JPH0532171B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a wire cutting device that performs electrical discharge machining using a thin wire electrode, particularly in a machining fluid supply nozzle portion.

[Prior art and problems]

In ear cut electric discharge machining, the hydraulic pressure, flow rate, and flow rate of the machining fluid in the machining part are increased to prevent the generation of bubbles in the machining part, the occurrence of air discharge due to the entrainment of air from the outside, and the production of machining debris. It is required to promote high-speed removal of wire, enable stable high-speed machining, and increase the cooling effect of the wire electrode to reduce wire breakage and perform efficient machining. In addition, since the thin wire is energized and guided with strong tension in the part other than the part facing the workpiece, there is a risk of stretching or deforming, and this also needs to be cooled by supplying machining fluid. There is a need.

Conventional machining fluid supply nozzles have been proposed in which a jet nozzle is provided coaxially with the wire electrode, thereby cooling the discharge part of the wire electrode and parts other than the discharge generation part, but each has insufficient effect. was not obtained, and the desired high-speed processing was impossible.

In other words, today there are strict requirements for both machining speed and machining accuracy, and there is a growing demand for such mechanical devices that can operate stably for long periods of time and that require no maintenance or servicing. .

[Means for solving problems]

The present invention has been proposed to improve this point, and the positioning is performed by contacting the wire electrodes along each wire electrode on both the front and back sides of the workpiece and in a direction away from the surface of the workpiece. guide and
a current-carrying contact that contacts the wire electrode and conducts the voltage pulse, and a machining fluid oriented substantially perpendicularly to the surface of the workpiece and in contact with the current-carrying contact and the guide along the electrode axis. A low-pressure, high-flow low-pressure nozzle that discharges as a cooling liquid is sequentially installed, and the wire electrode workpiece, which is the processing part, is placed at a predetermined distance from both surfaces of the workpiece around the wire electrode axis. It is characterized by being provided with a plurality of high-pressure machining liquid spray nozzles oriented toward the front and back entrances and exits.

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

1 is a wire electrode with a wire diameter of about 0.05 to 0.3 mmφ.
Cu, Bs, other alloy wires, coated wires, etc. are used.
It is supplied from a reel (not shown) and travels between the guides 2 and 3 in the direction of the arrow (or in the opposite direction) at a required speed. Although not shown, a brake is provided on the supply side and a tension roller is provided on the opposite side to control the required tension and speed. 4 is guide 2, 3
This is a workpiece to be machined facing the wire electrode 1 between the wire electrodes 1 and 1, and is normally attached to a position-controlled machining table (not shown), and a machining feed of the required machining shape is given between the wire electrode 1 and the wire electrode 1 by NC control. . In the figure, it is fed in the direction of the arrow from right to left, and the hatched unprocessed portion is processed. A pulse current is applied between the wire electrode 1 and the workpiece 4 from a processing power source (not shown), and the wire electrode 1 is energized by current-carrying pins 5 and 6. Reference numerals 9 and 10 are pressing pins for making good electrical contact. Reference numerals 7 and 8 indicate machining fluid supply nozzles provided on both sides of the workpiece 4, which are a combination of a nozzle 71 that supplies each low-pressure machining fluid, nozzles 72 and 73 that supplies high-pressure machining fluid, and a low-pressure machining fluid. It consists of a combination of a nozzle 81 for supplying water and nozzles 82 and 83 for supplying high-pressure machining fluid. Low pressure nozzles 71 and 8 as shown
1 is provided so as to cool the front portion of the wire electrode 1 facing the workpiece 4 and the portion of the wire electrode that has passed through the workpiece 4. Especially the current-carrying pin 5,
6. A cooling liquid is provided to flow through the guides 2 and 3, and a large amount of processing liquid is required to be supplied there, and the required amount is supplied by a pump. or,
The high-pressure nozzles 72, 73 and 82, 83 inject and supply machining fluid toward the discharge generating portion of the wire electrode facing the workpiece 4. As shown in the figure, the axis of the wire electrode 1 is slightly inclined (approximately 5 degrees or less) to direct the jet liquid so that it flows approximately along the wire electrode.

