JPH0455807B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is characterized in that a pair of machining fluid injection nozzles through which a wire electrode is inserted are opposed to each other, and a workpiece that is interposed between both nozzles and the wire electrode are The wire cut electric discharge machining method applies intermittent voltage pulses or discharge pulses and spouts pressurized machining fluid toward the machined part from both nozzles, and is particularly suitable for high-speed cutting. It relates to things that have preventive measures.

(Prior art) In wire cut electric discharge machining, in order to perform high-speed machining, the machining fluid pressure or flow rate or flow rate in the machining part is increased to prevent the generation of bubbles in the machining part and the entrainment of air bubbles from the outside. At the same time, it is necessary to increase the flow of liquid in the machined part and keep the temperature low in order to prevent the occurrence of atmospheric discharge, remove machined debris at high speed, and prevent wire electrode breakage accidents.

However, if the supply amount and pressure of machining fluid are increased and the fluid is injected from the nozzle to the machining part, the amount that leaks from the nozzle tip to the outside without passing through the machining part and the amount that scatters to the surroundings increases. The machining fluid jetted and supplied from one nozzle could not have sufficient influence on the flow of machining fluid flowing through the machining section when it was jetted out from the other nozzle, and the amount of machining fluid supplied to the machining section was not as high as expected. There were cases where the distribution flow did not increase.

(Problems to be Solved by the Invention) In view of the above points, the present invention has the following features for high-speed processing:
It is possible to reduce the flow rate of machining fluid that leaks to the outside without passing through the machining part or flows down unnecessarily, and as a result, increases the flow rate and pressure of machining fluid to the machining part. It is an object of the present invention to provide a wire cut electric discharge machining method that can change and control the leakage flow rate of machining fluid or the state of the flow of machining fluid in a machining section so that machining can always be performed under predetermined machining fluid conditions.

(Means for Solving the Problems) The method of the present invention provides a method of supplying a powdered magnet to the surface of the workpiece made of a magnetic material from the opposing nozzles or the vicinity of the nozzle. A powder magnet is attracted to the nozzle tip in an almost coaxial ring shape to form a kind of enclosure, which prevents machining fluid from leaking to areas other than the machining area along the workpiece surface where the nozzle tip contacts. It is characterized in that the flow state of the machining fluid in the part can be changed as desired.

(Function) In the present invention, the leakage of machining liquid to parts other than the machining part is prevented or the easy scattering of the machining fluid is prevented, so the flow rate, fluid pressure, or flow velocity in the machining part can be increased. , powder magnet supply amount,
For example, by controlling the timing, for example, by supplying powdered magnet only to the machining part of the corner part, it is possible to reduce the machining feed rate or machining energy at the same level as the straight part or conventional corner part. This enables faster and more stable machining than would otherwise be possible, and reduces problems such as sag at corners and wire electrode breakage accidents at corners.

(Example) An example of the present invention will be described below with reference to the drawings.
The drawing is a diagram showing an example of the configuration around a machining fluid injection nozzle to which the present invention is applied, in which 1 is a wire electrode, 6A,
6B is the guide roller 7A, 7B of the wire electrode 1.
The upper arm and the lower arm are attached to a column or the like of the device main body (not shown). 8A, 8B are manual handles or motors 9
Arm 6 can be adjusted up and down by A and 9B.
A and 6B are attached to the support members, and 10 is a current-carrying pin, which is attached to the support member 8A and contacts the wire electrode 1 which is pressed and displaced by the abrasion-resistant and insulating press pin 10'. This constitutes an upper current supply device that applies voltage to the electrodes. Reference numeral 11 denotes a current-carrying roller serving as a lower current-carrying device that also serves as a lower guide roller; 12 and 13 are mounted to the supporting members 8A and 8B, respectively, in a direction perpendicular to the axial direction of the wire electrode 1 so as to be able to minutely adjust the position thereof, or to be fixed thereto; The nozzle bodies 12 and 13 have openings 14, 15 and 16, 17 at their upper and lower end surfaces, respectively.
is formed.

