JP2004142098A - Electric discharge machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric discharge machining device in which fine powder is hardly deposited in a T-slot during the machining, the fine powder is easily washed away after the machining or when exchanging machining liquid, and the working time is shortened. <P>SOLUTION: In the electric discharge machining device in which the machining liquid with conductive fine powder mixed therein and the machining liquid without fine powder mixed therein are stored in storage tanks, each machining liquid is fed between an electrode and a work according to the machining state, the work is machined thereby, and the machining liquid is collected in the storage tank, pipes to connect the storage tanks 6 and 13 to a machining tank 1 and to feed the machining liquid to the machining tank 1 are commonly used in the middle and merged with each other. A merging part is located at a highest part, and a gas feed means 41 to feed gas to the merging part is provided. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an electric discharge machining apparatus and a machining method for machining a workpiece with a machining fluid mixed with conductive fine powder, and more particularly to an improvement in a machining fluid system.

FIG. 8 is a block diagram showing a conventional electric discharge machining apparatus. In the figure, 1 is a machining tank, 1a is a partition plate for overflowing a machining fluid, 2 is a surface plate for setting a work (not shown), 3 is machining. The liquid, 3a is a machining liquid overflowing from the partition plate 1a, 4 is a drainage shutter, 5 is a valve for controlling the discharge of the oil processing liquid, 6 is a storage tank for storing the oil processing liquid, and 7 is a supply of the oil processing liquid. Pump 8, a valve for controlling the supply of oil working fluid, 9 a working fluid temperature controller (hereinafter referred to as a cooler), 10 a tank for exchanging heat in the cooler 9, 11 a working fluid supply pipe, and 12 a working fluid supply pipe A valve for controlling the discharge of the powder processing liquid, 13 is a storage tank (hereinafter referred to as a powder tank) for storing a processing liquid mixed with a so-called conductive fine powder of metal or semiconductor, preferably silicon, and 14 is a powder tank. Working solution 攪 solder jetting pipes click 13, 15 pump for supplying the powder processing fluid, 16 is a valve for controlling the supply of powder processing fluid.

Next, the operation will be described. The work is set on the surface plate 2 and the processing liquid 3 is supplied into the processing tank 1. The oil processing liquid is supplied to the processing tank 1 through an oil tank 6, an oil supply pump 7, an oil processing liquid supply valve 8, a cooler 9, and a processing liquid supply pipe 11. The processing liquid 3 a that overflows the partition plate 1 a for setting the liquid level in the processing tank 1 is returned to the oil storage tank 6 through the oil discharge valve 5. When discharging the processing liquid 3 in the processing tank 1, the discharge shutter 4 is opened. When the working fluid passes through the heat exchange tank 10 in the cooler 9, heat is transferred to and from a coolant (not shown) to control the temperature. The powder processing liquid is supplied to the processing tank 1 through the powder tank 13, the powder supply pump 15, the powder processing liquid supply valve 16, the cooler 9, and the processing liquid supply pipe 11, and is discharged from the overflowed powder processing liquid 3a or the discharge shutter 4. The working fluid 3 is discharged to a powder tank 13 through a powder discharge valve 12. Since the specific gravity of the fine powder is generally larger than that of the processing liquid, the liquid pressurized by the powder supply pump 15 or the stirring pump (not shown) is jetted from the stirring pipe 14 into the powder tank 13, To prevent precipitation.

In the electric discharge machining apparatus configured as described above, first, rough and medium machining is performed with an oil machining fluid, and then the machining is switched to a powder machining fluid to perform finish machining. When the processing liquid is switched, the processing tank is cleaned and the supply valves 8 and 16 and the discharge valves 5 and 12 are controlled. In rough / medium machining, an oil machining fluid is used at a high speed to suppress the consumption of electrodes (not shown). In the finishing processing, a powder processing liquid is used to make the surface roughness fine. When the fine powder is mixed into the working fluid, the discharge is not concentrated, so that the working surface is not roughened. Thus, it is very effective to perform the electric discharge machining by switching the machining fluid.
FIG. 9 shows a work placement example in which a work is set on the surface plate 2 of a conventional electric discharge machining apparatus. Reference numeral 20 denotes a work, 21 denotes fine powder precipitated during processing, and 22 denotes a T slot.

(4) Since the conventional electric discharge machining apparatus is configured as described above, there is a problem that the powder precipitates in the powder tank 13 where the injection liquid from the injection pipe 14 does not reach. Further, there is a problem that the fine powder adheres to the side surface of the powder tank.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In a powder tank, a uniform processing liquid is stored in the entire powder tank without causing the powder to settle or adhere to the side of the powder tank. It is to obtain an electric discharge machine.

