JP2008080417A - Electric discharge machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stable electric discharge machining by suppressing the generation of bubbles in a dispatch tank by reducing jetting pressure of working fluid to be jetted into the dispatch tank. <P>SOLUTION: An electric discharge machine 1 comprises a machining bath 8 for machining a workpiece W while being immersed in the working fluid, a storage tank 10 for collecting and storing the working fluid existing in the machining bath 8, and the dispatch tank 20 which stores the working fluid jetted from the storage tank 10 via a supply pump A and dispatches the stored working fluid to the machining bath 8, wherein the dispatch tank 20 comprises a jetting port 23 of the working fluid to be jetted from the storage tank 10 and a chamber 30 for covering the jetting port 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric discharge machining apparatus including a rapid feed tank that rapidly feeds a machining liquid to a machining tank.

In general, an electric discharge machining apparatus generates a continuous discharge by applying a required machining voltage between a work electrode and a tool electrode that are arranged to face each other with a predetermined electric discharge machining gap (hereinafter referred to as a gap). The workpiece and the tool electrode are moved relative to each other, and the workpiece is machined into a desired shape. The discharge energy is reduced due to machining waste and tarted machining fluid generated between the electrodes during machining ( In order to avoid discharge delays, etc., the workpiece is immersed in a machining tank filled with a machining fluid, and electrical discharge machining is performed while continuously removing machining debris generated between the electrodes by the machining fluid.
In this electric discharge machining apparatus, as disclosed in Patent Document 1 to Patent Document 3, an expedited tank (an auxiliary tank in Patent Document 1, a fill tank in Patent Document 2, and a patent tank 3 in a position above the machining tank) Sub-tanks) are often provided, and at the start of machining, in order to quickly send the machining fluid to the machining tank in a short time, the rapid feed line (rapid flow path) that connects the rapid feed tank and the machining tank is opened and the head difference It was set as the structure which rapidly sends a processing liquid to a processing tank using.

International Publication Number WO01 / 036139 JP-A-5-4117 JP-A-5-42424

By the way, in recent years, from the viewpoint of cost reduction, the capacity of the express tank has been set to be small with respect to the required express quantity, and operation has been made to eject the processing liquid into the express tank while sending it to the processing tank. Even when the machining fluid must be ejected to the rapid feed tank with the ejection pressure, and the machining fluid is ejected from below the liquid level when the rapid machining tank is filled with the predetermined machining fluid, the large ejection pressure of the machining fluid acts. As a result, the liquid level jumped greatly in the express tank and air was sometimes involved.
In recent years, oil-based machining fluids are often used in order to meet the demands of high machining accuracy from customers. When machining fluids entrain air in the processing of oil-based machining fluids, Large viscosity may occur and a large amount of bubbles may be generated in the express tank. And when this bubble penetrate | invaded into a processing tank, there existed a possibility of obstructing stable electrical discharge machining, such as making it difficult to visually recognize the inside of a processing tank or generating an arc discharge during processing.

The present invention has been made in view of such circumstances, and it is possible to realize stable electric discharge machining by relaxing the jet pressure of the machining liquid jetted to the rapid feed tank and suppressing the generation of bubbles in the rapid feed tank. An object is to provide an electric discharge machining apparatus.

In order to achieve the above object, the invention of claim 1 includes a processing tank that immerses and processes a workpiece in a processing liquid, a storage tank that collects and stores the processing liquid in the processing tank, and a supply pump from the storage tank. In the electric discharge machining apparatus that includes the expediting tank that stores the working fluid ejected via the expelling tank and that expedites the stored working fluid to the machining tank, the expediting tank relaxes the pressure of the working fluid ejected from the storage tank. A structure is provided.

According to the present invention, the expediting tank is provided with a pressure relaxation structure that relieves the pressure of the working fluid ejected from the storage tank, and therefore, the expelling pressure of the working fluid is relaxed in the expediting tank and the liquid surface jumps up. Generation of bubbles can be suppressed. Note that “the pressure of the machining fluid ejected from the storage tank” includes the pressure of the upward flow generated when the machining fluid ejected from the storage tank collides with the bottom surface of the rapid-feed tank. Further, the “pressure relaxation structure” includes various structures that relieve the pressure of the processing liquid ejected from a storage tank such as a chamber, a baffle plate, or an elastic member.

