WO2003043770A1

WO2003043770A1 - System for treating working fluid for electric discharge machine

Info

Publication number: WO2003043770A1
Application number: PCT/JP2001/010133
Authority: WO
Inventors: Toshihiro Enya; Tsuneo Kawaguti
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2001-11-20
Filing date: 2001-11-20
Publication date: 2003-05-30
Also published as: TW529975B

Abstract

A system for treating a working fluid for an electric discharge machine, which comprises a working fluid tank (19) composed of a dirty fluid vessel (19a) and a clean fluid vessel (19b), a filtration means for an oil (38) having a filter (38a) for filtrating a dirty fluid in the dirty fluid vessel (19a) to remove working chips contained in the dirty fluid, a means (38b) for removing working chips deposited on the surface of the filter (38a) through allowing a pressurized fluid to flow from the downstream side to the upstream side of the filter (38a), a filtration means for a powder (39) having a filter (39a) for filtrating the working fluid to remove a powdery material (5) contained in the working fluid and a means for removing the powdery material (5) deposited on the surface of the filter (39a) through allowing a pressurized fluid to flow from the downstream side to the upstream side of the filter (39a). The system does not require two tanks for storing two types of working fluid, which leads to the reduction of the total tank volume for storing the working fluid and of the space for installing tanks.

Description

Description Machining fluid treatment equipment for electrical discharge machines Technical field

The present invention relates to an improvement in a machining fluid processing device of an electric discharge machine for performing electric discharge machining by switching between an oil-based machining fluid and a machining fluid in which a conductive powder material is mixed in the oil-based machining fluid. Background art

Fig. 3 is an explanatory diagram showing the outline of the configuration of a machining fluid treatment device of a conventional electric discharge machine. Machining fluid tank for storing fluid, 4a is a sewage tank of machining fluid tank 4, 4b is a clear fluid tank of machining fluid tank 4, 5 is a conductive powdery substance, 6 is conductive to oil-based machining fluid Machining fluid tank containing a machining fluid (hereinafter referred to as powder solution) containing powdered material 5 containing powders, 7 and 8 are machining waste generated by electric discharge machining, 9 is machining tank 3 to machining fluid tank 4 A valve for discharging the processing fluid from the processing tank 3 to the powder processing liquid tank 6, a valve for discharging the processing liquid from the processing tank 3, and 11 and 12 are oils from the processing liquid tank 4 to the processing tank 3. Pumps and valves for supplying system machining fluid, 13 and 14 supply powder machining fluid from powder machining fluid tank 6 to machining tank 3 Pumps and valves, 15 and 16 are pumps and filtration means for removing processing debris 7 from the waste liquid in the waste tank 4a, and 17 and 18 are when the powder material 5 has reached the end of its life. A pump and a filtering means for removing the powdery substance 5 and processing waste 8 from the powder processing liquid.

In an electric discharge machine that performs machining by switching between oil-based machining fluid and powder machining fluid Usually, oil-based machining fluid is used in roughing (hereinafter referred to as oil machining), and powder machining fluid is used in finishing machining (hereinafter referred to as powder machining).

FIG. 4 is an explanatory diagram showing a flow of processing performed using a machining fluid treatment device of a conventional electric discharge machine.

Hereinafter, the operation of the conventional machining fluid treatment apparatus of the electric discharge machine will be described along the machining flow (steps 1 to 6) shown in FIG.

① Oil processing (rough processing)

By closing valves 10 and 14 and opening valve 12 to drive pump 11, oil-based machining fluid is supplied from machining fluid tank 4b of machining fluid tank 4 to machining tank 3, and electrode 1 A voltage is applied by a power supply device (not shown) between the electrode and the workpiece 2 to perform electric discharge machining. The machining fluid containing machining waste 7 generated by the electric discharge machining is discharged from the machining tank 3 to the dirty fluid tank 4 a of the machining fluid tank 4 by opening the valve 9. The processing liquid in the waste liquid tank 4a is sent to the filtration means 16 by the pump 15 to remove the processing waste 7, and is turned into a clear liquid, sent to the clear liquid tank 4b, and then again processed by the pump 11 Supplied to 3.

(2) End of oil processing '' When the oil processing is completed, the pump 11 is stopped and the supply of the processing liquid is stopped, and the processing liquid in the processing tank 3 is discharged to the processing liquid tank 4 through the valve 9. The pump 15 is driven and the processing fluid is filtered by the filtering means 16 to remove processing debris, and sent to the cleaning liquid tank 4b as a cleaning liquid.

