Volumes of production

The process and shape can be controlled manually by an operator or from a CAD file, so it is equally suited to one-off pieces and automated mass-production.

Unit price vs. capital investment

Requires no tooling.

Speed

The latest generation of EDM machines can cut more than ½ square inch per minute, depending on the electrical resistance of the material and, of course, its thickness. A 2-inch piece of steel can be cut at a rate of approximately 1/6 inch per minute.

Surface

Wire EDM is well known for its ability to achieve an excellent finish.

Types/complexity of shape

The delicate wire can cut very intricate shapes from the toughest materials.

Scale

Depending on the material, the generator size, and the power, the process can cut through massive hunks of metal up to an astonishing 20 inches thick, although this will be very time-consuming, with cutting occurring at a rate of less than 1/25 inch per minute.

Tolerances

Wire EDM is extremely accurate and can achieve submicron tolerances.

Relevant materials

Restricted to conductive metals. The process is ideally suited to hard metals, the hardness of which does not affect the cutting speed.

Typical products

One of the big markets for this process is for the super-hardened dies and cutters that are used in industrial production. Other applications include supertough components for the aerospace industry.

Similar methods

Laser cutting (p.46) and electron-beam machining (EBM) (p.24).

Sustainability issues

Power consumption is very high, especially as the cutting rate is slow, which results in long cycle times. Leftover materials need to be melted down and recycled back into the process to reduce material consumption and waste.

Further information

www.precision2000.co.uk

www.sodick.com

www.edmmachining.com

Laser Cutting

with laser-beam machining

Product	Spiral
Designer	Torafu Architects
Materials	paper
Manufacturer	Kamino Kousakujo
Country	Japan
Date	2010

This is a paper bowl that envelops air. You can freely change its shape by molding it. The thin and lightweight paper gains tension and strength when pulled out. The soft, white color and delicate expressions of this airvase allow it to subtly blend into any scene.

Similar to water-jet cutting (see p.42) and electron-beam machining (see p.24), laser cutting is a non-chip-forming method of cutting and decorating materials. It is a highly accurate process based on input from a CAD file. In a nutshell, it works through a highly focused beam of light generating millions of watts of energy per square inch, which melts the material that is in its path.

Laser-beam machining is a form of laser cutting that uses a multi-axis head to cut three-dimensional objects. A CAD file maps complex paths for the powerful beam of light, resulting in fine, accurate designs.

Both processes can cut components that could not be cut precisely with conventional machine tools. As neither method involves contact with the material being cut, minimal clamping is required.

–  No tool wear, minimal clamping, and it offers a consistent, highly accurate cut.

–  Suited to a range of materials.

–  No post treatment of edges.

–  Has an optimum thickness from which materials can be cut, beyond which you might run into problems.

–  Can be time-consuming on large production runs, so it is best suited to one-off or batch production.