[Effect]

In the above, the machining fluid is supplied to the high-pressure nozzle by a pump, etc., but the machining fluid that is jetted and supplied flows directly to the machining part and has effects such as acting as a discharge medium, cooling action, and removing machining debris. In order to supply and distribute machining liquid with sufficient amount and flow rate to counter the discharge pressure, the ejection pressure varies depending on the thickness of the workpiece 4, but it is required to be at least 3 to 5 kg/cm ² or more. , a pressure of approximately 15 to 50 kg/cm ² is used, especially when processing thick objects of 200 mm or more.
Approximately Kg/ ^cm2 is required. Also, the supply amount is approximately 50
~500c.c./min is required. On the other hand, low pressure nozzle 7
1 and 81 are in contact with the current-carrying pins 5 and 6 and the guides 2 and 3, etc., in order to mainly cool the parts other than the discharge part of the wire electrode 1 which is discharged, and the jet pressure is about 1 to 81.
Even at a low pressure of about 5 kg/cm ² , it is necessary to flow a large amount of liquid at 1 to 5 min., and the supply pump, adjustment valve, etc. must be set. The same machining fluid may be used for the high-pressure nozzle and the low-pressure nozzle, but since it flows into the machining part of the workpiece 4 through a narrow gap between the wire electrode 1 and the wire electrode 1, the fluid supplied from the low-pressure nozzles 71 and 81 is Since almost no liquid enters the machining fluid, it is not necessary to use the same machining fluid for the high-pressure nozzle as the supply fluid for the low-pressure nozzle.For example, the machining fluid supplied from the high-pressure nozzle to the machining gap of the machining part is used for electrical discharge machining. Pure water that has been treated to have a specific resistance of about 10 ⁵ to 5 x 10 ⁴ Ωcm is used to stabilize the process, and water with a specific resistance of about 10 ⁴ to 5 x 10 ³ Ωcm is supplied from the low-pressure nozzle because it is mainly used for cooling. can be used.

In addition, high pressure jet nozzles 72, 73 and 82, 83
Since it is necessary to flow a large amount of machining fluid into the machining area without mixing air bubbles, etc., the tip of each nozzle is oriented at the required angle of inclination, and the wire is coaxially distributed around the entire periphery approximately at the center of the wire electrode 1. Adjustments are made so that the fluid flows in a wrapping manner to ensure stable machining through sufficient flow of the machining fluid.
However, the upper nozzle 8 may have one or two, and the lower nozzle 7 may have two or more on the circumference, or the nozzles may be controlled to rotate around the circumference. good. Further, it is possible to control the jet pressure and the jet amount of the upper and lower nozzles so that a uniform jet is generated by making a difference. Also, low pressure nozzles 71, 8
1 may be provided so as to surround the current-carrying pins 5 and 6 and further the guides 2 and 3, or may be provided so as to be poured from the side of the wire electrode 1, and furthermore, a plurality of electrodes may be provided facing each other around the wire electrode 1. can.