Inside the nozzle bodies 12 and 13, guide holders 20 and 21 of the upper and lower positioning guides 18 and 19 are coaxially fixed, respectively, and the lower end opening 15 of the upper nozzle body 12 and the lower nozzle body Each nozzle 2 is provided in the upper end opening 17 of 13.
2 and 23 are coaxially fixed so as to face each other (nozzle 22), or are fitted so as to be movable in the axial direction (nozzle 23). The guide holders 20 and 21 are hollow cylindrical bodies having holes 20a and 21a through which the processing liquid in the nozzle bodies 12 and 13 flows. Further, the nozzles 22 and 23 are hollow cylindrical bodies having a desired axial length, inner diameter, and axial diameter restriction, and the lower nozzle 23 is prevented from falling off from the nozzle body 13 by a flange 23a.
In addition, if necessary, a push spring may be provided to counteract the machining fluid pressure.

Pressurized machining fluid supply hoses 25 and 26 are attached to the nozzle bodies 12 and 13, respectively, from which the machining fluid is supplied into each nozzle body 12 and 13 at a predetermined pressure and flow rate, thereby controlling the internal positioning. The guides 18 and 19 are cooled, and the jets are ejected from the upper and lower nozzles 22 and 23 to the processing section 27 of the workpiece 24 coaxially along the wire electrode from above and below, respectively, and from the opening at the upper end of each nozzle body 12. 14 and the lower end of the nozzle body 13 to supply machining fluid also between the current-carrying pin 10 and the current-carrying roller 11 and the wire electrode 1, thereby cooling the wire electrode 1, the current-carrying pin 10, and the current-carrying roller 11. ing. Reference numeral 30 indicates a machining groove, and 39 and 40 indicate flows of machining fluid ejected from the upper and lower nozzles 22 and 23, respectively.

The workpiece 24 is fixed to a processing table 31, and the processing table 31 is connected to an X-axis motor 32 and a Y-axis motor 32.
The shaft motor 33 allows the wire electrode 1 to be freely moved along a predetermined contour on a plane perpendicular to the axis under the control of a numerical controller. Further, the wire electrode 1 is pulled out via a brake roller or the like from a storage reel provided in a column or the like of the apparatus main body (not shown), extends downward from the guide roller 7A section, and is connected to the energizing pin 10, the upper nozzle main body 12, and the guide 18. , the nozzle 22, the processing section 27 of the workpiece 24, the lower nozzle 23, the guide 19, the lower nozzle main body 13, and the column via the energizing roller 11 and guide roller 7B of the lower arm 6B, via a winding roller (not shown). It is adapted to be wound up or collected on a take-up reel of the main body or a collection container. Then, intermittent voltage pulses are applied between the workpiece 24 and the wire electrode 1 to perform electrical discharge machining.

However, in this embodiment, the upper and lower nozzles 2
2, 23 (or the nozzle bodies 12, 13), the powder magnet supplying auxiliary nozzles 43, 45 are attached to surround the nozzles 22, 23, and each auxiliary nozzle 4
3 and 45, respectively, a powder magnet supply hose 44,
Install 46.

FIG. 2 is a diagram showing a supply device for machining fluid and powdered magnets to the nozzles 22, 23 and auxiliary nozzles 43, 45, and numeral 41 indicates a powdery magnet mixed into the machining fluid such as water to improve fluidity. A hopper containing the fluid 42 held therein, 47 a valve device provided at its lower end, 48
is actuated by a motor 48a to supply the fluid 4
2 to the auxiliary nozzles 43, 45 through a pipe 49.
50 is a processing liquid receiver for storing processing liquid, and 51 is a solid content separation device such as a cyclone that separates the processing liquid into liquid and solids such as processing waste and powdered magnets. The machining fluid flows up the inside of the pipe wall of the cyclone 51 and is separated, and flows into the machining fluid tank 52 and stored therein, while the separated machining waste descends from the inside wall of the cyclone and flows down from the bottom outlet. It flows down to the storage tank 53 and is stored. A pump 54 is actuated by a motor 54a to jet the machining liquid in the tank 52 from the nozzles 22 and 23 through a pipe 55.