An electric discharge machining apparatus according to the present invention supplies a machining fluid mixed with conductive fine powder between an electrode and a work, and stores the machining fluid mixed with the fine powder in the electric discharge machining apparatus for machining the work. The storage tank is configured such that the lower part of the storage tank has a smaller sectional area than the upper part.

Further, a suction port of a pump for supplying a processing liquid to a processing tank is arranged at the bottom of the tank.

In addition, the storage tank is configured such that a lower portion has a gradually decreasing cross-sectional area with respect to an upper portion, and a slope is formed on a bottom surface or a side surface, and a machining fluid that sprays a machining fluid along the slope is provided. It is provided with an injection means.

As described above, according to the present invention, the working fluid mixed with the conductive fine powder and the working fluid not mixed with the fine powder are stored in the respective storage tanks, and the respective working fluids are processed in the processing state. In an electric discharge machining apparatus that switches between the electrodes and supplies the workpiece between the electrode and the workpiece, processes the workpiece, and collects the machining fluid in the respective storage tanks, the machining fluid is stored in the machining fluid mixed with the fine powder. The tank is configured such that its cross-sectional area is gradually reduced at the lower part with respect to the upper part, and the suction port of a pump for supplying a processing liquid to the processing tank is arranged at the bottom of the tank, so that the settling of fine powder is reduced. There is an effect that the working fluid in which the fine powder is dispersed uniformly can be always collected uniformly without waste.

In addition, the machining liquid storage tank is configured such that a lower portion has a gradually decreasing cross-sectional area with respect to an upper portion, and an inclined surface is formed on a bottom surface or a side surface, and a machining liquid is sprayed along the inclined surface. The provision of the working fluid jetting means has an effect of collecting the fine powder sediment more efficiently at one place.

The electric discharge machining apparatus and the machining method according to the present invention are configured such that the machining fluid storage tank for storing the machining fluid mixed with the fine powder is such that the lower part thereof is gradually reduced in cross-sectional area with respect to the upper part. The fine powder precipitate is collected in approximately one place.

Further, the machining fluid storing tank for storing the machining fluid mixed with the fine powder is provided with the machining fluid ejecting means for ejecting the machining fluid along the inclined surface, thereby removing the fine powder attached to the side surface of the powder tank. .

Embodiment 1 FIG.
FIG. 1 and FIG. 2 are configuration diagrams relating to liquid level control and discharge of a machining fluid in a machining tank of an electric discharge machine according to a first embodiment of the present invention. 1 and 2, reference numerals 30 and 31 denote lids, reference numerals 32 and 33 denote processing fluid discharge pipes, reference numeral 34 denotes a processing tank provided directly with a connection port to the processing liquid discharge pipes 32 and 33, and reference numeral 35 denotes a set. A float switch serving as a liquid level detecting means for detecting a liquid level, 36 is an O-ring for preventing leakage of machining fluid when the lids 30 and 31 are closed, and 37 is a drive unit (for example, for opening and closing the lids 30 and 31) An air cylinder is shown), and the cover 30 and the drive unit 37 constitute a working fluid discharge unit. The lid 31 has the same configuration. Numeral 38 denotes a control means for controlling the opening and closing of the processing fluid discharge means by detecting the liquid level by the float switch 35 or at the time of discharging the processing fluid. 3 to 5 show a method for controlling the opening and closing of the lids 30 and 31. FIG.

放電 The electric discharge machining apparatus according to this embodiment requires two discharge systems to switch between two machining fluids, an oil machining fluid and a powder machining fluid. In the method of switching by a discharge valve as in the conventional example, there is a problem that the discharge time is prolonged due to a small processing liquid discharge capability of the discharge valve, and the fine powder precipitates during the discharge. Further, shortening the discharge time leads to an increase in the size of the discharge valve, which causes problems such as deformation of a table (not shown) that defines the position of the surface plate 2 and interference during stroke movement. Further, there is a problem that the pipes from the processing tank to the discharge valve mix with each other because the two processing liquids pass through. In this embodiment, the structure of the machining fluid discharge system is simplified by eliminating the partition plate 1a for setting the fluid level, the discharge shutter 4 and the like, the piping through which the two machining fluids pass is minimized, and the discharge flow rate is easily increased. can do. Therefore, the adhesion, sedimentation, and outflow of the fine powder can be reduced. The working fluid discharge pipes 32 and 33 are connected to the oil tank 6 or the powder tank 13. When the processing tank 34 is filled with the oil processing liquid, the lid 31 is opened and discharged, and when the processing tank 34 is filled with the powder processing liquid, the lid 30 is opened and discharged. The lids 30 and 31 are controlled to open and close by a drive unit 37, for example, an air cylinder. With the above configuration, the portion common to the two processing fluids is reduced to only the processing tank as much as possible, so that the outflow of the powder is reduced, and the flow rate of the processing fluid discharge depends only on the diameter of the processing fluid discharge pipes 32, 33. Therefore, the discharge amount of the working fluid can be easily increased.