③ Powder processing (finish processing)

By closing the valves 9 and 12 and opening the valve 14 to drive the pump 13, the powder machining liquid is supplied to the machining tank 3, and electric discharge machining is performed in the same manner as described above. By opening the valve 10, the working fluid is discharged to the powder working fluid tank 6. (4) Confirmation of the life of the powder material and collection and supply of the powder material The amount of processing waste 8 generated by powder processing is small, and if it is a short-time powder processing, it does not affect the processing. However, after the powder processing has been performed for a long time, the amount of processing waste 8 increases and affects the processing. In addition, since the powder material 5 has a limited life when used for a certain period of time in electric discharge machining, after the powder machining has been performed for a certain period of time, the powder material 5 and the processing waste 8 in the powder machining fluid are collected and a new powder is obtained. Substance 5 needs to be supplied. The recovery of the powdery substance 5 and the processing waste 8 in the powder processing liquid is performed, for example, as follows.

That is, the powder processing time is integrated by the timer in the control means (not shown), and when the integrated time reaches the set value, the powder collection time is displayed on a display screen (not shown) to notify the worker. The operator who sees this display turns on the powder recovery switch, sends the powder processing fluid to the filtering means 18 by the pump 17, and collects the powdered substance 5 and processing waste 8 from the processing fluid. After collecting the powdered substance 5 and the processing waste 8, the operator supplies new powdered substance 5 into the working fluid. Since the conventional machining fluid treatment device of the electric discharge machine is configured as described above, two types of machining fluids, ie, an oil-based machining fluid and a powder machining fluid, are required for the capacity of the machining tank 3. In other words, two tanks, a machining fluid tank 4 and a powder machining fluid tank 6, are required, and a machining fluid having a volume approximately twice as large as that of the machining tank 3 is required, thus requiring a large installation space. There was a point. In particular, machining fluid processing equipment for large electric discharge machines has the problem that the capacity of the machining tank may exceed several thousand liters, and it requires enormous costs to secure a large amount of machining fluid and installation space. Was. Disclosure of the invention

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made in order to solve the above-mentioned problem. An object of the present invention is to provide a machining fluid treatment device for an electric discharge machine, which can reduce the capacity and installation space of a tank for storing a machining fluid in a machining fluid treatment device for an electric machining machine.

A machining fluid treatment device for an electric discharge machine according to the present invention is a machining fluid treatment device for an electric discharge machine that performs machining by switching between an oil-based machining fluid and a machining fluid in which a conductive powder material is mixed into an oil-based fluid. In the apparatus, a processing liquid tank comprising a waste liquid tank and a clear liquid tank; and an oil filtering means provided with a filter for filtering waste liquid in the waste liquid tank and removing processing waste in the waste liquid. A filtering means for powder provided with a filter for filtering the working fluid and removing the powder material in the working fluid; and flowing a pressure fluid from a downstream side to an upstream side of the filtering part of the filtering means for powder. And a powder substance removing means for removing the powder substance adhering to the filter surface of the powder filtering means.

Further, the machining fluid treatment device of the electric discharge machine according to the present invention includes a powder material disposal means for storing the powder substance removed by the powder substance removal means and collectively discarding a predetermined amount of the powder substance. .

Further, the machining fluid treatment apparatus for an electric discharge machine according to the present invention is a machining fluid for an electric discharge machine which performs machining by switching between an oil-based machining fluid and a machining fluid in which a conductive powder material is mixed into the oil-based machining fluid. A processing apparatus, comprising: a processing liquid tank including a waste liquid tank and a clear liquid tank; and a filter for oil including a filter for filtering waste liquid in the waste liquid tank and removing dust from the waste liquid. Means for removing processing debris attached to the surface of the filter of the oil filtering means by flowing a pressure fluid from a downstream side of the filter of the oil filtering means to an upstream side thereof; A filter for filtering the liquid, the filter including a filter for removing the powder material in the processing liquid, and a pressure fluid flowing from a downstream side to an upstream side of the filter of the filter for powder, Powder adhered to the filter surface of the powder filtration means It is obtained by a powder substance removing means for removing. In addition, the machining fluid treatment device of the electric discharge machine according to the present invention includes: a machining waste disposal unit configured to store machining waste removed by the machining waste removal unit and collectively discard machining waste accumulated in a certain amount; and the powder material. It is provided with at least one of powder substance disposal means for storing the powder substance removed by the removal means and collectively discarding a predetermined amount of the powder substance.

