JPS6236587Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention is an energizing device for wire cut electrical discharge machining, specifically a energizing device that generates heat, a wire electrode in the relevant part, and a method for cooling the heat generated between the wire electrode and the energizing device. The present invention relates to an energizing device for wire cut electric discharge machining configured to be able to perform the following steps.

[Background technology]

A wire cut electrical discharge machining device moves a wire electrode between a pair of positioning guides while maintaining a predetermined tension while reeling the wire electrode from one reel and winding it onto the other reel. A machining gap is formed by facing the workpiece from a direction approximately perpendicular to the axis of the wire electrode moving between the two.
A machining fluid such as water or oil is supplied to this gap, and a machining voltage pulse is supplied to generate a pulse discharge, and while this discharge is repeated, the workpiece and the wire electrode are relatively machined in the opposing direction. Cutting is performed by feeding and moving.

For example, a wire cut electric discharge machining apparatus shown in FIG. 1 will be explained. This wire-cut electrical discharge machining device is unwound from a reel provided in a column or the like of the device main body (not shown) via a brake roller, etc., and extends downward via a guide roller 11 of an arm 1.
Provided below to face arm 1 (not shown)
Intermittent voltage pulses are applied between the guide roller of the arm, the take-up roller, the take-up reel of the main body such as the column, or the part between the guide rollers of the wire electrode 2 that reaches the collection container, and the workpiece 3. This machine performs electrical discharge machining. Arm 1 placed above
The upper part of a support member 13 having an L-shaped cross section is attached to the support member 13 so as to be substantially perpendicular to the arm 1 and to be vertically movable and positionable by a manual handle or a motor 12. On the lower front surface of the support member 13,
A wear-resistant, usually cylindrical, current-carrying pin 4 made of cemented carbide or the like is attached to contact the wire electrode 2 and apply a voltage pulse, and comes into contact with the wire electrode 2 in a substantially straight line between the guide rollers 11. ing. 4
Reference numeral 1 denotes a wear-resistant, usually insulating pressing pin for pressing the wire electrode 2 against the current-carrying pin 4, and is provided in parallel with the member 13 together with the pin 4.
An appropriate portion such as the upper end of a hollow cylindrical nozzle main body 5 is fixed to the lower end of the nozzle 3 so as to be able to minutely adjust the position as required. Openings 51 and 52 are formed in the upper and lower end surfaces of the nozzle body 5, and these openings 51 and 52 are formed approximately at the center axis of the nozzle body 5, so that the wire electrode 2 between the guide rollers 11 is coaxial. They are arranged in such a positional relationship that they are inserted into each other. Further, a guide holder 6 of an upper positioning guide 61 is coaxially inserted into the nozzle body 5, and a nozzle 7 is coaxially inserted into the lower end face opening 52 so as to be movable in the axial direction. has been done. The guide holder 6 is a hollow cylinder having a hole 6a, and a dice-shaped positioning guide 61 is attached to the lower end of the guide holder 6. The guide 61 is used to position the wire electrode 2 above the workpiece 3. There is. The guide holder 6 is attached to the nozzle body 5
It is fixed in such a way that its position can be adjusted minutely as necessary. Further, the nozzle 7 is arranged at the lower part of the nozzle body 5, and is fitted into the opening 52 at the lower end of the nozzle body 5 so as to be able to move up and down according to the supply pressure and flow rate of the machining fluid, the distance from the workpiece 3, etc. There is. The nozzle 7 is a hollow cylindrical body having a desired axial length, inner diameter, and axial inner diameter restriction, and the outer diameter of the end 71 of the flange portion located inside the nozzle body 5 is equal to the opening at the lower end of the nozzle body 5. The end portion 71 is formed to have approximately the same inner diameter as the inner diameter of the opening portion 52 , and the end portion 71 fits and contacts the inner wall of the opening portion 52 to prevent the nozzle 7 from falling off from the nozzle body 5 . Note that a spring 72 is provided as necessary for the upper nozzle 7, and is provided in response to the lower nozzle 7 being pushed up by the liquid flow against gravity. A pressurized machining fluid supply hose 53 is attached to an appropriate position on the upper side of the nozzle body 5, from which machining fluid is supplied into the nozzle body 5, cools the positioning guide 61 inside, and cools the positioning guide 61 at the bottom. Workpiece 3 from nozzle 7
The upper opening 51
The machining fluid is spouted further upwards to supply the machining liquid also between the current-carrying pin 4 and the wire electrode 2, thereby cooling the wire electrode 2 and the current-carrying pin 4. Further, the workpiece 3 is fixed to a processing table 31, and the processing table 31 is moved along a predetermined contour shape etc. on a plane perpendicular to the two axes of the wire electrode by motors 32 and 33 under the control of a numerical controller. It is now possible to move around freely. Note that many of the configurations and members described above are provided not only above the workpiece 3 but also below the workpiece 3. Other than the fact that each member is arranged so that the upper and lower parts are approximately symmetrical, the explanation is the same as that described above, so the explanation will be omitted. In order to make contact with the wire electrode 2 which has already been used, an energized roller having a diameter sufficiently larger than that of the pin 4 and brushed by a rotatable power supply is usually used.