Reference numeral 56 denotes a processing power source, which has a function of selecting and switching electrical conditions (voltage pulse width, pause width, no-load voltage, short-circuit current value, etc.) of the output voltage pulse and the discharge pulse caused by the voltage pulse. 57 is the processing power source 56 and the motors 32, 33, 48a, 54
This is an NC device that controls the drive motor 58a of the winding reel 58 of the wire electrode 1 and the winding reel 58 of the wire electrode 1 based on processing information stored in an auxiliary storage device 59.

When processing using this device, the motor 58a is operated by the NC device 57 to wind the wire electrode 1 onto the take-up reel 58.
At the same time as moving the wire electrode 1 in its axial direction, the X-axis motor 32 and the Y-axis motor 33 are operated based on the machining position information stored in the auxiliary storage device 59 to move the workpiece 24 relative to the wire electrode 1. The wire electrode 1 and the workpiece 24 are moved relative to each other, and voltage pulses are intermittently applied from the processing power source 56.
Either the voltage pulse or a constant DC voltage is applied to the built-in capacitor to charge it, and the operation of discharging between the wire electrode 1 and the workpiece 24 is repeated, and then the hopper 4
1 valve device 47 is opened to a suitable opening degree, and the motors 48a, 54a are operated to open the nozzles 22, 23.
The machining liquid is ejected from the auxiliary nozzles 43 and 45 toward the machining section 27, and the fluid containing the powdered magnet flows out from the auxiliary nozzles 43 and 45.

In this way, if the fluid 42 containing the powdered magnet flows out from around the nozzles 22 and 23, as shown around the upper nozzle 22 in FIG.
This powder magnet 60 is attached to the wire electrode 1 on the surface of the workpiece 24 only when the workpiece 24 is a magnetic material.
These are attached to the nozzle 2 in an almost coaxial and equicyclic shape.
2 to suppress the leakage flow of the machining fluid shown by the imaginary line 61,
In addition to blocking and even preventing the machining fluid flow 40 from the lower nozzle 23 from flowing out from the top through the machining groove 30, the machining section 27
This increases the flow rate, pressure, or density of the machining fluid, which eliminates the generation of bubbles, ensures that machining debris is washed away, and enables stable, high-speed machining.

By the way, as shown by the imaginary line 62 in FIG.
At the corners of the machining groove 30, machining instability occurs due to dripping and cracking of the jet machining fluid, but this droop eliminates machining instability at the corner portions, increases the machining speed compared to the past, and guides 18, 19. By improving the straightness of the wire electrode 1, the wire electrode 1 becomes smaller as shown by the solid line 63, and the number of breakage accidents of the wire electrode 1 is reduced. This can be seen in the 5th longitudinal cross-sectional view.
It will look like the figure. As shown in FIG. 5, when the machining speed is slow, the gap (bulge) between the wire electrode 1 and the machining surface is large as shown by the imaginary line 62, and when the machining speed is high, the gap (bulge) between the wire electrode 1 and the machining surface is large as shown by the solid line 63. The gap becomes smaller.

Therefore, as shown in FIG. 6, in order to perform stable high-speed machining without causing jet liquid cracking or the like at the corner portion 64, the valve device 47 is installed just before or a little before the machining contour path of the corner portion begins to curve. If the fluid 42 is temporarily opened and the motor 48a is operated to supply the fluid 42 from the auxiliary nozzles 43 and 45 to the workpiece 24 to prevent leakage of the machining fluid, sag at the corner and unstable machining can be avoided. Alternatively, wire electrode breakage accidents can be reduced.

7 and 8 show another embodiment of the present invention, in which the hose 4 is provided outside the nozzle body 12.
4 is attached so that an annular flow path 66 is formed between the cylindrical body 65 and the nozzle body 12. Outlet 6 only on one side through
An external gear 70 having a rotary body 69 having a diameter of 9a attached to the outer periphery of the rotary body 69 is meshed with a gear 72 rotated by a motor 71 attached to the cylindrical body 65, and the motor 71 is set to the machining position information. By activating the process accordingly, the machining fluid flow 40 through the machining groove 30 from the counterpart nozzle 23 is blocked, and the machining fluid flows into the wire electrode 1 by covering the machining groove 30 immediately after machining. By arranging the flow to flow from the front in the direction of machining progress, leakage of machining fluid can be effectively prevented with a small number of powdered magnets.