Further, in the machining fluid treatment device of the electric discharge machine according to the present invention, the powder filtering means can store the powder material removed from the filter of the powder filtering means by the powder material removing means, A supply means is provided for supplying the stored powdered substance to the working fluid in the working fluid tank.

Since the machining fluid treatment device of the electric discharge machine according to the present invention is configured as described above, the machining fluid treatment device of the electric discharge machine used for electric discharge machining by switching between an oil-based machining fluid and a powder machining fluid. In this case, since two tanks for storing the machining fluid are not required, the capacity and installation space of the tank for storing the machining fluid can be reduced. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram showing a configuration of a machining fluid treatment device for an electric discharge machine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a flow of machining performed using the machining fluid treatment device of the electric discharge machine according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an outline of the configuration of a conventional machining fluid treatment apparatus for an electric discharge machine.

FIG. 4 is an explanatory diagram showing a flow of processing performed using a machining fluid treatment device of a conventional electric discharge machine. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is an explanatory diagram showing a configuration of a machining fluid treatment apparatus of an electric discharge machine according to an embodiment of the present invention, in which 1 is an electrode, 2 is a workpiece, 3 is a machining tank, and 5 is Conductive powder material, 9 is a valve for discharging the machining fluid from machining tank 3 to machining fluid tank 19, 19a is a waste fluid tank of machining fluid tank 19, 19b is a machining fluid tank 19 clear liquid tank, 19 c is partition plate, 19 d is a window, 20 is a quick filling pump, 21 is a quick filling valve, 2 2 is a stirring valve in the processing tank, 2 3 is a constant ejection pump, 24 a and 24 b are stirring pipes,

25 is a machining fluid discharge pump, 26 is an oil discharge filter valve, 27 is a powder discharge filter valve, 28 is a filtration pump, 29 is a filter means inlet valve, 30 is a filter means outlet valve, 3 1 is an oiled waste bag valve, 3 2 is an oiled waste box,

3 2a is an oil processing waste bag, 3 3 is a powder recovery inlet valve, 3 4 is a powder recovery outlet valve, 3 5 is a powder processing waste bag valve, 3 6 is a powder processing waste box, 3 6a is a powder processing waste bag A bag, 37 is a working fluid circulation valve, 38 is an oil filtering means, 38 a is a filter made up of laminated vapor wafers, etc., 38 b is an air valve, 38 c is an oil discharge valve, 3 9 is a powder filtration means, 39 a is a filter made up of laminated paper wafers, for example, 39 b is an air valve, 39 c is a powder supply valve, 40 is a liquid cooling pump, and 41 is a processing liquid. Temperature control device, 42 is a pump for stirring in the waste liquid tank, 42 a is a pipe for stirring, 43 is a pump for stirring in the liquid tank, and 43 a is a pipe for stirring.

By opening the air valve 38b, filtration is performed by flowing compressed air from a compressed air supply source (not shown) such as a compressor, for example, from the downstream side to the upstream side of the filter 38a of the oil filtering means 38. Processing debris attached to the surface of the vessel 38a is removed. The compressed air supply source, the air valve 38b, and the like correspond to processing waste removing means having a function of removing processing waste from the filter 38a. Also, by opening the air valve 39 b By flowing compressed air from a compressed air supply source (not shown) from the downstream side to the upstream side of the filter 39 a of the filter means 39 for powder, the powder substance 5 adhered to the surface of the filter 39 a Etc. are removed. The compressed air supply source, the air valve 39b and the like correspond to a powder substance removing means having a function of removing the powder substance 5 and the like from the filter 39a.

The oil processing waste bag 32a is equivalent to a processing waste disposal means capable of storing processing waste removed from the surface of the filter 38a and collectively discarding a fixed amount of processing waste. The powder processing waste bag 36 a is equivalent to a powder material disposal means that stores the powder material 5 and the like removed from the surface of the filter 39 a and collectively discards a fixed amount of the powder material 5 and the like. The agitating pipes 24a, 24b, 42a and 43a are pipes for which several small holes have been drilled, and the machining fluid is ejected from these small holes. Is stirred. By driving the pump 42 for stirring in the waste liquid tank and the pump 43 for stirring in the clear liquid tank to eject the processing liquid from the stirring pipes 42a and 43a, the waste liquid tanks 19a and The processing liquid in the fresh liquid tank 19 b is stirred, so that processing waste and powder material can be efficiently supplied to the oil filtering means 38 and the powder filtering means 39.

