JPH0240454B2 - WAIYAKATSUTOHODENKAKOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire cut electric discharge machining apparatus.

2. Description of the Related Art Wire-cut electric discharge machining apparatuses are widely used for cutting or drilling holes in a workpiece by electric discharge machining using a wire electrode.

However, the conventional wire-cut electrical discharge machining apparatus has a problem in that during electrical discharge machining, as the cutting progresses, the uncut part bends downward due to the weight of the cut part, resulting in deterioration of machining accuracy.

Various proposals have been made to solve this problem. For example, in Japanese Patent Application Laid-Open No. 128296/1987, a method was proposed in which both the cut piece that had been cut by a wire electrode and the part of the workpiece were held together. In this method, two plates of bridging flat permanent magnets are provided to suppress the bending of the cut piece due to its own weight. The material that is being cut or falling off is pressed against a separate material support at any time or position during processing to suppress bending of the cut pieces due to their own weight, and to prevent processing due to bending or disconnection of the wire electrode. It was an attempt to prevent failure.

However, all of these methods and devices have to be carried out manually, resulting in a problem of poor work efficiency. Therefore, in order to solve these problems, the applicant filed a patent application in 1983-
In 035191, a board to which a plurality of permanent magnets can be detachably attached is provided at the leading end of a machining head of a wire-cut electric discharge machining device, and the above-mentioned method is achieved by controlling the current flowing to a plurality of solenoid coils provided on the board. The present invention discloses a device that removes a permanent magnet and clamps and bridges both a cut portion and an uncut portion of a workpiece without manual intervention. However, since the above device does not require manual operation, the efficiency of the work has improved, but when a permanent magnet with high adsorption and holding capacity is used, a large amount of current is applied to the solenoid coil when the permanent magnet is removed. The problem was that it was inefficient.

The present invention has been made in view of the above, and its purpose is to automatically and efficiently clamp both the cut and uncut parts of a workpiece without manual intervention. An object of the present invention is to provide a wire cut electric discharge machining apparatus equipped with a device for preventing cut pieces from falling off, in which a plurality of permanent magnets are arranged so as to be bridged.

The gist of this is that a rotatable base plate to which a plurality of hydraulic or pneumatic fluid pressure cylinders can be attached is provided at a position facing the workpiece at the top of the processing head, and Permanent magnets are detachably held in the pressure cylinders or the substrate, respectively, and a desired one of the permanent magnets held in the plurality of fluid pressure cylinders or the substrate is detached by controlling the fluid pressure cylinders at any time. The object is to sandwich and bridge both the cut and uncut parts of the workpiece.

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

FIG. 1 is an explanatory diagram showing one embodiment of the wire cut electric discharge machining apparatus according to the present invention, FIG. 2 is a bottom view of the cut piece fall-off prevention device as seen from the direction A-A in FIG. 1, and FIG. Explanatory diagram showing the state of the workpiece at the end of machining when the workpiece is machined using the wire cut electric discharge machining apparatus according to the invention, 4th
The figure is an explanatory diagram showing another embodiment.

In FIGS. 1, 2, and 3, 1 is an upper support arm formed by extending from a column at a side end (not shown) toward the upper part of the stage for the workpiece on the bed; 2; is the processing head, 3 is the substrate, 4, 5
is a guide roller, 6 is a current-carrying roller, 7 and 8 are capstans, 9 and 10 are pinch rollers, 11 and 12
is an electrode guide such as a die-shaped or boat-shaped guide,
13 is a wire electrode; 14 is a holding plate having a machining liquid nozzle 14a in its center; 15a, 1
5a is a mounting bolt for attaching the machining head 2 to the lower end of the upper support arm 1; 16 is the machining head 2;
A motor 17 is attached to the motor 16 and rotates the board 3 via a gear; a gear 17 is attached to the motor 16 and rotates as the motor 16 rotates; The gears 19a, 19a provided on the retaining plate 14
A mounting bolt 20 rotatably attaches the substrate 3 to the top of the processing head 2 via a hydraulic cylinder 20 made of a magnetic material such as metal.
a, 20a are pistons, 20b, 20b are piston rods made of non-magnetic material and move as the piston moves up and down, 21, 21 are 4-port, 2-position switching valves, 21a, 21a are solenoid coils, 21b, 21b is a spring; 22 is a hydraulic pump; 23 is an oil tank; 24, 24 are permanent magnets that are detachably held on the lower end surfaces of the hydraulic cylinders 20, 20; 25 is a workpiece; 25
a, 25a is a cutting part of the workpiece 25, 26 is a clamp for fixing the workpiece 25, 27 is a stage, 2
8 is a numerical control device.

