SPARK EROSION

Spark erosion refers to an electrothermal erosive production process for conductive materials that takes place between an electrode (tool) and a conductive workpiece as a result of electrical discharge processes (sparks).

The processing takes place in a non-conductive medium, referred to as the dielectric (in most cases oil or deionised water).

This involves moving the electrode towards the workpiece until the gap is sufficiently narrow for a spark to cross over, which melts and evaporates the material. Different erosion results are attained, depending on the intensity, frequency, duration, length and gap width of the discharges. Even complicated geometrical shapes can be produced. The electrode material can be copper, brass, graphite or copper alloys (in most cases with tungsten) and carbide.

A distinction is made between

• spark-erosion drilling (drill erosion)
• spark-erosion cutting (wire erosion),
• spark-erosion countersinking (cavity erosion), in which the electrode is "pressed" into the workpiece as the negative shape with the aid of a spark erosion machine.

Cavity erosion

The electrode has the negative shape of the workpiece surface being made. This enables defined blind holes to be created.

• The area of use for cavity erosion beings where the mechanical machining of difficult-to-cut materials reaches its limits (e.g. in the case of deep and narrow cavities or very complex surfaces).

• Very hard materials can be machined

• Surface textures of variable roughness can be created.

"(Source: Wikipedia)"