The wire cut electric discharge machining apparatus is configured in this way, and a voltage pulse is applied between the wire electrode 2 and the workpiece 3 from an energizing device such as an upper energizing pin 4 and a lower energizing roller, and a discharge pulse current flows. Since the machine is moving above the workpiece, the area around the machining gap formed between it and the workpiece 3 is of course exposed to high temperatures, as well as the contact between the upper current-carrying pin 4 and the current-carrying device such as the lower current-carrying roller. The wire electrode 2 between the two is easily heated to a high temperature by being heated by electricity, and therefore, as described above, it is cooled by supplying machining fluid. However, the opening 51 in the lower nozzle main body 5 is not necessarily required because the machining fluid flowing down from the machining section is often sufficient for the lower energizing device.
In particular, the current is flowing between the current-carrying pin 4 and the wire electrode 2 while they are in sliding contact, and there is a wedge-shaped minute gap 2A between the current-carrying pin 4 and the wire electrode 2 as shown in FIGS. 2A and 2B. , 2B are formed, the machining fluid supplied to these minute gaps 2A and 2B is exposed to water vapor, etc. due to the wire electrode 2 or the current-carrying pin 4 becoming hot, or being heated by electricity in the sliding gap. It often became stagnant in the form of bubbles in the gaps. Once the air bubbles have accumulated, the gaps 2A and 2B are wedge-shaped and narrow, so even the injection processing liquid from the opening 51 cannot release the air bubbles, especially in the gap 2.
The bubbles on the B side increase the contact or current conduction resistance between the wire electrode 2 and the current-carrying pin 4, increasing the amount of heat generated,
Furthermore, it becomes impossible to cool down the heat generated during this period, and the wire electrode 2 may be disconnected at the current-carrying pin 4 portion due to heat generation or abnormal discharge occurring in the portion, which is a problem. Note that in the case of a lower current-carrying pin or roller, the bubbles in the gap 2A are a problem, but the bubbles in the gap 2A tend to rise and separate from between the pin or roller and the wire electrode; Since the wire does not get between the wire electrode and the lower current carrying device, there are relatively few problems with the lower current carrying device, and therefore, the present invention can be applied to the lower current carrying device as necessary, as will be described later.

[Purpose and structure of the idea]

The present invention was made in order to solve the above-mentioned conventional problems, and the present invention is made of a porous body for the energizing device, especially the part of the upper energizing pin that comes into contact with the wire electrode,
It is an object of the present invention to provide a current-carrying device for wire cut electrical discharge machining, which cools the gap between a wire electrode and the current-carrying device by exuding machining fluid from the inside, and prevents the generation of bubbles.

〔Example〕

The present invention will be explained below with reference to the illustrated embodiments.