During electrical discharge machining, the wire electrode 13 is pulled out at a constant speed from an electrode supply drum (not shown) by capstans 7 and 8 and pinch rollers 9 and 10, and then passed through guide rollers 4 and 5 or energized roller 6. , are supplied to the processing section where the workpiece 25 is placed. In the processing part, the wire electrode 13 is stretched linearly between the electrode guides 11 and 12 with a constant tension, and the workpiece 25 is stretched by the discharge voltage applied between the current-carrying roller 6 and the workpiece 25. A discharge is performed between the

The workpiece 25 is moved via the stage 27 in a direction perpendicular to the stretching direction of the wire electrode 13 by driving a cross slide table (not shown) using the numerical control device 28, and is subjected to the desired processing. Processing is performed according to the contour line. Note that during electrical discharge machining, a machining liquid nozzle 14 is provided on the holding plate 14 in order to remove machining debris generated on the machined part of the workpiece 25 and smooth the electrical discharge machining.
Processing fluid is supplied from a.

In the above-mentioned wire cut electrical discharge machining apparatus, the cut piece fall-off prevention device in which the permanent magnets 24, 24 are arranged so as to sandwich and bridge both the cut portion 25a and the uncut portion of the workpiece 25 is as follows. It has a special structure.

That is, a gear 18 is provided at one end of the substrate 3, and this gear 18 meshes with a gear 17 attached to a motor 16 fixed to the processing head 2. Thus, the mounting bolts 19a, 19a are attached to the top of the processing head 2 via the holding plate 14.
The substrate 3 rotatably attached by the controller 3 rotates as the motor 16 rotates, which is controlled by the numerical control device 28 .

Further, the substrate 3 is provided with at least permanent magnets 24, 2.
A plurality of hydraulic cylinders 20, 20, the parts of which attract 4 are made of a magnetic material, are arranged around the machining fluid nozzle 14a so as to face the workpiece 25. And each hydraulic cylinder 2
Oil from a hydraulic pump 22 is supplied to pistons 20a, 20 in each hydraulic cylinder 20, 20 via 4-port 2-position switching valves 21, 21.
a moves up and down as the 4-port 2-position switching valves 21, 21 are switched. Therefore, piston 2
Piston rod 2 connected to 0a, 20a
0b and 20b also move in the same way as the pistons 20a and 20a move up and down.

Thus, the movement of the wire electrode 13 of the cross slide table (not shown) on which the stage 27 is placed in the tensioning direction and the vertical direction, the rotation of the board 3 by the motor 16, and the 4-port 2-position switching valve 21 ，
21 is controlled by a numerical control device 28 according to a preset program.

Therefore, no current is applied from the numerical controller 28 to the solenoid coils 21a, 21a of the 4-port 2-position switching valves 21, 21 until an arbitrary position or an arbitrary period of time elapses after the start of machining. The position switching valves 21, 21 are springs 21
b, 21b switches the hydraulic pressure from the hydraulic pump 22 in the direction of lifting the pistons 20a, 20a, so each hydraulic cylinder 20,
Permanent magnets 24, 24 are attracted to the lower end surfaces of 20, respectively. However, if a current is supplied from the numerical control device 28 to the selected solenoid coil 21a, 21a of the 4-port 2-position switching valves 21, 21 at any position or after any period of time, the 4-port 2-position switching valve The switching valves 21, 21 switch the hydraulic pressure from the hydraulic pump 22 when the magnetic force of the solenoid coils 21a, 21a is combined with the elastic force of the springs 21b, 21b. Therefore, the hydraulic pressure from the hydraulic pump 22 is applied to the hydraulic cylinders 20, 2.
Since the pistons 20a, 20a in 0 can be switched in the direction of pushing down, the hydraulic cylinders 20,
Permanent magnets 24, 24 attracted to the lower end surface of 20
are pushed downward by the piston rods 20b, 20b and separated from the lower end surfaces of the hydraulic cylinders 20, 20. Piston rod 20b, 20
Since b is made of non-magnetic material as mentioned above,
The permanent magnets detached from the lower end faces of the hydraulic cylinders 20, 20 by the piston rods 20b, 20b lose the object to be attracted and fall, and are attracted near the cut portion 25a of the workpiece 25. That is, it is attracted to a position where the cut piece of the workpiece 25 that has been cut by the wire electrode 13 and the main body of the workpiece 25 are bridged. Therefore, even after the desired processing is completed, it is possible to prevent the cutting portion 25a from bending or falling off.

