Electric discharge machining machine and electric discharge machining method

Abstract

To provide a wire electric discharge machine that can extend a service life of a filter 32, even when subjecting an aluminum-based material to electric discharge machining.SOLUTION: A wire electric discharge machine (10) according to an embodiment in the disclosure subjects an aluminum-based material to electric discharge machining. A processing liquid used for electric discharge machining in the wire electric discharge machine includes one or more cations selected from potassium ions, calcium ions, sodium ions, and magnesium ions, and one or more anions selected from sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electric discharge machine and an electric discharge machining method. [Background technology]

[0002] WO 2006 / 126248 discloses an electric discharge machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2006 / 126248 Summary of the Invention

[0004] Recently, there has been a demand for better electrical discharge machines.

[0005] An aspect of the present disclosure is an electric discharge machine for electric discharge machining of an aluminum-based material, in which the machining fluid used during electric discharge machining in the electric discharge machine contains one or more cations selected from potassium ions, calcium ions, sodium ions, and magnesium ions, and one or more anions selected from sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a wire electric discharge machine. DETAILED DESCRIPTION OF THE INVENTION

[0007] Electrical discharge machines filter the machining fluid used in machining. Filtration removes sludge and other contaminants from the machining fluid, which then adhere to the filter. Electrical discharge machines reuse the filtered machining fluid. When the pressure required for the machining fluid to pass through the filter exceeds a predetermined value, the operator must replace the filter. Therefore, electrical discharge machines are required to have long filter lifespans. The filter lifespan refers to the period from when the filter is replaced with a new one until the pressure required for the machining fluid to pass through the filter exceeds a predetermined value.

[0008] The filter lifespan when the electric discharge machine processes aluminum-based materials is shorter than the filter lifespan when the electric discharge machine processes iron-based materials. For example, when a wire electric discharge machine processes iron and aluminum materials of the same thickness, the filter lifespan when processing the aluminum material is 10% to 25% of the filter lifespan when processing the iron material.

[0009] Therefore, when an aluminum-based material is machined using an electric discharge machine, there is a problem that the amount of filter waste increases. An object of the present disclosure is to extend the life of the filter.

[0010] [First embodiment] [Wire EDM Machine Configuration] 1 is a schematic diagram of a wire electric discharge machine 10. The wire electric discharge machine 10 has a machine body 12, a machining fluid treatment device 14, and a numerical control device 16. The wire electric discharge machine 10 corresponds to the electric discharge machine of the present invention.

[0011] The processing machine body 12 has a processing tank 18. The processing machine body 12 performs electrical discharge machining of a workpiece with processing fluid stored in the processing tank 18.

[0012] The machining fluid treatment device 14 includes a wastewater tank 20, a clean water tank 22, and an ion exchange unit 24.

[0013] The wastewater tank 20 is connected to the machining tank 18 via a drainage path 26. Machining fluid is discharged from the machining tank 18 into the wastewater tank 20. The machining fluid discharged from the machining tank 18 to the wastewater tank 20 contains sludge and the like generated during the electrical discharge machining of the workpiece.

[0014] The wastewater tank 20 is connected to the clean water tank 22 via a filtration path 28. A first pump 30 and a filter 32 are provided in the filtration path 28. The first pump 30 sucks up the machining fluid from the wastewater tank 20 and sends it to the clean water tank 22. The filter 32 filters the machining fluid sent from the wastewater tank 20 to the clean water tank 22, removing sludge and the like from the machining fluid.

[0015] The fresh water tank 22 is connected to the ion exchange unit 24 via a circulation path 34. A second pump 36 and a valve 38 are provided in the circulation path 34. The ion exchange unit 24 has an ion exchange resin therein. The second pump 36 circulates the machining fluid between the fresh water tank 22 and the ion exchange unit 24. The ion exchange resin exchanges ions contained in the machining fluid passing through the ion exchange resin with other ions. This increases the resistivity of the machining fluid.

[0016] The machining tank 18 is connected to the clean water tank 22 by a water supply path 39. The machining tank 18 is supplied with machining fluid whose resistivity has been adjusted.

[0017] The valve 38 adjusts the amount of machining fluid circulating between the clean water tank 22 and the ion exchange section 24 .

[0018] The numerical control device 16 controls the machining machine body 12. The numerical control device 16 also controls the opening degree or opening time of the valve 38 in accordance with the resistivity of the machining fluid measured by the resistivity measurement unit 40. The resistivity measurement unit 40 measures the resistivity of the machining fluid stored in the clean water tank 22. This allows the resistivity of the machining fluid in the clean water tank 22 to be maintained at a predetermined value.