The embodiment shown in FIGS. 3 to 5 is provided in place of the current-carrying pin 4 in FIGS. 1 and 2, and the other configuration is the wire cut electrical discharge machining shown and explained in FIG. This is the same as the device, and illustrations and explanations will be omitted. FIG. 3 is an enlarged side view showing a state in which the energizing device 10 and the wire electrode 2 are in contact with each other, which is an embodiment of the present invention, and FIG. 4 is an enlarged front view of the same. The current supply device 10 is fixed to a support member 13 of the wire-cut electric discharge machining apparatus via a mounting arm 20 extending perpendicularly to the wire electrode 2. This mounting arm 20 has a disk-shaped base 3.
0 is fixed to the base portion 30, and the base end of a fixed shaft 40 is fixed to this base portion 30. Both ends of the fixed shaft 40 are
The proximal end side is a threaded part 40a, and the distal end side is a threaded part 40.
b, and a nut 50 is attached to the threaded portion 40a.
a and 50b are engaged. After engaging the nuts 50a and 50b with the threaded portion 40a and fixing the nut 50b at a desired position, the nut 50a is further rotated toward the nut 50b.
0a and 50b are tightened together, and the nut 50
a and 50b are fixed at desired positions. Further, a collar 50c adjacent to the nut 50b is inserted into the fixed shaft 40, and this collar 50c
A cylindrical current-carrying member 60 is fitted onto the fixed shaft 40 adjacent to the cylindrical current-carrying member 60 . The current-carrying member 60 is a cylindrical member with an inner diameter that contacts the outer peripheral surface of the intermediate portion of the fixed shaft 40 without a gap, and is made of a sintered current-carrying member such as porous cemented carbide. The material of the current-carrying member 60 is as follows:
Suitable materials include Cu, WC, TiC, TiN, Pd, Ni, etc. as main materials. In this example, WC
(tungsten carbide) was sintered with Ni (nickel) as a binding material. In addition, the cylinder body 6
0 is supplied with voltage pulses from a processing power source (not shown), and is adapted to apply voltage pulses to the wire electrode 2. That is, for example, one output terminal of the processing power source may be inserted between the nuts 50a and 50b, between the washer 70 and the current-carrying member 60, and tightened, or may be insulated and connected to the mounting arm 20 or the member 13 side. be. Furthermore, a washer 70 is inserted into the fixed shaft 40 adjacent to the current-carrying member 60, and a wing nut 80 that abuts the washer 70 is engaged with a threaded portion 40b at the tip of the fixed shaft 40. In this way, the fixed shaft 40 has nuts 50a,
50b, collar 50c, cylindrical current-carrying member 60, washer 70, and wing nut 80 are engaged, and the nut 50
a, 50b are fixed in a predetermined position, and the nuts 50a, 50b are tightened by tightening the wing nut 80 that is engaged with the threaded part 40b at the tip on the opposite side and moving toward the nuts 50a, 50b. butterfly nut 80
A collar 50c, a current-carrying member 60, and a washer 70 are placed between the
The electrically conductive member 60 is held in a predetermined position by sandwiching the electrically conductive member 60. Further, a hollow portion 90 is formed inside the fixed shaft 40, and this hollow portion 90 is formed inside the fixed shaft 40.
It communicates with an injection hole 90a opened at the tip.
Further, a plurality of holes 90b are formed in the outer peripheral surface of the intermediate portion between the hollow portion 90 and the fixed shaft 40 so as to be uniformly distributed. The vicinity of the injection hole 90a at the tip of the fixed shaft 40 is configured such that, for example, a pipe from a machining fluid supply device installed in a wire-cut electrical discharge machining device or a separately provided pipe 90c is attached. The machining fluid enters into the hollow part 90 through the injection hole 90a, and flows from the hollow part 90 into the hole 9.
It is designed to be supplied to the inside of the cylindrical current-carrying member 60 through 0b. The machining liquid supplied to the inner peripheral wall of the current-carrying member 60 is a porous current-carrying member 6.
0 and exudes to the outer surface of the current-carrying member 60.

When the current-carrying device 10 configured as described above is installed in a wire-cut electrical discharge machining apparatus, the heat generated between the current-carrying device and the wire electrode 2 is cooled, and the generation of air bubbles between the two is prevented. Further, the generated air bubbles can be removed by pushing them out or the like. To be more specific, as shown in FIGS. 3 and 4, the wire electrode 2 is brought into contact with the current-carrying member 60 of the current-carrying device 10 according to a pressing pin (not shown) or a wire path in the relevant portion, and processing is started. As the wire electrode 2 is moved, electricity is supplied from the current-carrying member 60, and at the same time, machining fluid is supplied under pressure from the pipe 90c or the like to the hollow portion 90 within the fixed shaft 40. The machining fluid supplied into the hollow portion 90 is supplied into the cylindrical current-carrying member 60 that is in contact with the outer surface of the fixed shaft 40 through the hole 90b. As described above, since the current-carrying member 60 is a porous body with wide grain intervals, the machining liquid permeates into the cylindrical current-carrying member 60 under pressure and leaks out from the surface of the current-carrying member 60 . Therefore, the machining fluid exuding from inside the current-carrying member is always supplied between the current-carrying member 60 and the wire electrode 2, and the machining liquid is always supplied to the inside of the current-carrying member 60 even in gaps where bubbles and the like are likely to occur. Since the air is supplied from the air, the cooling efficiency is good and it is possible to prevent the generation of air bubbles.