Next, FIG. 4 will be explained.

In FIG. 4, the same numbers as in FIG. 1 indicate the same components, and 3a and 3a are mounting seats.

Therefore, in the device shown in Fig. 4, the permanent magnet 2
4 and 24 are attracted to mounting seats 3a and 3a provided on a substrate 3 made of magnetic material, and after being placed in any position or for any period of time, the numerical control device 28 controls the 4-port 2-position switching valve 21. , 21 selected solenoid coils 21a, 21a
When a current is supplied to the hydraulic pump 22, the hydraulic pressure from the hydraulic pump 22 is applied to the piston 2 in the hydraulic cylinder 20, 20.
The permanent magnets 24, 24 attracted to the mounting seats 3a, 3a are separated from the mounting seats by the pushing operation of the piston rods 20b, 20b, and fall. Then, the cut piece of the workpiece 25 that has been cut by the wire electrode 13 is adsorbed and placed at a position spanning and bridging both parts of the workpiece 25, thereby performing the desired processing. Even after the cutting is completed, it is possible to prevent the cutting portion 25a from bending or falling off due to its own weight.

Note that there are various configurations and combinations of the arm 1 and machining head 2 of this type of wire-cut electrical discharge machining apparatus, as well as various suspension guide systems for the wire electrode 13. A typical example is an arm extending from one column, or an arm spanning between a pair of columns standing on both sides, and a wire electrode 13 mounted on the front surface of the arm using a suspended guide roller, a capstan, or a pinch roller. A suspension guide path is formed for the processing head 2, or the processing head 2 is configured and arranged so as to be able to adjust and fix the processing head 2 vertically with respect to the arm 1 near the tip or center position. However, the present invention can be similarly applied to a wire cut electric discharge machining apparatus having such a configuration.

Further, the substrate 3 is the workpiece 2 of the processing head 2.
The hydraulic cylinders 20, 20 are not only provided to hold the hydraulic cylinders 20, 20 around the machining head 2 in the vicinity of the arm 1, but also project from the arm 1 toward the workpiece 25 in a cylindrical shape to cover the machining head. It is also possible to configure it to hold the substrate 3. In addition, a plurality of hydraulic cylinders 2 may be mounted on one board 3.
0 and 20, the arm 1 is extended from the processing head 2 to the surroundings, for example, in the same shape.
One hydraulic cylinder 20 at the tip of each arm 1
A substrate 3 may be provided on which the components are arranged.

As the permanent magnets 24, 24, in addition to conventional alnico magnets or ferrite magnets, so-called rare earth alloy magnets such as iron-chromium-cobalt alloy magnets and samarium-cobalt alloy magnets may be used. In particular, the above-mentioned rare earth alloy magnet has an extremely large maximum energy product, and by appropriately selecting the permeance series, for example, a magnet of 20 to 30 mmφ can have a large maximum energy product.
A weight of 10 kg or more can be attracted and held, and if the workpiece 25 and its cut portion are not particularly large, a few permanent magnets 24, 24 can be used to hold the workpiece 25 sufficiently and reliably.