〔Effect of the invention〕

As explained above, the present invention provides three guides for positioning the wire electrodes by contacting the wire electrodes along the wire electrodes on both the front and back sides of the workpiece and in a direction away from the workpiece surface; and a current-carrying contact that energizes the voltage pulse, and a machining fluid as a cooling liquid oriented substantially perpendicularly to the surface of the workpiece and in contact with the current-carrying contact and the guide along the electrode axis. A low-pressure nozzle with a low pressure and a high flow rate is sequentially installed, and furthermore, entrances and exits on the front and back of the workpiece of the wire electrode, which are the processing parts, are provided at positions separated by a predetermined length from both surfaces of the workpiece around the wire electrode axis. Since the configuration includes a plurality of oriented high-pressure machining liquid spray nozzles, the means for applying voltage pulses to the guide and wire electrode for achieving machining accuracy can be provided closer to the front and back surfaces of the workpiece. In addition, each nozzle can share the function of supplying machining fluid.The low-pressure nozzle is provided mainly for cooling the parts other than the discharge part of the wire electrode that are in contact with the current-carrying pins, guides, etc., and the high-pressure nozzle is used mainly for cooling the parts other than the discharge part of the wire electrode. It can be installed to supply the discharge part of the electrode facing the workpiece, and by sharing the supply of machining fluid, it is possible to optimize the fluid pressure, flow rate, direction control, etc. to each part, and the sufficient cooling effect makes it possible to conduct electricity. And in the guide part, the machining speed and machining accuracy are improved by stable energized guide without stretching, deforming or breaking even when guided with large current and strong tension, and the machining speed and machining accuracy are improved. By supplying machining fluid at the optimum flow rate to the inside of the plate, even when the plate thickness is thick, it can flow sufficiently to the inside by controlling the jet pressure, direction, etc., and as a discharge medium, machining debris, etc.
It functions satisfactorily as a gas expelling body, thereby making it possible to perform stable high-speed electrical discharge machining.
Further, the supply processing liquid can be divided into a high pressure nozzle and a low pressure nozzle. In other words, the machining fluid supplied from the low-pressure nozzle is directed toward the current-carrying parts other than the discharge part and is at low pressure, so it cannot easily enter the narrow machining gap, and the machining fluid is mainly supplied to the machining part using the high-pressure nozzle. Because machining fluid is supplied from
This high-pressure nozzle is supplied with machining fluid with strict resistivity control using ion-exchange resin to perform electrical discharge machining with improved performance, while the low-pressure nozzle allows for less stringent resistivity control and widens its range. It is possible to use a processing liquid that has been processed using the ion exchange resin, and therefore, the amount of treatment with the ion exchange resin can be reduced, which has the effect of saving the amount of ion exchange resin. In addition, the high-pressure nozzles can be oriented in any direction as long as the machining fluid is supplied well to the machining part, and any number of high-pressure nozzles can be provided facing each other, or the jet can be jetted while moving around the wire electrode. Since the amount of machining fluid supplied by this high-pressure nozzle is relatively small, there is little scattering to the surroundings even with high-pressure jetting, reducing the amount of machining fluid used and improving workability. It also has the effect of

[Brief explanation of drawings]

The drawing is a configuration diagram of an embodiment of the present invention. 1... Wire electrode, 2, 3... Guide, 4...
Workpiece, 5, 6... Current-carrying pin, 7, 8... Machining liquid nozzle, 71, 81... Low pressure nozzle, 72, 7
3, 82, 83...High pressure nozzle.

Claims (1)

[Claims] 1. A workpiece is placed facing a wire electrode that moves between a pair of positioning guides arranged at intervals by updating feed in the axial direction from a direction substantially perpendicular to the electrode axis to form an electrical discharge machining gap, and the machining A pulse discharge is generated by applying intermittent voltage pulses between the workpiece and the wire electrode with machining fluid flowing therebetween, and a pulse discharge is generated between the wire electrode and the workpiece in the perpendicular direction. In wire cut electric discharge machining that provides relative machining feed on a plane, the wire electrodes are contacted with the wire electrodes on both the front and back sides of the workpiece, and in the direction away from the workpiece surface. a guide for positioning; a current-carrying contact for contacting the wire electrode and energizing the voltage pulse; Low-pressure, large-flow low-pressure nozzles that discharge machining fluid as a cooling fluid are sequentially provided so as to be in contact with each other, and the machining section is further spaced a predetermined distance from both surfaces of the workpiece around the wire electrode axis. A wire-cut electric discharge machining device comprising a plurality of high-pressure machining fluid spray nozzles oriented toward the front and back entrances and exits of a workpiece of a wire electrode.