JPH0441129A - Wire electric discharge machine - Google Patents

Abstract

PURPOSE:To deliver and feed an amount of a bar electrode consumed during electric discharge machining properly equivalent to the consumed amount by providing first and second grip units for carrying out gripping and releasing action on the bar electrode for machining narrow holes. CONSTITUTION:A case 30 to store a bar electrode 34 for machining a narrow hole, a means 33 to turn this case 30, first and second gripping means 35, 36 for gripping and releasing the bar electrode 34 in accordance with a narrow hole machining program and a delivery and feed means 37 for moving the bar electrode 34 in the shaft direction in connection with the motion of these gripping means are provided. Subsequently, the bar electrode 34 is delivered and fed every specific period of time by way of repeatedly actuating these first and second grip means 35, 36 and the delivery and feed means 37 in accordance with the narrow hole machining program.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire electrical discharge machine, and more particularly to a wire electrical discharge machine equipped with a thin electrical discharge machining electrode device.

[Prior Art] FIG. 9 is a schematic diagram showing an example of the configuration of a conventional electrical discharge machine for machining small holes. In the figure, (1) is a bet, (
2) is the column, (3) is the Z-axis moving guide provided at the tip of the column (2), (4) is the processing head, and (5) is the processing head (4) connected to the Z-axis moving guide (3). A Z-axis servo motor (6) driven via a movable part is a workpiece. (7) is an X-Y table on which the workpiece (6) is placed and moved in the X-Y direction, (8) is a processing tank, (9) is a rod-shaped electrode, and (10) is an electrode (9). (11) is a power source for applying a pulse voltage between the workpiece (6) and the electrode (9); (12) is a through hole provided in the center of the electrode (9); This is a pump for pumping machining fluid to the machining section.

In the electric discharge machine configured as described above, first, the electrode (9) is attached to the electrode chuck (10). Ordinary electrodes for small hole machining use a copper alloy with a diameter of about 0.5 to 5 mm.
A through hole is provided in the center or at an eccentric position through which the machining fluid passes. Next, place the workpiece (6) on the X-Y table (
7) Place and fix it on top and connect it to the power supply (11), drive the pump (12) to inject the machining liquid into the machining part through the through hole of the electrode (9), and connect the Z-axis servo motor (5). ) while lowering the rotating electrode (9) by the drive of the electrode (9).
A small hole is machined using the discharge energy generated between the gap between the machine and the workpiece (6).

The processing powder scattered by the above processing is discharged from the upper part of the workpiece (6) into the processing tank (8) through the gap, together with the processing liquid spouted into the processing section.

In addition, if a short circuit occurs between the tip of the electrode (9) and the processed part of the workpiece (6) during processing, this short circuit is detected and the electrode (9) is slightly raised to Machining proceeds while maintaining a predetermined discharge gap.

[Problems to be Solved by the Invention] The conventional electric discharge machine as described above is a processing device dedicated to machining small holes, but the functions it has are similar to those of ordinary electric discharge machines for die-sinking. Since this is similar to the above, a corresponding mechanism, control means, etc. are required for this purpose, which poses problems such as the device being complicated and expensive.

This invention was made to solve the above-mentioned problems, and aims to provide a wire electrical discharge machine equipped with a small hole machining electrode device that provides excellent controllability and can be manufactured at low cost. [Means for Solving the Problems] A wire electrical discharge machine according to the present invention includes a case for accommodating a rod electrode for machining a small hole, means for rotating the case, and a case for accommodating a rod electrode for machining a small hole. The first step is to grasp and release the . A small hole machining electrode device is provided having second gripping means and feeding means for moving the rod electrode in the axial direction in conjunction with the operation of the gripping means.

[Function] The fine-machined electrode device according to the present invention has a first grip for gripping the rod electrode and releasing the grip according to the fine-hole machining program.
．． The rod electrode is fed at predetermined time intervals by the second gripping means and the repeated movement of the feeding means in the axial direction of the rod electrode, which operates in conjunction with the operation of the gripping means.

[Example 1] An example of the present invention will be described below with reference to FIGS. 1 to 8. FIG. 1 is a schematic diagram showing the overall configuration of this embodiment. In the figure, (13) is the wire electrode sent out from the supply bobbin (14), and (15) is the electrode brake (1
5a), a brake roller (lea) which is directly connected to the wire electrode (13) and applies a predetermined tension to the wire electrode (13).

(18b) and (16c) are wire electrodes (1
3) is an idler that changes the running direction, (17) is an upper guide, (8) is an upper conductor, (19) is a lower guide,
(20) is a lower conductor, which is arranged inside the upper and lower machining liquid jetting nozzles (21) and (22), respectively. (24) is a pump for supplying machining fluid (23), (24a) and (24b) are switching valves for machining fluid (23), and (25) is wire electrode (13) and workpiece (2B).
A power source unit (25a) is used to generate a discharge between the two.

The wire electrode (13) is supported by an upper guide (17) and a lower guide (19), and faces the workpiece (2B) in a predetermined direction. (27) is a wire feed roller, (28) is an automatic wire insertion and connection device, and (40) is a fine-sized machining electrode device according to the present invention, which is fixed to the upper machining liquid jetting nozzle head (29).