In addition, in the above-described embodiment, a short cylindrical magnet piece was used as the permanent magnet 24, which has the possibility of magnetic attraction even on the side surfaces other than the NS extreme face, so that the mounting of the cylinder 20 and the board 3 was not easy. The seat 3a etc. are made of a magnetic material, and the magnet 24 is attracted and held therein.
The piston rod 20b is made of a non-magnetic material and is configured to peel off and fall from the cylinder 20 and the mounting seat 3a. Depending on the combination structure, it is possible to have a structure in which only a part or one end face is magnetically attracted, so in such a case, the cylinder 20, piston rod 20b, and mounting seat 3a are made of magnetic material, Or it may be any non-magnetic material. FIGS. 5A and 5B show a cross-sectional view A and a front view B of an embodiment of such a permanent magnet.
28 is, for example, a short cylindrical magnet of SmCo ₅ system, 29
is a cylindrical iron core with a concave shape on one side and a magnet 28 in the center of the concave portion, and 30 is a ring-shaped non-magnetic material made of synthetic resin or alloy that is interposed as necessary between the magnet 28 and the core. The iron core 29 is fixed by adhesive, mechanical fixing means, or the like.

In the magnet, the back surface 31 of the iron core 29 and the outer circumferential surface, particularly the back outer circumferential surface 32, have almost no magnetic adsorption ability as a permanent magnet. 3a may be a weak permanent magnet or an electromagnet, or, for example, as shown in the partial view in FIG. 6, an annular protrusion (or recess) may be provided at an appropriate position such as the outer peripheral surface portion 32 on the rear side of the permanent magnet 24 shown in FIG. 24a, and a ring-shaped rubber or spring 3b for hooking and holding the protrusion (or recess) 24a in the magnet fitting opening of the mounting base 3a, for example.
0b, the permanent magnet 24 is released from the magnetic attraction of the mounting seat or mechanically held by the spring 3b, etc., and is allowed to fall onto the workpiece 25.

Since the present invention is constructed as described above, according to the apparatus of the present invention, during wire cut electric discharge machining, as the electric discharge machining progresses, the cut portion is supported by the uncut portion by its own weight and bent downward. Therefore, it is possible to prevent the processing accuracy of the part being cut from deteriorating, and also to prevent the cut part from falling off automatically and efficiently without manual intervention.

Note that the present invention is not limited to the embodiments described above. That is, for example, in the device of the above embodiment, the hydraulic cylinder or the mounting seat part is made of a magnetic material, a permanent magnet is attracted to this, and the permanent magnet is moved downward by a non-magnetic piston rod that moves up and down with the piston. The piston rod was configured to be pressed to release and fall, but on the contrary, by making the piston rod a magnetic material, attaching a permanent magnet to the tip of the piston rod, and making the hydraulic cylinder or mounting seat part a non-magnetic material, The piston rod that has attracted the permanent magnet is pulled upwards, the permanent magnet is brought into contact with the hydraulic cylinder or the mounting seat, and the piston rod is further pulled up to remove the permanent magnet that is attracted to the tip of the piston rod from the piston rod. It may also be made to fall. In addition, the part that attracts the permanent magnet,
Alternatively, the parts of the hydraulic cylinder, mounting seat, and cylinder rod that the permanent magnet comes into contact with and removes do not need to be made entirely of magnetic or non-magnetic material, but the parts that the permanent magnet attracts or comes into contact with are made of magnetic material. Alternatively, a non-magnetic material may be used, and a ram may be used in place of the hydraulic cylinder, and the mounting position of the hydraulic cylinder on the board, the shape of the permanent magnet, etc. may be freely changed within the scope of the purpose of the present invention. However, the present invention encompasses all of them.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the wire-cut electric discharge machining apparatus according to the present invention, FIG. The figure is an explanatory view showing the state of the workpiece at the end of machining when the workpiece is machined using the wire cut electric discharge machining apparatus according to the present invention, and FIG. 4 is an explanatory view showing another embodiment. , FIGS. 5A and 5B are a sectional view and a front view showing an example of a modified configuration of the permanent magnet used, and FIG. 6 is an explanatory diagram of the configuration of a part when implementing the present invention using the permanent magnet shown in FIG. 5. . 1...Support arm, 2...Processing head, 3...
Board, 3a... Mounting seat, 4, 5... Guide roller, 6... Current roller, 7, 8... Capstan, 9, 10... Pinch roller, 11, 12...
Electrode guide, 13...Wire electrode, 14...Holding plate, 14a...Working liquid nozzle, 15a, 19a...
...Mounting bolt, 16...Motor, 17, 18
...Gear, 20...Hydraulic cylinder, 20a...Piston, 20b...Piston rod, 21...4
Port 2 position switching valve, 21a...Solenoid coil, 21b...Spring, 22...Hydraulic pump, 23...Oil tank, 24...Permanent magnet, 25
... Workpiece, 25a ... Cutting section, 26 ... Clamp, 27 ... Stage, 28 ... Numerical control device.