Hereinafter, the operation of the machining fluid treatment apparatus of the electric discharge machine according to the embodiment of the present invention will be described along the machining flow (steps I to II) shown in FIG. ① Oil processing (rough processing)

Open the quick filling valve 21 and drive the quick filling pump 20 to supply the oil-based machining fluid to the machining tank 3 from the machining fluid tank 19. After confirming that the processing liquid is filled in the processing tank 3 by a float switch (not shown) in the processing tank 3, the quick filling pump 20 is stopped, and the quick filling valve 21 is closed. Further, the jet pump 23 is constantly driven to jet the machining fluid from the stirring pipe 24b. In this state, a voltage is applied by a power supply (not shown) between the electrode 1 and the workpiece 2 to perform electric discharge machining.

• The machining fluid containing machining waste generated by electric discharge machining is discharged from the machining tank 3 to the dirty liquid tank 19a of the machining liquid tank 19 by opening the valve 9. In addition, the filtration means inlet valve 29 and the filtration means outlet valve 30 are opened, and the filtration pump 28 is driven to filter the contaminated liquid stored in the contaminated liquid tank 19 a of the processing liquid tank 19 for oil. It is supplied to the means 38, the processing waste in the waste liquid is removed by the filter 38a, and the processing liquid which has become the cleaning liquid is sent to the cleaning liquid tank 19b.

Further, the liquid cooling pump 40 is driven, and the temperature of the liquid to be added is controlled to be substantially constant by the processing liquid temperature controller 41.

When machining dust is generated by the electric discharge machining, the machining scrap gradually adheres to the surface of the filter 38a. Therefore, for example, the oil processing time is integrated by a timer in the control means (not shown), and when the integrated time reaches the set value, the filtration pump 28 is stopped, and the filtration means inlet valve 29 and the filtration means outlet valve 30 is closed, the oil discharge valve 38c is opened, and the processing fluid in the oil filtration means 38 is discharged to the waste liquid tank 19a. After a certain period of time, the oil discharge valve 38c is closed, and the oil processing waste bag valve 31 and the air valve 38b are opened, so that the compressed air supply (not shown) moves from the downstream side to the upstream side of the filter 38a. By discharging compressed air from the source, the processing waste adhering to the surface of the filter 38a is discharged to the oil processing waste bag 32a in the oil processing waste box 32. With such a configuration, it is not necessary to replace the filter 38a due to clogging.

After a certain period of time, close the air valve 38b to stop the supply of compressed air from the compressed air supply source.Then, the filter means inlet valve 29, the filter means outlet valve 30 and the oil processing waste bag valve 31 And return the filtration pump 28 Then, the filtration of the working fluid by the oil filtering means 38 is started again.

② Finished oil processing

When the oil processing is completed, the jet pump 23 is always stopped and the valve 9 is closed. The driving of the filtration pump 28 for a certain period of time is continued, and the waste liquid stored in the waste liquid tank 19 a of the machining liquid tank 19 is supplied to the oil filtration means 38 to be filtered.

8a removes processing waste from the waste liquid, and removes the processing liquid that has been

Send to 9 b. The partition 19c is formed with a window 19d that opens only in the direction of arrow A in the figure due to the pressure difference, and the working fluid in the clean liquid tank 19b flows into the dirty liquid tank 19a, causing The processing liquid in the liquid tank 19a also becomes a clear liquid.

Next, since the processing fluid stored in the processing tank 3 contains processing waste generated by the processing, the processing waste is removed. That is, the processing pump stored in the processing tank 3 is stopped by stopping the filtration pump 28, closing the filtration means inlet valve 29, driving the processing liquid discharge pump 25, and opening the oil discharge filtration valve 26. Is sent to the oil filtration means 38, the processing waste in the waste liquid is removed by the filter 38a, and sent to the fresh liquid tank 19b as a fresh liquid.

③ Check if there is any powdery substance in the powder filtration means

After the oil processing is completed, powder processing is performed. Before powder processing, first, it is checked whether or not the powdered substance 5 is stored in the powder filtering means 39. If the powder material 5 is discarded in the process (2), for example, "Powder substance replenishment" is displayed on the screen display of the not-shown display means. If there is an indication of "replenishment", it is determined that the powdered substance 5 is not stored in the powder filtration means 39. Judge that 5 is stored.

