EDM Oil Composition Balancing Machining Speed and Insulation

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Solution Overview

Problem

The machining speed in electrical discharge machining, both for metal and insulative materials, is not adequately improved by existing electrode materials and methods, necessitating a focus on enhancing the machining oil composition.

Innovation Solution

An electrical discharge machining oil composition is developed, comprising a base oil and an organic acid metal salt with a metal having low electronegativity, specifically zinc, which provides a high volume resistivity and kinematic viscosity, enhancing machining speed and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional machining oils are used in electrical discharge machining, then the process can operate, but the machining speed remains low and productivity is insufficient

Engineering Contradiction:
Improvemachining speedVSAvoidinsulation performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the machining oil by introducing organic acid metal salts with specific electronegativity values (≤2.0) and controlling their concentration (0.01-5% by weight). This modifies the oil's electrical and physical properties to achieve both high machining speed and reliable insulation performance simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite machining oil system by combining base oil with organic acid metal salts (such as zinc stearate, calcium oleate) to form a new composition that exhibits superior electrical discharge characteristics compared to conventional single-component machining oils

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If the auxiliary electrode method is used to machine insulative materials, then insulative materials can be machined, but the machining speed is lower than in typical electrical discharge machining

Engineering Contradiction:
Improveability to machine insulative materialsVSAvoidmachining speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent modifies the machining oil parameters specifically for auxiliary electrode machining of insulative materials by using organic acid metal salts with low electronegativity (≤2.0), which enhances the dielectric breakdown characteristics and allows faster discharge rates while maintaining the ability to machine insulative materials

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The composition significantly increases machining speed, allowing for efficient processing of both metal and insulative materials, including brittle ceramics and ultrapure silicon, while maintaining high insulation performance and reducing the risk of short-circuits.

Implementation Method 1

the composition has a volume resistivity at 80 degrees C of 2×10^12Ω·cm or more

Methodology Applied
Scientific EffectElectrical resistivity: Electrical Resistance

Implementation Method 2

provides a high volume resistivity and kinematic viscosity

Methodology Applied
Scientific EffectViscosity:

Implementation Method 3

The workpiece is brought into a high temperature condition by arc discharge to be melted

Methodology Applied
Scientific EffectArc discharge: Electric Arc

Implementation Method 4

The workpiece is brought into a high temperature condition by arc discharge

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 5

The melted workpiece is removed by vaporizing explosion of the heated and vaporized machining oil

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 6

The melted workpiece is removed by vaporizing explosion of the heated and vaporized machining oil

Methodology Applied
Scientific EffectExplosion: Explosion

Data Source

PatentEP3127643B1Oil composition for electrical discharge machining
Publication Date: 2024.05.08 IDEMITSU KOSAN CO LTD
  • EP3127643B1 patent drawingFigure 1
  • EP3127643B1 patent drawingFigure 2
  • EP3127643B1 patent drawing

AI summary

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 × 10-5TΩ·m or more and a kinematic viscosity at 40 degrees C in a range from 0.5 mm2/s to 10 mm2/s.