In addition, in the above embodiment, two nozzles 2
2 and 23 have been shown in the example in which they face each other in the vertical direction, but they may also face each other in the horizontal direction. Further, a means for discharging the powdered magnet may be provided in either the nozzles 22, 23 or the nozzle bodies 12, 13, and the powdered magnet is supplied to the auxiliary nozzle 43 which surrounds the nozzles 22, 23 in a substantially coaxial annular shape. , 45 or the rotating body 69 having the outlet 69a, etc., but may be configured to mix with the machining liquid and eject from the nozzles 22, 23. Therefore, in that case, the auxiliary nozzle 4
3, 45 and the rotating body 69 are no longer necessary, but the powdered magnet ejected from the nozzles 22, 23 together with the machining fluid is attracted between the openings at the tips of the nozzles 22, 23 and the surface of the workpiece 24. The nozzles 22, 23 have a thick wall around their tip openings to facilitate retention, or the nozzles 22, 23 have a thick wall.
A ring-shaped body made of a ferromagnetic material such as iron can be embedded in the surface facing the workpiece 24 around the tip opening so that the powder magnet can also be attracted to the ring-shaped body, and the ring-shaped body can be permanently attached. If it is a magnet, the powder magnet is a ferromagnetic powder that is not a permanent magnet and is attracted not to the surface of the workpiece 24 but to the surface facing the workpiece 24 around the openings at the tips of the nozzles 22 and 23. In this way, most of the ferromagnetic powder is absorbed by the nozzle 22, unlike the case where the powder magnet is blocked by the machining contour line on the surface of the workpiece 24 and is attracted.
Since they will be traveling together with 23, their supplies will be small and will only need to be done once in a while. Note that this annular magnet may be provided on the surface facing the workpiece around the tip opening of the auxiliary nozzles 43, 45 or the rotating body 69. According to this method, the workpiece 24 is not made of a magnetic material. In this case, it is also possible to perform processing that enjoys substantially the same objectives, effects, and effects as those of the present invention.

(Effects of the Invention) According to the present invention, it is possible to increase the flow rate, flow velocity, or liquid pressure of the machining fluid supplied to the machining section, thereby reducing the generation of bubbles in the machining section and the entrainment of air bubbles from the outside. In addition to preventing the occurrence of aerial discharge, it is possible to generate a machining fluid flow suitable for high-speed machining. In addition, by controlling the supply of powdered magnets, it is possible to control the amount of leakage according to the shape of the processed part, allowing for more flexible processing compared to the case where a fixed leakage prevention member is installed. A liquid flow can be generated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration around a nozzle according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a system for supplying machining liquid and powdered magnet of the present invention,
FIG. 3 is a cross-sectional view explaining the action of the present invention, FIG. FIG. 7 is a sectional view showing another embodiment of the present invention, and FIG. 8 is a sectional view taken along line EE in FIG. 7.

Claims (1)

[Scope of Claims] 1. While a wire electrode is updated and moved in the axial direction between a pair of positioning guides arranged at intervals, the workpiece is relatively moved in a direction substantially perpendicular to the axial direction of the wire electrode. The wire electrode and the workpiece are moved and the machining fluid is sprayed and supplied along the wire electrode from machining fluid spray nozzles arranged so as to face each other on both sides of the workpiece to the machining section where the wire electrodes and the workpiece face each other. In wire cut electrical discharge machining, in which intermittent voltage pulses or voltage pulses are applied in between, and machining is performed by the generated discharge, a powdered magnet is applied from the opposing nozzles or the vicinity of the nozzle to the workpiece made of a magnetic material. A wire cut electric discharge machining method characterized in that a powdered magnet is attracted to the workpiece in a substantially coaxial annular shape around the nozzle tip by supplying it to the surface of the workpiece, thereby preventing leakage of machining fluid to areas other than the machining area. . 2. The wire cut electric discharge machining method according to claim 1, wherein the powdered magnet is supplied to the surface of the workpiece to a portion of the workpiece immediately after being machined. 3. The wire cut electric discharge machining method according to claim 1 or 2, characterized in that the powdered magnet is supplied to the surface of the workpiece only during corner machining.