Oil composition for electrical discharge machining

Patent metadata

Field	Value
Publication number	US-9993889-B2
Application number	US-201515129490-A
Country	US
Kind code	B2
Filing date	Mar 27, 2015
Priority date	Mar 31, 2014
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

An electrical discharge machining oil composition of the invention includes an organic acid metal salt and a base oil, in which the organic acid metal salt is an organic acid salt of a metal having an electronegativity on Pauling scale of 2 or less, and the present composition has a volume resistivity at 80 degrees C. of 2×10 −5 TΩ·m or more and a kinematic viscosity at 40 degrees C. in a range from 0.5 mm 2 /s to 10 mm 2 /s.

First claim

The invention claimed is:

1. An electrical discharge machining method, comprising machining a brittle material using an auxiliary electrode method in the presence of an electrical discharge machining oil composition, wherein:
the electrical discharge machining oil composition consists essentially of a base oil, an organic acid metal salt, and at least one of a thickener, an oil-soluble resin, a rust inhibitor, an antifoaming agent, an antioxidant and a metal deactivator;
the organic acid metal salt is a salt of an organic acid and a metal having an electronegativity on Pauling scale of 2 or less; and
the composition has a volume resistivity at 80 degrees C. of 2×10 −5 TΩ·m or more and a kinematic viscosity at 40 degrees C. ranging from 0.5 mm 2 /s to 10 mm 2 /s.

2. The electrical discharge machining method according to claim 1 , wherein a content of the organic acid metal salt ranges from 0.5 mass % to 15 mass % in a total amount of the composition.

3. The electrical discharge machining method according to claim 1 , wherein the organic acid is carboxylic acid.

4. The electrical discharge machining method according to claim 3 , wherein the carboxylic acid is monocarboxylic acid.

5. The electrical discharge machining method according to claim 1 , wherein the base oil has a kinematic viscosity at 40 degrees C. ranging from 0.4 mm 2 /s to 9.9 mm 2 /s.

6. The electrical discharge machining method according to claim 1 , wherein the metal of the organic acid metal salt is at least one of Zn, Ba, Ca, Na and K.

7. The electrical discharge machining method according to claim 1 , wherein:
the composition includes the thickener; and
the thickener has a kinematic viscosity at 100 degrees C. ranging from 10 mm 2 /s to 10,000 mm 2 /s.

8. The electrical discharge machining method according to claim 7 , wherein a content of the thickener ranges from 0.5 mass % to 15 mass % in the total amount of the composition.

9. The electrical discharge machining method according to claim 1 , wherein the composition is adapted to function as an oil composition for machining the brittle material by the auxiliary electrode method.

10. The electrical discharge machining method according to claim 1 , wherein the brittle material is an insulative brittle material.

11. The electrical discharge machining method according to claim 1 , wherein the brittle material is at least one material selected from the group consisting of diamond, ruby, a glass, a ceramic and an ultrapure silicon.

12. The electrical discharge machining method according to claim 1 , wherein the machining occurs at a machining speed ranging from 0.18 mm 3 /min to 0.70 mm 3 /min.

13. The electrical discharge machining method according to claim 1 , wherein the brittle material is a ceramic, and the machining occurs at a machining speed ranging from 0.18 mm 3 /min to 0.23 mm 3 /min.

14. The electrical discharge machining method according to claim 1 , wherein the brittle material is a steel, and the machining occurs at a machining speed ranging from 0.66 mm 3 /min to 0.70 mm 3 /min.

15. The electrical discharge machining method according to claim 1 , wherein the electrical discharge machining oil composition consists of the base oil, the organic acid metal salt, and at least one of the thickener, the oil-soluble resin, the rust inhibitor, the antifoaming agent, the antioxidant and the metal deactivator.

Assignees

• Idemitsu Kosan Co
• Univ Nagaoka Technology

Inventors

• Kitamura Tomohiko
• Fukuzawa Yasushi
• Yamashita Ken
• Hanaoka Daiki

Classifications

• C10M2219/044

  Sulfonic acids, Derivatives thereof, e.g. neutral salts · CPC title

• C10M2205/026

  Butene · CPC title

• C10N2040/22

  with essential removal of material {, e.g. cutting, grinding or drilling} · CPC title

• C10M2207/12

  having carboxyl groups bound to acyclic or cycloaliphatic carbon atoms · CPC title

• C10N2040/16

  Dielectric; Insulating oil {or insulators} · CPC title