The invention of claim 2 stores a machining tank that immerses a workpiece in a machining liquid, a storage tank that collects and stores the machining liquid in the machining tank, and a machining liquid that is ejected from the storage tank via a supply pump. In addition, in the electric discharge machining apparatus that includes a rapid-feed tank that rapidly sends the stored machining liquid to the machining tank, the rapid-feed tank includes a chamber that covers the jet port and has a jet port for the machining liquid ejected from the storage tank. It is characterized by that.

According to the present invention, since the expediting tank has the ejection port for the machining liquid ejected from the storage tank and the chamber for covering the ejection port, the machining liquid ejected from the storage tank collides with the inner surface of the chamber. And the jetting pressure of the machining fluid can be relaxed with certainty.

A guide plate is provided inside the chamber so that the machining liquid ejected from the ejection port collides with the inner surface of the chamber facing the ejection port, and the collided processing fluid also collides with the inner surface of another chamber other than the inner surface. If so, it is possible to increase the collision efficiency of the jetted machining fluid to the inner surface of the chamber, and it is possible to more reliably alleviate the jetting pressure of the machining fluid.

If the spout is provided at the bottom of the express tank, the flow path until the processing liquid ejected from the spout reaches the liquid level can be made longer, so that the ejected processing liquid reaches the liquid level. By this time, the ejection pressure is further relaxed (claim 4).

According to the present invention, it is possible to suppress the generation of bubbles in the rapid-feed tank and realize stable electric discharge machining.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a right side view schematically showing the electric discharge machining apparatus 1 according to the first embodiment of the present invention.
Referring to FIG. 1, the outline of the electric discharge machining apparatus 1 will be described. The electric discharge machining apparatus 1 includes a bed 2 that forms the base of the apparatus 1, a column 3 that stands on the rear upper surface of the bed 2, and an upper surface of the column 3. A ram 4 mounted on the front surface of the ram 4, a machining head 6 mounted on the front surface of the ram 4 and provided with a tool electrode 5, a surface plate 7 provided on the front side of the bed 2 and having a work W disposed thereon, and a surface plate 7, a processing tank 8 for immersing the workpiece W in the processing liquid, a work table 9 on which the processing tank 8 is placed, and the sewage in the processing tank 8 is collected and clarified and stored, and the stored processing It has a storage tank 10 for supplying the liquid to the processing tank 8, performs electric discharge machining while generating electric discharge between the electrodes by a power supply device (not shown), and the processing liquid between the processing tank 8 and the storage tank 10. The processing tank 8 is filled with a clear processing fluid. The

An express tank 20 is provided above the processing tank 8 via a gantry 11, and the express tank 20 is processed liquid ejected from a storage tank 10 via a supply pump A as shown in FIG. Is stored, and the stored machining fluid is rapidly sent to the processing tank 8 via the rapid flow path B while utilizing the head difference.
As shown in FIG. 3, the expedited tank 20 has a rectangular parallelepiped tank main body 21, and a processing liquid spout 23 is provided on the rear side of the bottom 22 of the tank main body 21.

The machining liquid outlet 23 is covered with a chamber 30. As shown in FIG. 5 which is a sectional view taken along the line II in FIGS. 4 and 4, the chamber 30 is formed in a substantially box shape. Protrusions 31 projecting forward and backward respectively are provided at the front and rear portions of the chamber 30, and a machining liquid outlet 32 is formed at the lower end of the protrusion 31.

An opening 34 is formed at the center of the bottom 33 of the chamber 30, and a guide plate 35 is provided inside the chamber 30. The guide plate 35 is provided so as to stand upward from the opening end of the bottom portion 33, and separates the internal space of the chamber 30 including the opening 34 and the internal space including the outflow port 32, and the guide plate A gap 36 is provided between the upper end of 35 and the upper portion of the chamber 30.