Next, FIGS. 3 to 5 show a control method for opening and closing the lids 30 and 31 for eliminating the partition plate 1a for setting the liquid level, the discharge shutter 4, and the like. After the processing tank 1 is filled with the processing liquid to a predetermined height, a fresh processing liquid (for example, an oil processing liquid from which processing powder is removed) is continuously supplied. The same amount of the processing liquid as the supplied processing liquid is discharged from the processing tank 34, and the processing liquid circulates. When the float switch 35 detects the filling of the working fluid and inputs it to the control means 38, the control means 38 sends a drive signal of the air cylinder 37 to open and close the lids 30 and 31 in the sequence of FIGS. Output. In FIG. 3, the lids 30 and 31 are opened at a small angle θ (θ is shown in FIG. 1) corresponding to the balance between the supply amount and the discharge amount in order to keep the working fluid level after the working fluid is full. At the time of discharge for switching of the processing liquid or the like, the lids 30 and 31 are made large, for example, 90 degrees apart. In FIG. 4, the working fluid is discharged in the same manner as in FIG. 3 by periodically opening the lids 30 and 31 for a short time. In FIG. 5, the lids 30 and 31 are opened when the float switch 35 for setting the liquid level detects the liquid level and is ON, and when the float 35 is OFF without detecting the liquid level, the lids 30 and 31 are opened. Close. By these control methods, the partition plate 1a and the discharge shutter 4 and the like can be omitted to obtain a compact and simple processing tank and discharge of the processing liquid in a short time. Adhesion and precipitation are reduced.

Embodiment 2 FIG.
FIG. 6 is a configuration diagram showing an electric discharge machining apparatus according to Embodiment 2 of the present invention. In FIG. 6, 1 is a processing tank, 6 is an oil tank 6, 8 is an oil processing liquid supply valve, 9 is a cooler, 13 is a powder tank, 16 is a powder processing liquid supply valve, 40 is an inflow side and an outflow side. Reference numeral 41 denotes a heat exchange tank disposed below, a valve 41 for controlling the supply of air serving as a gas supply means, and 42 a processing liquid supply pipe.

(4) If a common pipe is used to pass the oil machining fluid and the powder machining fluid as in the conventional electric discharge machining apparatus, there is a problem that the machining fluids are mixed. In particular, when switching from the powder processing liquid to the oil processing liquid, there is a problem that the fine powder in the common pipe flows out to the oil processing liquid. In the electric discharge machining apparatus of this embodiment, the cooler 9 and the following are common pipes, and are arranged so that the valve 41, the heat exchange tank 40, and the machining fluid supply pipe 42 become lower in this order. When switching the processing liquid, the valve 41 is opened and air is pushed in, and the processing liquid in the heat exchange tank 40 and the processing liquid pipe 42 flows into the processing tank 1 and finally discharged to each tank. At this time, it is more effective to close the oil processing liquid supply valve 8 and the powder processing liquid supply valve 16. Although the gas used has been described as an example of air, it goes without saying that the same effect can be obtained by using H2 gas or other gases.

Embodiment 3 FIG.
FIG. 7 is a configuration diagram showing a powder tank of an electric discharge machine according to Embodiment 3 of the present invention. In FIG. 7, reference numeral 50 denotes a powder tank having an inclined bottom surface or side surface, and reference numerals 51, 52, and 53 designate nozzles serving as machining fluid ejecting means for ejecting machining fluid along the inclined surface.

Fine powder precipitates because it has a higher specific gravity than the working fluid. Conventionally, a working fluid has been sprayed from a stirring pipe so as not to precipitate. However, there is a problem that the fine powder precipitates where the jetting liquid does not reach. Conventionally, a stirring pipe was provided on the bottom surface of a rectangular parallelepiped powder tank. However, for example, sedimentation points were dispersed at four corners and the like, and there was a problem that stirring was difficult. Therefore, it is an object of the present invention to construct a tank structure in which sedimentation places are collected in one place. In FIG. 7, the bottom and side surfaces of the powder tank 50 are inclined such that the suction port of the powder supply pump 15 is the deepest, and the lower part is narrowed with respect to the upper part. As a result, the sediment of the fine powder collects at the suction port of the powder supply pump 15, so that when the pump rotates, the sedimented fine powder is sucked. Fine powder which does not float in the processing liquid as precipitated as in the prior art can be greatly reduced. The structure in which the lower part of the powder tank 50 is narrowed to the upper part is not limited to the above-described linear shape.

加工 By spraying the machining liquid along the inclined surface, the effect of collecting the fine powder in one place can be further enhanced. The injection nozzles 51, 52 and 53 inject liquid from the powder supply pump 15 or a stirring pump (not shown).