If powdered substance 5 is stored in the powder filtration means 3 9, the process ④— 1 When the powdered substance 5 is not stored in the powder filtration means 39, the powdered substance 5 is supplied manually or automatically, and then the step II-2 is performed.粉末 Powder substance supply by powder substance removal means

④— 1

When the powdered substance 5 is stored in the powder filtration means 39, the air valve 39b and the powder supply valve 39c are opened, and the powder recovery outlet valve 34 and the powder processing waste bag valve 35 are closed. Thereafter, by flowing compressed air from a compressed air supply source (not shown) from the downstream side of the filter 39a to the upstream side of the filter 39a from the air valve 39b, the powdered substance 5 adhering to the surface of the filter 39a is removed. Then, the powdered substance 5 is supplied from the powder supply valve 39c to the fresh liquid tank 19b, so that the powdered substance 5 can be reused. The powder supply valve 39 c corresponds to a supply means for supplying the powdered substance 5 to the processing liquid in the cleaning liquid tank 19 b of the processing liquid tank 19.

④— 2

Close the filtration means inlet valve 29, open the machining fluid circulation valve 37, drive the filtration pump 28, and send the machining fluid from the dirty fluid tank 19a to the clear liquid tank 19b. The working fluid circulates inside the working fluid tank 19 through the window 19 d that opens only in the direction of arrow A in the figure due to the pressure difference, so that the powdered material can be efficiently mixed into the working fluid.

⑤Powder processing (finish processing)

After the powdered substance 5 is supplied as described above and the powdered substance 5 is mixed in the entire processing liquid, the quick filling valve 21 is opened, and the rapid filling pump 20 is operated, whereby powder processing is performed on the processing tank 3. Supply liquid.

After that, close the rapid filling valve 21 and open the agitation valve 22 inside the processing tank, always drive the jet pump 23, and the processing liquid is jetted from the stirring pipes 24a and 24b, and the processing tank 3 Are agitated, and electric discharge machining is performed in the same manner as described above. It is. In addition, the discharge valve 9 is opened to discharge the processing liquid in the processing tank 3 to the processing liquid tank 19. In the machining fluid treatment device of the electric discharge machine according to the embodiment of the present invention, the machining fluid circulates as in step II.

終了 Finished powder processing

After powder processing, remove powder material 5 and processing waste in the processing fluid in preparation for the next oil processing. That is, by closing the tank circulation valve 37 and opening the powder recovery inlet valve 33 and the powder recovery outlet valve 34, the powder processing liquid in the processing tank 19 is sent to the powder filtering means 39, and the 39 Remove powdered substance 5 and processing waste by 9a. After a lapse of a predetermined time, the powder collection inlet valve 33 is closed, the filtration pump 28 is stopped, the powder discharge filtration valve 27 is opened, and the processing fluid discharge pump 25 is driven to drive the powder in the processing tank 3. The processing liquid is sent to the powder filtration means 39, and the powder substance 5 and dust are removed by the filter 39a.

確認 Confirmation of expiration of powder material and disposal of powder material

As described above, due to the life of the powdered substance 5, it is necessary to collect the powdered substance 5 and processing waste in the powder processing liquid after supplying the powder for a certain period of time and supply a new powdered substance 5.

For example, the powder processing time is integrated by a timer in the control means (not shown), and the operator confirms that the integrated time has reached the set value on the screen display of the display means (not shown). If the accumulated time has reached the set value, the powdered substance 5 and the like are discarded as follows, and if the accumulated time has not reached the set value, the step (2) is performed.

First, open the air valve 39 b and powder processing waste bag valve 35 and close the powder recovery outlet valve 34. After that, compressed air from a compressed air supply source (not shown) is flowed from the downstream side to the upstream side of the filter 39a through the air valve 39b, so that the powder substance adhering to the surface of the filter 39a is 5 and add The dust material and the powdered substance 5 inside the filtering means 39 for powder and the processing waste are blown off by the pressure of the compressed air to the powder processing waste bag 36 a in the powder processing waste box 36.

The worker can dispose of the powdered substance 5 and the like collected in the powder processing waste bag 36 a together with the bag, so that the work of disposing of the powdered substance 5 and the like can be performed easily. Further, such a configuration makes it unnecessary to replace the filter 39a due to clogging.

