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What is EDM?

1. What is a wire for EDM machine?

What is EDM?

There is a machining method that uses a high voltage electrical discharge phenomenon for cutting metal. Two types of tools utilize this method, the wire EDM machine and the die-sinking EDM machine. The term wire for EDM machine refers to the wire that is used to generate the electrical discharge in the wire EDM machine.

2. How the wire for EDM machine is used

Wire EDM generates an electrical discharge between the work piece (metal) and the wire for EDM machine, as the wire is continuously fed. This melts and cuts the metal in a way similar to a fret saw.
The diameter of the wire is determined according to the shape and thickness of the metal to be machined. A wire of 0.1 to 0.3mm in diameter is typically used. The metal to be machined is melted and cut by the discharge, but the wire is partially consumed at the same time, as a discharge trace is formed. (The trace is created when the wire surface melts and splatters.)
The partially consumed wire has insufficient strength to withstand any significant tension. Therefore, new wire must be continuously supplied. The wire is sold on a bobbin, so that it can be continuously supplied during EDM.

  • * : The wire for EDM machine is a consumable item that is discarded after one use.

3. Types of wires for EDM machine

There are two main types of wire used for the main wire for EDM machine, brass wire and coated wire.

(1) General-purpose brass wire

Brass is an alloy of copper and zinc and has excellent discharge characteristics.
These discharge characteristics improve as the zinc content of the brass increases. However, it becomes difficult to form high zinc-content brass into a thin wire, because the malleability of the brass is reduced.
Brass with 35% to 40% zinc content is widely used, considering the balance between product performance and machining characteristics.

OKI product line-up
Model No. Wire diameter Quality Paraffin Alloy No. Tensile strength Elongation
OB-P 0.1 to 0.3mm Hard material Yes JIS H 3260 C2700W > 980 N/mm2 < 3 %
OB-PZ 0.1 to 0.3mm JIS H 3260 C2800W > 980 N/mm2 < 3 %
OB-PN 0.07 to 0.3mm No JIS H 3260 C2700W > 980 N/mm2 < 3 %
OB-PZN 0.1 to 0.3mm JIS H 3260 C2800W > 980 N/mm2 < 3 %
OB-B 0.1 to 0.3mm Soft material Yes JIS H 3260 C2700W > 442 N/mm2 < 20 %

(2) Coated wire

A number of the characteristics of the single-layer structure have limitations. The coated wire has functionality that overcomes these limitations.
Currently, the main types of coated wire on the market are zinc-coated wire and diffusion-annealed wire.

OKI product line-up
Model No. Wire diameter Type Paraffin Tensile strength Elongation
OS-Z 0.1 to 0.3mm Zinc-coated Yes > 883 N/mm2 < 3 %
OS-UZ 0.2 to 0.3mm Diffusion-annealed Yes > 900 N/mm2 < 3 %

Types of wires for EDM machine

4. OKI's commitment to wire for EDM machine

Since OKI began selling wire for EDM machine in 1976, the product has been well received by the market. OKI's customers can be found across Asia, North America, and Europe, as well as in Japan. For the future, OKI will continue to broaden the manufacturing know-how it has cultivated for over 30 years, so that OKI's products become a favorite the world over. Moreover, OKI will further improve wire products to meet their customers' needs, and bring new products to the market.

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