Electrode Wire Pits and Micro-Pits for EDM Cutting Speed

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Solution Overview

Problem

The gradual depletion of the high-zinc alloy layer and crack structures on the electrode wire surface during wire cut electrical discharge machining leads to a reduction in cutting speed due to diminished vaporization effect and flushing efficiency.

Innovation Solution

An electrode wire with a core material, an intermediate copper-zinc alloy layer featuring pits and micro-pits on its surface, and a surface layer that discontinuously covers the intermediate layer, enhancing flushing and cooling efficiency by increasing the contact area with the working fluid and facilitating easier discharge at the edges of these features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a high-zinc alloy layer is deposited on the electrode wire surface to increase cutting speed, then the initial cutting speed is improved, but the cutting speed decreases over time as the alloy layer is consumed

Engineering Contradiction:
Improvecutting speedVSAvoidservice life of electrode wire
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The electrode wire is segmented into multiple functional layers: a core material layer, an intermediate copper-zinc alloy layer with pits and micro-pits, and a surface layer that discontinuously covers the intermediate layer. This segmentation allows each layer to perform specific functions - the surface layer provides initial vaporization effect, while the underlying intermediate layer with pits maintains flushing efficiency throughout the service life

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate layer is pre-formed with pits and micro-pits before the electrode wire is put into service. These pre-formed structures ensure that when the surface layer is consumed, the flushing and cooling efficiency is already optimized, preventing the decline in cutting speed that occurs with conventional single-layer electrode wires

Inventive Principle:
Principle #10Preliminary action

2Productivity

If cracks are formed on the electrode wire surface to increase flushing efficiency and cutting speed, then the initial performance is improved, but the structural integrity and durability are compromised

Engineering Contradiction:
Improvecutting speedVSAvoidstructural integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Instead of creating cracks throughout the electrode wire structure, the invention applies localized pit structures only on the surface of the intermediate layer. This local modification provides the flushing efficiency benefits of cracks while maintaining the overall structural integrity of the wire, as the pits are confined to the non-structural surface and intermediate layers

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The surface layer is designed as a consumable, short-lived component that provides initial vaporization effect. As it is consumed during machining, the underlying intermediate layer with pits takes over the flushing function, effectively replacing the need for permanent crack structures that would compromise structural integrity

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 increased contact area and reduced spark generation time result in accelerated cutting speed during wire cut electrical discharge machining.

Implementation Method 1

the contact area between the electrode wire surface and the working fluid is significantly augmented. This enhances the flushing and cooling efficiency of the working fluid on the electrode wire

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

utilize a continuously moving thin metal wire (referred to as an electrode wire) as an electrode, which erodes metal through pulsed spark discharges

Methodology Applied
Scientific EffectElectrical discharge: Electric Spark

Implementation Method 3

resulting in the formation of an instantaneous high-temperature heat source within the electrode gap. This causes local melting and vaporization of metal

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 4

By leveraging zinc's low sublimation temperature, a high discharge-induced vaporization pressure is attained during machining, thereby increasing the cutting speed

Methodology Applied
Scientific EffectSublimation: Sublimation

Data Source

PatentEP4628237A1Electrode wire for electric spark discharge machining, and preparation method therefor
Publication Date: 2025.10.08 NINGBO BOWAY ALLOY HIGHTECH WIRE CO LTD
  • EP4628237A1 patent drawingFigure 1~2
  • EP4628237A1 patent drawingFigure 3~4
  • EP4628237A1 patent drawingFigure 5~6

AI summary

An electrode wire for electrical discharge machining and a preparing method thereof. The electrode wire comprises: a core material (1); an intermediate layer (2) located externally to the core material (1); and a surface layer (3) located externally to the intermediate layer (2). Wherein, the material of the core material (1) is a metal or an alloy, and the material of the intermediate layer (2) is a copper-zinc alloy. The intermediate layer (2) has pits (20) on its surface, and the pit (20) has micro-pits (200) on its surface. The size of the micro-pit (200) is smaller than that of that of the pit (20) on which the micro-pit located. The surface layer (3) discontinuously covers the exterior of the intermediate layer (2) and fills the pits (20) and micro-pits (200). During the preparing process, the copper-zinc alloy is formed inside the electrode wire through electroplating, heat treatment, and drawing processes, while pits (20) and micro-pits (200) are formed on the surface of the intermediate layer (2) via extrusion.