[0019] [Ions contained in machining fluid] The machining fluid used in the wire electric discharge machine 10 of the present disclosure contains one or more types of cations among the following: potassium ions, calcium ions, sodium ions, and magnesium ions.

[0020] Furthermore, the machining fluid used in the wire electric discharge machine 10 of the present disclosure contains one or more of the following anions: sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions.

[0021] Of the above ions, the following ions are contained in the machining fluid by adding chemicals to the machining fluid: potassium ions, calcium ions, sodium ions, magnesium ions, sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions.

[0022] The chemicals that are added include, for example, the following chemicals: sodium bisulfite, sodium carbonate, sodium sulfate, calcium hydroxide, sodium disulfite (sodium pyrosulfite), potassium disulfite (potassium pyrosulfite), magnesium sulfate, magnesium sulfate heptahydrate, etc.

[0023] Of the above ions, sodium ions and hydroxide ions are contained in the machining fluid by passing the machining fluid through the ion exchange resin of the ion exchange section 24 .

[0024] Ion exchange resins having carboxyl groups or sulfonic acid groups as exchange groups may be used as cation exchange resins in the ion exchange unit 24. Ion exchange resins having amino groups introduced as functional groups may be used as anion exchange resins in the ion exchange unit 24.

[0025] When a workpiece made of an aluminum-based material is subjected to electrical discharge machining using the wire electrical discharge machine 10 of the present disclosure, aluminum oxide and aluminum oxide trihydrate are produced.

[0026] In the wire electric discharge machine 10, the machining fluid after machining contains copper ions, zinc ions, hydrogen ions, and hydroxide ions. In the wire electric discharge machine 10 of the present disclosure, the copper ions, zinc ions, hydrogen ions, and hydroxide ions are not removed.

[0027] [About the experimental results] The inventors of the present application conducted an experiment to determine the life of the filter 32 by performing electrical discharge machining using a plurality of types of machining fluids containing different ions.

[0028] It has been confirmed that the life of the filter 32 is extended when the machining fluid contains one of the following ions: potassium ions, calcium ions, sodium ions, magnesium ions, hydrogen ions, sulfate ions, sulfite ions, hydrogen sulfite ions, and hydroxide ions.

[0029] On the other hand, it was not confirmed that the life of the filter 32 was extended when the machining fluid contained chloride ions.

[0030] Furthermore, it was not confirmed that the life of the filter 32 was extended when the machining fluid contained both hydrogen ions and hydroxide ions.

[0031] When sodium bisulfite is added to the machining fluid, aluminum oxide and aluminum oxide trihydrate are produced in the machining fluid during electrical discharge machining of an aluminum-based material. On the other hand, when sodium bisulfite is not added to the machining fluid, aluminum hydroxide is produced in the machining fluid during electrical discharge machining of an aluminum-based material. It is believed that adding sodium bisulfite to the machining fluid produces aluminum oxide and aluminum oxide trihydrate instead of aluminum hydroxide, which shortens the life of the filter 32.

[0032] [Action and effect] When aluminum-based materials are machined using the wire electric discharge machine 10, aluminum hydroxide is generated in the conventional machining fluid. The surface of aluminum hydroxide is sticky. Therefore, aluminum hydroxide easily clogs the meshes of the filter 32, shortening the life of the filter 32. If the life of the filter 32 is shortened, there is a problem that the amount of filter 32 to be discarded increases. Therefore, the wire electric discharge machine 10 is required to have a long life of the filter 32, even when electric discharge machining aluminum-based materials.

[0033] In the wire electric discharge machine 10 of this embodiment, the machining fluid used during electric discharge machining contains one or more of the following cations: potassium ions, calcium ions, sodium ions, and magnesium ions. Furthermore, the machining fluid used during electric discharge machining contains one or more of the following anions: sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions. This enables the wire electric discharge machine 10 to extend the life of the filter 32.

[0034] Furthermore, in the wire electric discharge machine 10 of this embodiment, the following ions are contained in the machining fluid by adding a chemical to the machining fluid: potassium ions, calcium ions, sodium ions, magnesium ions, sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions. This allows these ions to be contained in the machining fluid using a simple method.

[0035] In the wire electric discharge machine 10 of this embodiment, the following ions are contained in the machining fluid by passing the machining fluid through an ion exchange resin. These ions are sodium ions and hydroxide ions. This allows these ions to be contained in the machining fluid in a simple manner.

[0036] Furthermore, the wire electric discharge machine 10 of this embodiment generates aluminum oxide and aluminum oxide trihydrate by electric discharge machining an aluminum-based material, thereby extending the life of the filter 32.