Claims (1)

[Scope of Claims] 1. A mounting seat on which a plurality of permanent magnets can be mounted on a surface facing a workpiece, the end surface of which a piston rod of a cylinder for removing permanent magnets, which will be described later, advances, may also serve as the mounting seat. A board having a mounting seat and rotatably attached to a processing head; a permanent magnet detachably attached to each mounting seat of the board; and a permanent magnet removal cylinder provided corresponding to the mounting seat. , comprising a fluid pressure supply device that operates the permanent magnet detachment cylinder, a rotation device that can rotate the substrate, and a control device that controls the operation of the rotation device and the permanent magnet detachment cylinder, Each mounting seat portion of the board is made of a magnetic material, and at least the tip of the piston rod of the permanent magnet removal cylinder is made of a non-magnetic material. The present invention is equipped with a device for preventing cut pieces from falling off, which is configured so that the permanent magnet, which has been retracted and attracted to the mounting seat when the piston rod is retracted, is detached from and falls from the mounting seat by advancing the piston rod. A wire cut electrical discharge machining device featuring: 2. The wire cut electric discharge machining apparatus according to claim 1, wherein the permanent magnet detachment cylinder is a hydraulic cylinder. 3. The wire cut electric discharge machining apparatus according to claim 1, wherein the permanent magnet detachment cylinder is a hydraulic ram. 4 A mounting seat capable of attaching a plurality of permanent magnets to the surface facing the workpiece, which has the mounting seat which may also be used as the end face portion on the side where the piston rod of the cylinder for permanent magnet removal described later advances, and is capable of processing. a board rotatably attached to the head; a permanent magnet detachably attached to each mounting seat of the board; a cylinder for removing the permanent magnet provided corresponding to the mounting seat; a cylinder for removing the permanent magnet. a fluid pressure supply device that operates a cylinder; a rotation device that can rotate the substrate; and a control device that controls the operation of the rotation device and the permanent magnet detachment cylinder; is made of a non-magnetic material, and at least the tip of the piston rod of the permanent magnet detachment cylinder is made of a magnetic material, and when the piston is retracted, the tip is retracted above the lower end surface of the mounting seat, and the piston rod is made of a magnetic material. When the permanent magnet is attracted to the tip of the piston rod,
A wire-cut electric discharge machining apparatus comprising a device for preventing cut pieces from falling off and falling off from the tip of the piston rod by retracting the piston rod. 5. The wire cut electric discharge machining apparatus according to claim 4, wherein the permanent magnet detachment cylinder is a hydraulic cylinder. 6. The wire cut electric discharge machining apparatus according to claim 4, wherein the permanent magnet detachment cylinder is a hydraulic ram. 7. A substrate that has a mounting seat on the surface facing the workpiece to which a plurality of permanent magnets can be attached and is rotatably attached to the processing head, and a permanent magnet that is detachably attached to each mounting seat of the substrate; a permanent magnet detachment cylinder provided corresponding to the mounting seat; a fluid pressure supply device that operates the permanent magnet detachment cylinder; a rotation device capable of rotating the substrate; the rotation device and the above. and a control device for controlling the operation of the permanent magnet detachment cylinder, wherein the permanent magnet has a configuration in which a cylindrical permanent magnet is fixed to the center of a recess of an annular iron core having a concave shape on one side, and the mounting seat. has a holder that holds the part of the permanent magnet that does not have magnetic attraction ability and fixes it to the mounting seat, and the permanent magnet is held by the holder of the mounting seat when the piston rod of the permanent magnet removal cylinder retracts. A wire cut electrical discharge machining apparatus characterized in that the magnet is equipped with a cut piece fall-off prevention device configured to allow the magnet to separate from and fall from the mounting seat against the holding force of the holder by advancing the piston rod. . 8. The wire cut electric discharge machining apparatus according to claim 7, wherein the permanent magnet detachment cylinder is a hydraulic cylinder. 9. The wire cut electric discharge machining apparatus according to claim 7, wherein the permanent magnet detachment cylinder is a hydraulic ram.