FIG. 2 is a partial sectional view showing an outline of the small hole machining electrode device, and FIG. 3 is a longitudinal sectional view showing the configuration of the main part thereof. In both figures, (30) is a cylindrical case, which is supported by a bearing (32) in a mount (31) fixed to the upper machining liquid jet nozzle head (29), and is driven by an electric motor in the direction of the arrow. be done. (34) is the electrode rod in use installed inside the case (30), and (34a) is the working fluid (23).
) is an inlet, and (34b) is an outlet for the machining fluid (23). (34e) is a spare electrode rod housed in the case (30). (33) is an electric motor that is installed on the top of the mounting base (31) and drives the case (30), and the rotor (33a) fixed to the case (30) and the coil (
33b).

(35), (3B), (37) are electrode rods (34
) to send out the 1st and 2nd. The movable elements (35a), (
38a), (37a), and a coil (35b) disposed around the outer periphery of the case (30) in the mounting base (31).
, (36b), (37b), and spring (15c),
(He).

(S7c), excitation of coils (85b), (36b), (37b) in the directions of arrows B, C, and D, respectively, and compression springs (S5c), (He), (3
It operates by the repulsive force of 7e).

Among the above electromagnets (35), 36), and (37), the first one. The movers (35a) and (38a) of the second electromagnets (35) and (38) have the same configuration. For example, the mover (35a) has a three-part structure as shown in FIG. The rod electrode (34) is gripped with an even pressing force by a compression spring (35c) provided in the section. However, this mover (35a) is restricted from moving in the longitudinal direction of the case (30). (38) is a guide for the electrode rod (34) which is arranged to be able to slide vertically at the bottom of the case (30), (39) is the intake port for the machining fluid (40), and (41) is for the motor (33). Brush for power supply, (4f
1) is a cylindrical member made of an elastic material to prevent leakage of the machining fluid (23), and (47) is a fluid supply hole.

In the electric discharge machining apparatus configured as described above, each operation described below is symbolized as follows: A on: The movable element (3) of the first electromagnet (35) is moved by the spring (35c).
5a) to grip and fix the rod electrode (34) (coil ($5b)
) is non-energized).

Aofr: mover (38a) of second electromagnet (3B)
to release the rod electrode (34) (the coil (38b) is excited and attracts the mover (38a)).

B on: The second electromagnet (36
) grips and fixes the rod electrode (34) with the mover (38a) of the
Coil (aab) is non-excited).

Boff: The rod electrode (34) is released by the mover (38a) of the second electromagnet (3B) (the coil (36b)
Aspirate 8a)).

Con: The rod electrode (34) is moved in the feeding direction by the mover (17a) of the third electromagnet (37) (the coil (37b) is excited).

Cofr: ba b (37c)! ,: The rod electrode (34) is returned to its original position by the mover (37a) of the third electromagnet (37) (the coil (37b) is de-energized).

The relationship between each of the symbolized actions as described above is shown in a time series as shown in the diagram of FIG. That is, at time T1 according to the narrow large angle nib program, the movable element (35a) of the first electromagnet (35) and the movable element (35a) of the second electromagnet (36)
8a) grips the rod electrode (34), and at the same time as time T2 shifts, the movable element (35a) of the first electromagnet (35) releases its grip, and the movable element (35a) of the third electromagnet (37)
37a) lowers the rod electrode (34) in the axial direction,
During time T2, the mover (H) holding the rod electrode (34)
a) and the rod electrode (34) is lowered by the 2 minute stroke shown in FIG. 3 to deliver the rod electrode (34). Simultaneously with the transition to time T3, the movable element (35a) also grips the rod electrode (34) and maintains the position of the rod electrode (34). Simultaneously with the transition to time T4, the grip of the bar electrode (34) on the movable element (38a) is released, and the third electromagnet (27) is energized to return the movable element (a7a) to its original position. T4
Inside, the rod electrode (34) is held and remains at the same position for the above-mentioned time T3. Next, at the same time as moving to time T5, the mover (
36a) grips the rod electrode (34), and during this time T5 the rod electrode (34) remains in the position it was delivered at time T3.

After the time T, the same operation as the above times T1 to T4 is repeated, and the rod electrode (34) is fed with a predetermined stroke g each time.

Next, details of the small hole machining will be explained. First, close the changeover valve (24a) for the machining fluid (23) and open (24b), and turn the changeover switch (25a) on the small hole machining electrode device (
28) Insert it on the side. Next, the guide (38
) is lowered close to the workpiece (2B) by pneumatic means (not shown), and the rod electrode (34) is lowered by the above-mentioned operation.
send out. After the rod electrode (34) senses the workpiece (26), a Z-axis servo (not shown) moves the workpiece (
26) maintain a certain gap between

Then, inject the machining fluid (23) from the inlet (39) into the case (
30) and the inlet (34a) of the rod electrode (34).
At the same time, the case (30) is rotated by the motor (33), and electrical discharge pressure from the power source of the wire electrical discharge machine is applied via the brush (41). Then, electrical discharge machining of a small hole is performed between the rod electrode (34) and the workpiece (2B). Note that switching of the switching valves (24a) and (24b) for the machining fluid (23) and switching of the power switch (25a) are performed automatically. In addition, short-circuit back during discharge and voltage control between electrodes are all shared with the wire electric discharge machine.