That is, by providing the guide plate 35 inside the chamber 30, the flow path 38 connecting the opening 34, the gap 36, and the outlet 32 is formed, and the chamber 30 is rapidly sent so that the opening 34 includes the machining liquid outlet 23. In the state provided at the bottom 22 of the tank 20, the processing liquid ejected from the ejection port 23 flows out of the chamber 30 along the flow path 38.

In this outflow process, the machining liquid collides with the upper inner surface of the chamber 30 facing the jet port 23, further turns the flow path in the horizontal direction, collides with the front inner surface or the rear inner surface, and flows further downward. Since the path turns and collides with the inner surface of the bottom of the chamber 30, the provision of the guide plate 35 can increase the collision efficiency of the ejected machining fluid to the inner surface of the chamber 30 and reliably reduce the ejection pressure of the machining fluid. Thus, the generation of bubbles due to the liquid level jumping up inside the express tank 20 can be suppressed.

A weir 37 is provided at the other end of the bottom 33 of the chamber 30, and the machining fluid flowing out from the outlet 32 also collides with the weir 37, so that the ejection pressure of the machining fluid is further relaxed. The machining liquid reaches the liquid level after colliding with the weir 37 and reaches the liquid level. In the present embodiment, the ejection port 23 is provided at the bottom 22 of the expedited tank 20, and the machining liquid is at the liquid level. Since the flow path until reaching the point is set longer, the ejection pressure is further relaxed until the processing liquid reaches the liquid level.

Next, the method of rapid delivery of the machining fluid by the rapid delivery tank 20 described above will be described with reference to FIGS. 2 and 3 again.
First, the supply pump A is activated at the time of processing in the previous process or at the start of processing, and the processing liquid is ejected from the storage tank 10 to the expedited tank 20 so that the expelling tank 20 is filled with the working liquid to a predetermined water level in advance. Keep it.

Then, when the processing start setup is completed, the rapid flow path B is opened, and the processing liquid is rapidly transferred to the empty processing tank 8 while using the head difference. Since the capacity of the expediting tank 20 is set to be smaller than the required expedited amount, the processing liquid is expedited from the storage tank 10 by activating the supply pump A at the same time as the expedited amount so that there is no shortage of the expedited amount. This is performed while the processing liquid is jetted into the tank 20. When the machining liquid is ejected to the rapid delivery tank 20, the chamber 30 provided in the rapid delivery tank 20 acts, so that the generation of bubbles due to the liquid surface jumping up inside the rapid delivery tank 20 can be suppressed.
Subsequently, when the processing tank 8 is filled with a necessary amount of the processing liquid, the supply pump A is stopped and the rapid flow path B is closed to terminate the rapid supply of the processing liquid to the processing tank 8.

Next, second to third embodiments of the present invention will be described with reference to FIGS.
The second embodiment of the present invention employs a configuration in which an elastic member 40 is provided in place of the chamber 30 provided in the express tank 20 of the first embodiment. Specifically, as shown in FIG. 6A, an elastic member 40 is provided via a support 41 so as to face the processing liquid ejected from the ejection port 23 of the expedited tank 20.

This elastic member 40 is composed of a member having elasticity, water absorption and water permeability, such as a sponge-like member, and has an opening at the bottom as shown in FIG. 7, and the top is closed by a flat plate. It is stored in the storage box 40a. Therefore, since the machining liquid ejected to the rapid delivery tank 20 collides with the elastic member 40 through the opening of the storage box 40a, the ejection pressure of the machining liquid can be surely reduced by the action of the elastic force of the elastic member 40. .
In addition, when the jetting pressure of the machining fluid is relatively small, a baffle plate 50 may be provided instead of the elastic member 40 as shown in FIG.

