is carried out such that the table is controlled to be driven by an NC machine or the like in accordance with a predetermined program. Then, in the initial stage of the machining, the machining is carried out as an usual manner, but when it has become possible to insert an auxiliary nozzle 15 into a hole 2a after the progress of machining, the auxiliary nozzle 15 for supplying working liquid is inserted into the hole 2a, and therefore, electrical discharge machining is carried out while the working liquid is always fed to a working section through a machined groove 2b. Thus, wire- break upon electrical discharge machining may be prevented.

Description

[Detailed description of the invention] The present invention relates to a wire cut electrical discharge machining method.

In the wire cut electrical discharge machining method, the wire electrode is usually stretched in a straight line with a moderate tension between the electrode guides of 1 and 2 pieces provided at the ends of two arms.
During processing, the electrode guide is made to run at a constant speed from one electrode guide to the other. The distance between the two electrode guides is usually several tens of σ, and the part to be cut of the workpiece is placed here, and during machining, the wire electrode and workpiece face each other with a small machining gap between them. In addition to supplying liquid, intermittent voltage pulses are applied between both sides to generate electrical discharge, and machining feed is applied to the wire electrode or workpiece by numerical control, etc., thereby machining the contour of the desired shape. be.

The diameter of the wire electrode is usually 0.02 to 0.0.
3. It is an extremely thin wire rod, about the size of a face, and the processing groove of the workpiece cut with it is also extremely narrow, about 0.1 to 1.0 square centimeters.

Therefore, when trying to supply machining fluid from both the upper and lower surfaces of the workpiece to the discharge gap along the wire electrode, the machining gap is in a high temperature state due to discharge, and decomposed gas bubbles from the machining fluid etc. This occurs and forces the machining fluid into the machining groove on the machined side, or rather, it obstructs the supply of machining fluid to the machining gap and around the wire electrode, and the discharge pressure caused by the discharge in the machining gap pushes the wire electrode into the machining groove. The supply machining fluid tends to flow toward the machining groove side from the place where machining is being performed with the machining gap facing the machining groove side and convex in an arc shape. Medium discharge and short circuits are likely to occur, resulting in a small number of disconnections in the wire electrodes. For this reason, various methods of supplying machining fluid have been devised, but even these methods are often insufficient when the workpiece is thick.

The present invention has been made based on the above-mentioned viewpoints, and its objects are to prevent outside air from entering the machining gap, to easily and reliably supply machining fluid evenly, and to prevent wire breakage during electrical discharge machining. It is an object of the present invention to provide a wire cut electric discharge machining method that can prevent this.

The gist of this is that, in addition to the well-known supply of machining fluid to the electrical discharge machining section, it is also possible to insert or connect an auxiliary nozzle for machining fluid supply into the machining start point or the machining groove where machining has been completed. Then, the machining is performed from the auxiliary nozzle toward the machining area where electrical discharge machining is currently being performed.

The purpose is to perform electric discharge machining while supplying machining fluid through the groove.

Hereinafter, the details of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing the main parts of an embodiment of the wire-cut electrical discharge machining method according to the present invention, FIG. 2 is an enlarged perspective view of an auxiliary nozzle for supplying machining fluid, and FIG. 3 is a cutaway in FIG. 1. Line ■−■
FIG. 4 is an enlarged sectional view of the processed portion along the line, and FIGS. 5 and 6 are perspective views showing different embodiments from the above.

In Fig. 1, ■ is a wire electrode, 2 is a workpiece, 3 is an upper machining device supported by an upper arm (not shown), Do, 4
5 is a current-carrying roller, 6 is a brake roller, 7 is a capstan, 8 is a pinch roller, and 9 and 1o are wire electrodes 1 supported on a lower arm (not shown). Guide dies and boat-shaped guides for linearly positioning the rack, 11 and 12 are machining fluid supply pipes for the upper and lower machining heptomes 3.4, 13 and 14 are upper and lower machining fluid supply nozzles, 15 is an auxiliary nozzle, 16 is the hose for the auxiliary nozzle.
Although not shown in the figure, the workpiece 2 is clamped onto a processing table installed on a slide table (not shown), and the wire electrode 1 and the workpiece are The relative machining feed in the horizontal direction perpendicular to the axis of the wire electrode 1 in the figure between the two is given by driving and controlling the cross slide table with an NC device or the like according to a predetermined program.