Small hole machining progresses by the drive of a Z-axis servo (not shown), and when the rod electrode (34) is exhausted, the machining is temporarily stopped, the remaining rod electrode (34) is discarded, and a spare rod in the case (30) is used. Send out the electrode (34c) and start electric discharge machining again.
It passes through the small hole (28a). When the above-mentioned fine hole machining is completed, the rod electrode (34) is returned to its original position by the above-mentioned reverse operation, and the guide (38) is raised and retracted by the air means, and the fine hole machining is completed.

After completing the small hole machining as described above, turn on the power switch (25a) and switching knob (24a) shown in Figure 1.
, (24b) is switched to a normal electric discharge machine, the wire electrode (13) is inserted into the small hole (26a) made in the workpiece (2B) by the automatic wire insertion and connection device (28), and the wire electrode (13) is inserted into the workpiece (2B). 26) Start electrical discharge machining.

In addition, as a method for automatically extracting the processed product obtained from the workpiece (26) and its scrap, Japanese Patent Application No.
By interlocking with the apparatus described in the specification and drawings of No. 278680, a series of steps such as drilling small holes, inserting electrode wires, and automatically processing a processed product can be incorporated into a numerical control program.

In order to prevent the machining fluid (23) from leaking from the gap between the rod electrode (34) and the outer periphery of the case (30), a mechanical seal is installed in the recess provided in the mounting base (31) as shown in Figure 6. (45), a cylindrical member (4B) made of an elastic material is placed inside the case (30), and fluid pressure is applied through the hole (47) drilled in the mounting base (31). The shaped member (46) is deformed as shown by the broken line, and the rod electrode (
If the structure is such that it comes into pressure contact with the machining fluid (23)
can be supplied from the inlet (34a) to the outlet (34b) at the tip without leaking to other parts.

In the above embodiment, an electromagnet was used as a means for obtaining a driving force for gripping and supplying the rod electrode (34), but the means for obtaining this driving force is not limited to an electromagnet, and for example, As shown in FIG. 7, the first. second and third electromagnets (35),
A piezoelectric element (36), corresponding to the function of (37) (
4g), (49), (50) in case (30)
The rod electrode (34) may be gripped and fed in accordance with a signal via lead wires (not shown) disposed inside and connected to each of these lead wires (not shown). Further, fluid pressure may be used to obtain similar driving force for gripping and feeding.

Further, in the above embodiment, the electric motor (33) is used as a drive source for rotating the case (30), but as shown in FIG. 8, the blade (51) fixed to the case (30) ) may be injected from a nozzle (52) to rotate the case (30).

In addition, in the above embodiment, the case of small hole machining before the start of wire electric discharge machining was explained, but the gripping and feeding operations of the rod electrode (34) and the relative movement in the Z-Y direction with the workpiece (26) If it is incorporated into the NC program, it can also be used as an electrical discharge machine for three-dimensional machining.

[Effects of the Invention] As described above, according to the present invention, the first... The second gripping means and the feeding means for moving the rod electrode in the axial direction in correlation with these operations are provided, and the rod electrode is fed at predetermined time intervals, so that the rod electrode is not worn out during electrical discharge machining. It is possible to obtain a wire electric discharge machine equipped with an inexpensive small-hole machining electrode device with good controllability and which can feed the rod electrode appropriately in accordance with the amount of rod electrode consumption.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the overall configuration of a wire electrical discharge machine according to an embodiment of the present invention, and FIG. 2 is a longitudinal section showing the overall configuration of the small hole machining electrode device in FIG. 1, which is partially shown in cross section. 3 is a sectional view showing an embodiment of the main part thereof, FIG. 4 is a perspective view of an embodiment of the mover, and FIG. 5 is a diagram for explaining the operation of the invention in chronological order. FIG. 6 is a vertical sectional view showing a part of FIG. 3 in an enlarged manner, FIGS. 7 and 8 are sectional views and perspective views of other embodiments of the present invention, and FIG. 9 is a conventional thin hole. FIG. 1 is a schematic diagram showing the overall configuration of a processing device. In the figure, (23) is the machining fluid, 2B) is the workpiece,
(28) is a small hole machining electrode device, (30) is a case, (3
3) is the electric motor, (34) is the rod electrode, and (35) is the first
(36) is the second electromagnet device, (37)
is the third electromagnetic device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] A cylindrical case in which a tubular rod electrode for electrical discharge machining of a small hole is housed in parallel to and close to the feeding direction of the wire electrode, a means for rotating the case, and a means provided on the outer periphery of the rod electrode. first and second gripping means for gripping and releasing the rod electrode according to a program for machining the small hole; and a feeding means for moving the rod electrode in the axial direction in conjunction with the operation of the gripping means. A wire electrical discharge machine characterized by being equipped with a small hole machining electrode device.