Wire cutting – a versatile and precise machining method for challenging workpiece preparation

Wire cutting with over 30 years of experience

In manufacturing, our core competency is precision machining. We have six wire cutters at our disposal to achieve the accuracy of a thousandth of a millimetre. In addition to products requiring high precision, we specialise in wire cutting large cone angles, e.g. for different kinds of nozzles. We can undertake wire cutting at up to a 60-degree angle.

Our versatile machinery can produce the most challenging workpieces, and we can therefore undertake CNC milling, grinding, die-sink and spark drilling. The maximum working range of our wire cutters is 520 x 370 x 400.

What kind of machining is wire cutting suitable for?

Wire cutting is a versatile method of making extruder nozzles, active parts of cutters, and various machine parts with the precision of a thousandth of a millimetre. Difficult-to-cut shapes that cannot be machined by milling can often be wire cut. The more precise the dimensions and the more challenging the surface quality, the better suited the project is for wire cutting. Wire cutting is not limited to machining individual workpieces, but is also suitable for serial production.

To be wire cut, a workpiece must have sufficient electrical conductivity. The hardness of the workpiece is not important, i.e. the method allows all metals to be machined, including carbide. Its advantage is a very good surface quality, which often eliminates the need for post-grinding. Because wire cutting can also be used to process materials heat-treated to their working strength, subsequent significant changes in shape and dimensions are avoided. Best available surface quality is 0.3µm Ra.

What is wire cutting?

Wire cutting is undertaken with an electrically conductive wire inside dielectric fluid. This generates electrical discharges which cut the workpiece precisely. Wire cutting is based on the same principle as die-sink. In all spark processing methods, the basic elements of the machining operation are the dielectric fluid, the workpiece and the electrode. The die-sink electrode has the same shape as the desired machined workpiece. In wire cutting, the electrode is a mobile wire made of a conductive material. The workpiece is cut with the electrode wire. Wire cutting can produce complex shapes. The shapes must be extendable through the workpiece.

The wire cutter basically does two things: Produces regular electrical impulses and controls the electrode wire. The workpiece and electrode are connected to the opposite terminals of the electrical circuit. The wire cutter starts producing electrical impulses. When the electrode wire is close enough to the workpiece, the dielectric fluid changes from insulator to conductor and a high-energy breakthrough occurs. The electrical discharge heats the surface of the workpiece in a small area. Some of the material in the surface of the workpiece melts and a hole is formed in the workpiece. The size of the hole depends on the strength of the current and voltage. When a sufficient number of breakthroughs occur, the electrode wire moves through the workpiece and processes the programmed shapes set in the wire cutter.

The distance between the electrode wire and the workpiece in which the electrical discharge occurs is called the spark gap. The electrode wire produces shapes that are larger than the programmed track by the width of the spark gap. Spark gaps are usually considered when programming the wire cutter. The smallest possible workable radius of the inner corner is the diameter of the electrode wire plus the spark gap. The wire cutter has 2-5 programmable axes. For mould making applications, 5-axis wire cutters are most often used. The programmable axes of the wire cutter are: electrode wire guide, wire tilt in x and y directions, movement of a workpiece or wire transport system in x and y directions.