3rd Embodiment of this invention has shown the pressure relaxation structure employ | adopted when the working fluid spouts downward from an upper position in the express tank 20 of 1st Embodiment. Specifically, as shown in FIG. 8A, a machining liquid ejection port 23 ′ is provided in the vicinity of the bottom 22 of the rapid-feed tank 20. Thereby, since the flow path until the machining liquid ejected from the ejection port 23 ′ reaches the liquid level is set longer, it is possible to relax the ejection pressure of the machining liquid and reach the liquid level. In addition, even when the machining liquid is ejected to the empty rapid-feed tank 20, it is possible to reduce an impact when the machining liquid ejected from the storage tank 10 collides with the bottom surface of the rapid-feed tank 20.

Further, an elastic member 41 composed of a sponge-like member is placed in the vicinity of the ejection port 23 ′ so that the machining liquid ejected from the ejection port 23 ′ faces the upward flow generated by colliding with the bottom surface of the rapid delivery tank 20. Is provided. Thereby, the upward flow and the elastic member 41 can be made to collide reliably and the pressure of this upward flow can be relieved. When the pressure of the upward flow is relatively small, a baffle plate 60 may be provided instead of the elastic member 41 as shown in FIG. Moreover, as shown in FIG.8 (c), it is good also as providing the baffle plate 60 and also providing the elastic member 41 in the bottom face of the expedited tank 20 facing the jet nozzle 23 '. Further, although not shown, a chamber may be provided so as to cover the ejection port 23 ′ so as to reduce the ejection pressure of the processing liquid.

  The present invention can be used for an electric discharge machining apparatus. Specifically, it is useful for suppressing the generation of bubbles in the express tank when the express tank is provided.

It is a right view which shows the whole structure of the electric discharge machining apparatus which concerns on 1st Embodiment of this invention. It is a systematic diagram which shows each flow path of the supply of the machining fluid of the electrical discharge machining apparatus, and rapid dispatch. It is sectional drawing which shows the internal structure of a rapid-feed tank. It is a perspective view which shows the structure of the chamber provided in the rapid-feed tank. It is sectional drawing which shows the internal structure of the chamber. It is a figure for demonstrating 2nd Embodiment of this invention. It is a perspective view for demonstrating the structure of an elastic member. It is a figure for demonstrating 3rd Embodiment of this invention.

Explanation of symbols

A: Supply pump B: Rapid flow path
W: Work 1: Electric discharge machining device 2: Bet 3: Column 4: Ram 5: Tool electrode 6: Machining head 7: Surface plate 8: Machining tank 9: Work table 10: Storage tank 20: Rapid transfer tank 21: Tank body 22 : Bottom 23: Jet 23 ': Jet 30: Chamber 31: Projection 32: Outlet 33: Bottom 34: Opening 35: Guide plate 36: Gap 37: Weir 38: Channel 40: Elastic member 40a: Storage box 41: Elastic member 50: Baffle plate 60: Baffle plate

Claims (4)

A processing tank that immerses and processes the workpiece in the processing fluid;
A storage tank for collecting and storing the processing fluid in the processing tank;
While storing the processing fluid ejected from the storage tank via a supply pump, and a rapid delivery tank for rapidly sending the stored processing fluid to the processing tank,
In an electric discharge machining apparatus comprising:
The electrical discharge machining apparatus, wherein the rapid-feed tank includes a pressure relaxation structure that relaxes the pressure of the machining liquid ejected from the storage tank. A processing tank that immerses and processes the workpiece in the processing fluid;
A storage tank for collecting and storing the processing fluid in the processing tank;
While storing the processing fluid ejected from the storage tank via a supply pump, and a rapid delivery tank for rapidly sending the stored processing fluid to the processing tank,
In an electric discharge machining apparatus comprising:
The rapid-feeding tank has an ejection port for a machining liquid ejected from the storage tank, and includes a chamber that covers the ejection port. The machining fluid ejected from the ejection port collides with the inner surface of the chamber facing the ejection port, and the collided processing fluid also collides with the inner surface of another chamber other than the inner surface. The electric discharge machining apparatus according to claim 2, wherein a guide plate is provided on the electric discharge machining apparatus. The electric discharge machining apparatus according to claim 2, wherein the ejection port is provided at a bottom portion of the express tank.

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