When the operator disposes of the powdered substance 5 or the like, the operator presses a switch, for example, “discarded powdered substance”, and a display, for example, “refilled powdered substance” is displayed on display means (not shown).

⑧Powder substance storage

If the accumulated time of the powder processing time by the timer in the control means has not reached the set value, the powdered substance 5 is stored together with the processing fluid in the powder filtration means 39 until it is used again.

In the above description, the case where the processing debris is removed by the processing debris removing means using compressed air to remove the processing debris adhering to the surface of the filter 38a is described. Similarly, in the powder substance removing means, the case of removing the powder substance 5 attached to the surface of the filter 39 a with compressed air has been described. Or a liquid such as a working fluid. In the electric discharge machining performed by switching between an oil-based machining fluid and a powder machining fluid, a prototype of the machining fluid treatment device of the electric discharge machine according to the embodiment of the present invention is used. It has been confirmed that the volume of machining fluid in the machining fluid tank is approximately 1/2 and the installation space for the machining fluid tank is also approximately 1/2 compared to the equipment. Industrial applicability

As described above, the machining fluid treatment apparatus for an electric discharge machine according to the present invention is suitable for being used for electric discharge machining performed by switching between an oil-based machining fluid and a powder machining fluid.

Claims

The scope of the claims

1. In a machining fluid treatment device of an electric discharge machine that performs machining by switching between an oil-based machining fluid and a coolant mixed with a powdered material having conductivity in the oil-based machining fluid, a waste liquid tank and a clear liquid tank are used. Processing fluid tank,

An oil filtering means having a filter for filtering the waste liquid in the waste liquid tank and removing processing waste in the waste liquid;

A filtering means for powder, comprising: a filter for filtering the working fluid and removing the powder material in the working fluid;

Powder material removing means for removing the powder material attached to the surface of the filter of the powder filtering means by flowing a pressure fluid from the downstream side to the upstream side of the filter of the powder filtering means. Features EDM machining fluid treatment equipment.

2. The machining fluid for an electric discharge machine according to claim 1, further comprising a powder material disposal means for storing the powder material removed by the powder material removing means and collectively discarding a fixed amount of the powder material. Processing equipment.

3. In a machining fluid treatment device of an electric discharge machine that performs machining by switching between an oil-based machining fluid and a coolant mixed with a conductive powder substance in the oil-based machining fluid, the waste fluid tank and the cleansing fluid tank are separated. Processing fluid tank,

An oil filtering means comprising a filter for filtering the waste liquid in the waste liquid tank and removing processing waste in the waste liquid,

A processing waste removal unit that removes processing waste attached to the surface of the filtration unit of the oil filtration unit by flowing a pressure fluid from a downstream side of the filtration unit of the oil filtration unit to an upstream side of the filtration unit. A filtering means for powder, comprising: a filter for filtering the working fluid and removing the powder material in the working fluid;

4. The processing waste discarding means according to claim 3, wherein the processing waste removed by the processing waste removing means is stored, and the processing waste accumulated in a certain amount is collectively disposed of, and the powder material removed by the powder material removing means. A machining fluid treatment apparatus for an electric discharge machine, comprising: at least one of powder substance disposal means for storing a predetermined amount of powdered substance and collectively discarding the powdered substance.

5. The powder filtering device according to any one of claims 1 to 4, wherein the powder filtering device can store the powder material removed from the filter of the powder filtering device by the powder material removing device, and the stored powder material. A supply means for supplying the machining fluid to the machining fluid in the machining fluid tank.

The processing liquid tank (19) consisting of a waste liquid tank (19a) and a clean liquid tank (19b) and the waste liquid in the waste liquid tank (19a) are filtered to remove processing waste in the waste liquid. A filtering means for oil (38) equipped with a filter (38a), and a pressure fluid flowing from the downstream side to the upstream side of the filter (38a) to remove processing waste adhering to the surface of the filter (38a). A powder removing means (39) provided with a swarf removing means (38b) for removing, a filter (39a) for filtering the working fluid and removing a powdery substance (5) in the working fluid, A powder substance removing means for removing the powder substance (5) attached to the surface of the filter (39a) by flowing a pressure fluid from a downstream side to an upstream side of the filter (39a). Since two tanks for storing the processing fluid are not required, the capacity and installation space of the tank for storing the processing fluid can be reduced.