During electrical discharge machining, the wire 711 pole 1 is pulled out from the electric conduction supply drum (not shown), passed through the energizing roller 5 and the brake roller 6, and then passed through the die skite 9 and the machine start hole previously drilled in the workpiece 2. 2a, and then boat-shaped guide 1
0, a predetermined tension is applied by the capstan 7 and the pinch roller 8, and the material is collected into a collecting device (not shown). In addition, a machining fluid supply device (not shown) supplies machining fluid continuously or alternately from the machining fluid supply nozzle 13.14 under -F via the upper and lower machining fluid supply pipes 11.12, and normally as shown in the diagram. The foreskin of Wire Denshi 1.''
It is supplied as a coaxial machining fluid flow.

At the initial stage of machining, machining is carried out in a conventional manner, but as machining progresses and it becomes possible to insert the auxiliary nozzle 15 into the hole 2a, the auxiliary nozzle 1 for supplying machining fluid is inserted as shown in the figure "C".
51L2a, and electrical discharge machining is performed while constantly supplying machining fluid from the slit hole 13a to the machining part through the machining groove 2b.
This is the start of wire-cut electrical discharge machining of the target mold, etc., and up to this point there has been a quasi-zero stage for installing the auxiliary nozzle 15;
This is called II processing.

Therefore, the auxiliary nozzle 15 for supplying machining liquid is, for example, the second nozzle.
It is recommended to configure it as shown in the figure.

In the figure, 153 is a slit hole, 15b is a flange, and 15C is a rotation-preventing protrusion that fits into the machined groove.

The details of the relationship between the hole 2a through which the wire electrode is inserted at the start of machining, the cut #2'b, and the auxiliary nozzle 15 are shown in FIGS. 3 and 4. The crab start hole 2a in this case is made mechanically with a drill or the like or by electrical machining such as electrical discharge machining, and has a diameter of about 1 to 2 mm compared to the width of the machined groove 2b. Although it is several times larger, it does not interfere with the vertical supply of machining fluid at all.

Although this auxiliary nozzle 15 is of a type inserted into the hole 2a, the nozzle opening may be configured to abut the processed groove 2b and used as shown in FIG. 5.

In the fifth session, 17 is a machining fluid supply hose, 18 is the auxiliary nozzle 1, 19 is a block to which the auxiliary nozzle is attached, 20 is a magnetic chuck fixed to the block 19, and although not shown, the workpiece 2 A device similar to the above is also provided on the lower side of the .

The tip of the auxiliary nozzle 18 is open in contact with the upper and lower surfaces of the workpiece 2, and the machining liquid is supplied from there into the machining #2b. This type of auxiliary nozzle can be easily moved close to the machining area, so it can be used to process long and complex contours.

However, this may not be sufficient if the workpiece 2 has a larger thickness. and auxiliary nozzle 1
The outer diameter of 8 is the width of the machined groove 2b (0.8 in terms of the outer diameter of the wire electrode 1).
The ultra-fine pipe is inserted into the processing groove 2b as an ultra-thin pipe that is the same as or slightly smaller than the diameter (approximately 0.27 tm (approximately 0.27 tm at the time of 2-piece), and is configured to spray and supply processing fluid into the processing groove 2b from the slit on the side of the pipe or the opening of the perforation row, etc. However, when darning, the machining fluid supply pressure must be increased considerably even if the two fluids are supplied into the pipe from both ends of the pipe (both above and below the workpiece) from a long and thin pipe. Pressure (e.g. about 10 kg/an
There is a problem in saying that it has to be O.

In addition, in the above case, the wire electrode is inserted into the machining start hole 2a -ζ
This is an example of starting machining, but not from such a hole.
Mouth 1 of workpiece 2; 6th opening when starting machining from 4 sides
Do as shown.

That is, at this time, the block 21 with the auxiliary nozzle 18 attached to the workpiece 2 is attached to the workpiece 2 by being clamped from the same side by the magnetic head 2o, and the machining fluid supply port 17 and the auxiliary nozzle are sequentially installed from the machining fluid supply device (not shown). Machining is performed by supplying machining liquid through a nostle 18 and a flow path 2ib that matches the shape of the machining start portion of the workpiece 2 in the block 21.