As mentioned above, when the cylindrical body was made of sintered WC with a Ni binding material and a machining current of 8 A was passed through the cylindrical body, the temperature of the current-carrying member 60 was 62°C.
When the machining fluid was supplied from inside the fixed shaft 40 to the inside of the current-carrying member 60 at a pressure of approximately 3 kg/cm ² and the machining fluid was circulated at a rate of approximately 0.4/min, the temperature of the current-carrying member 60 could be set to 18°C. did it. Similarly, the current-carrying member 60 is made of TiN and TiC at a ratio of 50:50, 12% Cu is added thereto, and the porosity is 42, which is sintered after pressure molding.
% alloy, substantially the same results as above could be obtained.

Further, the cylindrical current-carrying member 60 is fitted onto the fixed shaft 40 and can be rotated by loosening the thumbscrew 80. Therefore, when the portion in contact with the wire electrode 2 is worn out, the cylindrical current-carrying member 60 is rotated and the wire electrode 2 It is also possible to change the contact area with.

[Devising effect]

As explained above, the present invention consists of a hollow body into which machining fluid is supplied, a fixed shaft having a hole penetrating into the periphery, and a porous body that is fitted into the fixed shaft and has a wire electrode. A energizing device for wire cut electric discharge machining is constructed from the cylindrical energizing member that is brought into contact with the cylindrical energizing member. Therefore, instead of supplying machining fluid from the outside of the current-carrying device and the wire electrode as in the past, the machining fluid is supplied from the inside of the cylindrical current-carrying member that is in contact with the current-carrying device, specifically the wire electrode, to the outside of the current-carrying member. Since the processing fluid is supplied to even the smallest gap between the current-carrying device and the wire electrode, it is possible to achieve effective cooling and prevent air bubbles from forming in the gap. be.
Therefore, abnormal discharge and the like do not occur, and disconnection of the wire electrode can be prevented. Furthermore, since the portion of the energizing device that comes into contact with the wire electrode can be cooled by the machining liquid that seeps from inside, it is possible to extend the life of the energizing device itself. Note that in carrying out the present invention, there is no hindrance to the use of a current-carrying device cooling means (opening 51) as shown in FIG. In addition to those made of current-carrying members, for example, those having a structure in which opening windows are formed at predetermined intervals along the circumferential arc direction of a conductive alloy cylinder, and pieces of current-carrying members are attached watertightly so as to close the opening windows. Of course, various modifications are possible.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a part of a conventional wire-cut electric discharge machining device, Fig. 2 A and B are enlarged side views and front views showing the wire electrode and energizing pin portion, and Fig. 3
The figure is a side view of an energizing device showing an embodiment of the present invention.
Figure 4 is a front view of the energizing device, Figure 5 is Figure 4-
FIG. 2... Wire electrode, 3... Workpiece, 10...
Current-carrying device, 40... Fixed shaft, 60... Cylindrical current-carrying member, 90b... Through hole.

Claims (1)

[Claims for Utility Model Registration] 1. When performing electric discharge machining by applying intermittent voltage pulses between the workpiece 3 and the wire electrode 2,
The energizing device 10 for wire-cut electrical discharge machining, which energizes by contacting a wire electrode, includes a fixed shaft 40 which is a hollow cylindrical body into which machining fluid is supplied and has a plurality of through holes 90b in the circumferential portion. , a cylindrical current-carrying member 60 which is a cylindrical porous body and is brought into contact with the wire electrode 2 on the circumferential side thereof while traveling in a direction substantially perpendicular to the axial direction; An energizing device for wire cut electrical discharge machining, characterized in that it is coaxially fitted into a portion of the fixed shaft 40 in which the through hole 90b is provided. 2. The energizing device is a wire-cut electric discharge machining apparatus in which the axis of the wire electrode of the machining section substantially coincides with a vertical line, and the wire electrode is renewed and fed from the upper surface side to the lower surface side of the workpiece. An energizing device for wire cut electric discharge machining according to claim 1, which is an energizing device on the upper surface side of a workpiece. 3. The energizing device for wire cut electrical discharge machining according to claim 1, wherein the cylindrical porous energizing member is a sintered body of an alloy. 4. Wire-cut electric discharge machining according to claim 1, wherein the cylindrical porous current-carrying member is non-porous except for the contact portion between the current-carrying part and the wire electrode and the vicinity thereof. energizing device. 5. The energizing device for wire cut electric discharge machining according to claim 1, wherein the machining fluid is supplied into the cylindrical energizing member by pressurized supply means at a predetermined pressure.