[0037] The following additional notes are further disclosed regarding the above embodiment.

[0038] (Appendix 1) In an electric discharge machine (10) for electric discharge machining of aluminum-based materials, the machining fluid used during electric discharge machining in the electric discharge machine contains one or more cations selected from potassium ions, calcium ions, sodium ions, and magnesium ions, and one or more anions selected from sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions, thereby enabling the electric discharge machine to extend the life of its filter.

[0039] (Appendix 2) In the electric discharge machine described in Appendix 1, the potassium ions, calcium ions, sodium ions, magnesium ions, sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions contained in the machining fluid used during electric discharge machining in the electric discharge machine may be ions contained in the machining fluid by adding a chemical to the machining fluid. This makes it possible to include these ions in the machining fluid in a simple manner.

[0040] (Appendix 3) In the electric discharge machine according to Supplementary Note 1 or 2, the electric discharge machine may have an ion exchange resin, and the sodium ions and hydroxide ions contained in the machining fluid used during electric discharge machining in the electric discharge machine may be ions contained in the machining fluid by passing the machining fluid through the ion exchange resin. This allows these ions to be contained in the machining fluid in a simple manner.

[0041] (Appendix 4) In the electric discharge machine according to any one of Supplementary Note 1 to Supplementary Note 3, the electric discharge machine may generate aluminum oxide and aluminum oxide trihydrate by electric discharge machining the aluminum-based material, thereby enabling the electric discharge machine to extend the life of a filter.

[0042] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the invention or the idea and intent of the present invention derived from the content described in the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0043] 10...Wire electric discharge machine

Claims

1. An electric discharge machine having a filter for filtering a machining fluid used in electric discharge machining to remove sludge contained in the machining fluid, The machining fluid used when electric discharge machining an aluminum-based material contains one or more cations selected from potassium ions, calcium ions, sodium ions, and magnesium ions, An electric discharge machine in which the cations are contained in the machining fluid to suppress the generation of aluminum hydroxide, which tends to clog the meshes of the filter, in the machining fluid during electric discharge machining of the aluminum-based material.

2. 2. The electric discharge machine according to claim 1, The electric discharge machine, wherein the machining fluid further contains one or more anions selected from the group consisting of sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions.

3. 3. The electric discharge machine according to claim 2, the potassium ions, the calcium ions, the sodium ions, the magnesium ions, the sulfate ions, the sulfite ions, the disulfite ions, the hydrogen sulfite ions, the hydroxide ions, the nitrate ions, and the nitrite ions are ions contained in the machining fluid by adding a chemical agent to the machining fluid.

4. 4. The electric discharge machine according to claim 2 or 3, Contains an ion exchange resin, The sodium ions and hydroxide ions are ions contained in the machining fluid by passing the machining fluid through the ion exchange resin.

5. The electric discharge machine according to any one of claims 1 to 3, An electric discharge machine that generates aluminum oxide or aluminum oxide trihydrate by electric discharge machining the aluminum-based material.

6. 1. An electric discharge machining method using an electric discharge machine having a filter that filters a machining fluid used in electric discharge machining to remove sludge contained in the machining fluid, Electric discharge machining of an aluminum-based material is performed in the machining fluid containing one or more cations selected from potassium ions, calcium ions, sodium ions, and magnesium ions; an electric discharge machining method in which the cations are contained in the machining fluid to suppress the generation of aluminum hydroxide, which tends to clog the pores of the filter, in the machining fluid during electric discharge machining of the aluminum-based material.

7. 7. The electric discharge machining method according to claim 6, The electric discharge machining method, wherein the machining fluid further contains one or more anions selected from the group consisting of sulfate ions, sulfite ions, disulfite ions, hydrogen sulfite ions, hydroxide ions, nitrate ions, and nitrite ions.

8. The electric discharge machining method according to claim 7, An electric discharge machining method in which a chemical agent is added to the machining fluid, thereby causing the machining fluid to contain the potassium ions, the calcium ions, the sodium ions, the magnesium ions, the sulfate ions, the sulfite ions, the disulfite ions, the hydrogen sulfite ions, the hydroxide ions, the nitrate ions, or the nitrite ions.

9. 9. The electric discharge machining method according to claim 7 or 8, The electrical discharge machining method includes passing the machining fluid through an ion exchange resin to cause the machining fluid to contain the sodium ions or hydroxide ions.

10. The electric discharge machining method according to any one of claims 6 to 8, an electric discharge machining method, in which the aluminum-based material is electric discharge machined in the machining fluid, thereby generating aluminum oxide or aluminum oxide trihydrate in the machining fluid.

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