In this case, block 21 contains wire salt at the start of machining.
A notch 213 is provided which also serves as the channel 21b through which the electrode 1 is inserted, and the tip of the auxiliary nozzle 18 and the channel 21b are configured to fit and communicate with this notch 21a. The cut 21a is aligned with the starting point of machining, and the machining is started from there.

Since the present invention is constructed as described above, when the present invention is used, the machining fluid is fully distributed in the cut without a groove layer during electrical discharge machining.
This completely prevents outside air from entering the machining gap and prevents air discharge, and the Soya electrode is also sufficiently cooled, resulting in wire breakage.
] (This can also be prevented, the machining current can be increased, the machining speed can be improved, and thick plates can be cut easily.

The configuration of the present invention is not limited to the above-mentioned embodiments (in general, the shape of the nozzle, the mounting method, etc. are subject to change within the scope of the purpose of the invention). Items whose design can be changed (
However, the present invention encompasses all of them.

It is. For example, the auxiliary nozzle 15 in FIG. 2 has machining fluid supply bosses 16 at both ends as described above. I! It is desirable to configure the nozzle 15 so that the machining liquid is supplied through the nozzle. The slot 21 hole 15a of the opening for spouting the liquid may be one in which round holes are opened at a predetermined interval in the axial direction, or one in which the round holes are opened as they move toward the center of the thickness of the workpiece 2. The opening diameter can be increased by t+f configuration, and even if the present invention supplies machining liquid from the auxiliary nozzles 15 and 18 etc. to the machining section via the injector 11 through the machining section 2b, the machining groove 2b is body 2
Even if the machining groove 2b is not bent much on the way from the open part on the lower surface of -L, the machining liquid may be released to the outside on the way and not reach the machining part. Therefore, in such a case, it is preferable to sequentially close the openings of the machining grooves 2b on the upper and lower surfaces of the workpiece 2 as the machining progresses. A viscous part such as clay may be forced into the upper and lower 1n1 openings of the processing groove 2b, or a permanent magnet or
Various kinds of rubber particles mixed with or embedded with permanent magnet powder, temporary, pieces, etc. are sequentially attracted to cover the openings on the upper and lower surfaces of 1, 2b, or permanent magnets, gono, etc. It is possible to take various measures such as supplying the magnet with an automatic loading means as described in Japanese Unexamined Patent Publication No. 57-x4911-9q so as to close the opening [J of machining l-η2b]. .

[Brief explanation of the drawing]

Figure 1 shows the wire cut electrical discharge machining method according to the present invention.
・Explanatory diagram showing the main parts of the embodiment, FIG. 2 is an enlarged perspective view of an auxiliary nozzle for supplying machining liquid, FIG. 3 is an enlarged sectional view of the machining part along cutting line II-II LM in FIG. 1, FIG. 4 is an enlarged cross-sectional view of the processed portion, and FIGS. 1---------・------Wire electrode 2---
------------One workpiece 2 a ----------
- Cutting hole 3 at the start point of machining - Upper processing head 4 - - - - - - - - Lower processing head 5 -
−−−−・−・−−−One energized roller・6−−−−−−
-------- Brake roller 7------- Capstan 8------, -------- Pinch +1-ra 9---
−〜−−−−1−Guidance die 10−−−−−−−−
--- Boat-shaped guide, ID IL 12 --- One machining liquid supply pipe 13, 14 --- One addition, one wave supply nozzle 1
5, 18---Auxiliary nozzle 16 for supplying machining liquid,
17----------Processing 1 night (line hose 19
．． 21-----Pro 7ri 20------------------- Magnent Chanok Patent Applicant Ji, O- Bucks Co., Ltd. Agent (7524)
Mogami Shotabu

Claims (1)

[Claims] In the wire cut electrical discharge machining method in which a workpiece is cut using a wire electrode, in addition to supplying machining fluid to the machining section using the conventional method, machining fluid is supplied to the starting point of machining or to the machining groove where machining has been completed. The above-mentioned wire cutter is characterized in that an auxiliary nozzle is inserted or connected to the wire cutter, and machining liquid is supplied from the auxiliary nozzle through the machining groove toward the machining area where the electric discharge machining is currently being performed. l- Electrical discharge machining method.