Knowledge Hub


What is Spark Erosion?

Spark Erosion

Spark erosion is a machining process where a specific shape is obtained using electrical discharges.

Material is removed by generating sparks between an electrode and the workpiece.

It is often adopted in circumstances where complex or intricate shapes need to be engineered. Often, these shapes would be too challenging to create using conventional cutting methods. It is also employed when dealing with challenging or robust materials.


Spark erosion is known in the industry by many different terms, some of which you may have heard of before. For instance, you may have heard it referred to as electrical discharge machining (EDM), spark machining, or die machining.

Regardless of what name you may know it by, spark erosion can be an invaluable part of the metal fabrication process.

Let’s look at the process itself in more detail…

The Process

Spark erosion is performed on hard metals, most commonly either on aluminium or steel.

The process involves removing material.

This is achieved by two electrodes, which are mounted on the machine. Current is discharged between the two electrodes and the process is supported by an electric voltage.

Dielectric fluid is used to ensure that electric charges do not flow through the workpiece. It helps to insulate the workpiece until discharge can occur. This fluid also acts as a coolant for the workpiece and the electrode. This is an important part of the process as temperatures can become very high.

The cutting tool moves along the object, cutting a path as it goes. At no point in the process does the cutting tool itself ever touch the surface of the metal.

Sparks move between the workpiece and the electrode, where electrical energy becomes heat, and results in the melting of the work material.


Advantages of Spark Erosion

– A fine level of detail can be achieved. This is particularly important when working on projects where tight tolerances are required
– Supports projects where complex machining is necessary
– Used for a wide range of surface finishes/textures
– Harder materials can be cut more quickly compared to conventional machining methods
– No cutting contact, so the integrity of the material is always maintained
– Highly controlled process which allows for precision and accuracy, even on softer materials
– Versatile in its applications to metal. Spark erosion can be applied to many different types of metal, as long as they have low levels of electrical conductivity
– Ideal for jobs which require the drilling of very small holes

Spark Erosion at RP Technologies

Here at RP, spark erosion is a fundamental part of what we do, and it has been used on several key projects for many of our customers. It has enabled us to create tools which meet the specific requirements of the drawing specification.

Many of our competitors do not use spark erosion. Instead, they ask their customers to change their design so that it is less complex and can be machined more easily.

These changes can be time consuming and costly.

Our “Without Limits” philosophy means that we build tools to meet the specific needs of our clients, no matter how complex the component design or process.

Sometimes, we employ spark erosion to achieve this. Indeed, it has become such an important part of what we do that we want to ensure we are as well prepared for the challenge as possible.

Consequently, we have recently promoted one of our tooling engineers, Garry Duffield, to the full-time position of EDM Engineer. After receiving three months of intensive onsite training, Garry has now also completed a three-day training course at Sodick.

Our Use of Spark Erosion

We were recently asked by a new client to help them with a new-to-market product which was designed to improve environmental sustainability in the farming and agriculture sector.

The design of the product itself was so complex that many of our competitors would not have been able to produce the parts in a manner which was faithful to the original drawings.

The features were incredibly complex, and the shaping was so intricate that it required some very high precision engineering. One of the main problems was that we were unable to cut using traditional cutting methods and machines.

We engaged in open dialogue with the client, supporting them to achieve their original vision for the product. We gave them advice and guidance and talked them through the potential solutions.

Through some further in-house discussion between our CAD designers and production engineers, we decided that the only way to maintain the integrity of the design would be to use spark erosion.

We used our own onsite Sinker EDM AD55L machine to do this. This machine features Sodick’s Linear Motor Technology. It provides rapid acceleration while ensuring optimum performance at high speeds. It also reduces distortion and improves rigidity by 70%.

This machine allowed us to overcome the complexity of the engineering requirements, achieve a fast turnaround of parts, and to ensure a smooth finish without any flaws or discrepancies.

Our client was incredibly happy with the finished components, complimenting us on our speed of delivery, final product quality, and the way in which we were able to find an ideal solution to a complex problem.

action image
We can put your plans into action today

Award-winning aluminium tooling, plastic injection moulding, CNC machining, and rapid prototyping. We specialise in fast turnarounds of high quality components.

Want to know more? Get a quote