1 is a configuration diagram illustrating an electric discharge machine according to a first embodiment of the present invention. FIG. 2 is a detailed view showing a configuration of a liquid level control in a machining tank and a machining fluid discharge means of the electric discharge machining apparatus of FIG. 1. FIG. 2 is a diagram showing a control method for opening and closing a lid of the electric discharge machine according to the first embodiment of the present invention. FIG. 3 is a diagram showing another control method of opening and closing the lid of the electric discharge machine according to the first embodiment of the present invention. FIG. 5 is a view showing still another control method for opening and closing the lid of the electric discharge machine according to the first embodiment of the present invention. FIG. 4 is a configuration diagram illustrating an electric discharge machine according to a second embodiment of the present invention. FIG. 9 is a view showing a powder tank of an electric discharge machine according to Embodiment 3 of the present invention. It is a block diagram which shows the conventional electric discharge machine. It is an example of mounting a work on a surface plate of a conventional electric discharge machine.

Explanation of reference numerals

6 Oil storage tank (oil tank), 13 oil storage tank containing fine powder (powder tank), 20 work, 22 T slot, 30 lid, 31 lid, 32 pipe for draining fluid, 33 oil processing Liquid drainage pipe, 34 ° processing tank, 35 ° float switch (liquid level detecting means), 37 ° drive unit, 38 ° control means, 41 ° valve for controlling air supply (gas supply means), 50 ° bottom or side inclined. Powder tank, 51 ° nozzle (working fluid spraying means), 52 ° nozzle (working fluid spraying means), 53 ° nozzle (working fluid spraying means).

Claims (6)

The working fluid mixed with the fine powder having conductivity and the working fluid not mixed with the fine powder are stored in a storage tank, and each of the working fluids is switched according to the processing situation and supplied between the electrode and the workpiece. An electric discharge machining apparatus for machining a workpiece and collecting a machining fluid in the storage tank, wherein a T slot having a bottom surface inclined is provided on a surface plate on which the workpiece is mounted. The working fluid mixed with the fine powder having conductivity and the working fluid not mixed with the fine powder are stored in a storage tank, and each of the working fluids is switched according to the processing situation and supplied between the electrode and the workpiece. In a discharge machining apparatus that processes a work and collects a machining fluid in the storage tank, a fluid level detection unit that detects a fluid level of the machining fluid in the machining tank, and each of the individual fluids that individually discharges the machining fluid. A processing fluid discharge means having a discharge capacity corresponding to a discharge capacity of a processing fluid discharge pipe, and detecting a predetermined liquid level by the liquid level detection means, the processing liquid discharge means is provided. An electric discharge machining apparatus comprising: a control unit that opens and closes and controls a discharge amount of the machining fluid. The working fluid mixed with the fine powder having conductivity and the working fluid not mixed with the fine powder are stored in a storage tank, and each of the working fluids is switched according to the processing situation and supplied between the electrode and the workpiece. In the electric discharge machining method for processing a work and collecting the working fluid in the storage tank, when the working fluid in the working tank reaches a predetermined amount, the liquid level is detected and the working fluid per time supplied to the working tank is detected. The amount of machining fluid discharged per time is determined in accordance with the amount of the fluid, and the liquid level is controlled to a constant level.When the machining fluid is collected in the storage tank, the collection of the machining fluid is completed in a predetermined draining time. An electric discharge machining method characterized in that a discharge amount per hour of the machining fluid is determined. The working fluid mixed with the fine powder having conductivity and the working fluid not mixed with the fine powder are stored in a storage tank, and each of the working fluids is switched according to the processing situation and supplied between the electrode and the workpiece. In the electric discharge machine for processing the work and collecting the working fluid in the storage tank, a pipe for connecting the storage tank and the working tank and supplying the working fluid to the working tank is shared in the middle and merged, An electric discharge machining apparatus comprising: a gas supply means for arranging the junction at the top and supplying gas to the junction. The working fluid mixed with the fine powder having conductivity and the working fluid not mixed with the fine powder are stored in a storage tank, and each of the working fluids is switched according to the processing situation and supplied between the electrode and the workpiece. In a discharge machining apparatus that processes a workpiece and collects a machining fluid in the storage tank, a machining fluid storage tank that stores a machining fluid mixed with the fine powder has a lower portion gradually increasing in cross-sectional area with respect to an upper portion. An electric discharge machine, wherein the suction port of a pump for supplying a machining liquid to a machining tank is arranged at the bottom of the tank. 6. A machining fluid ejecting means for ejecting machining fluid along an inclined surface in the direction of the tank bottom on a top surface of a machining fluid storage tank for storing a machining fluid mixed with fine powder. EDM equipment.

Images