Graphite Archives

Erodex Group, UK leaders in the design and manufacture of graphite electrodes, tooling and fixtures are celebrating 50 years in business by investing £400,000 in automation at their state-of-the-art graphite machining facility in the West Midlands.

Celebrating 50 years

2023 marks 50 years in business for the family-owned firm, who are looking to the future with the purchase of an automated pallet loading system to work in coordination with existing high speed machining centres.

As a result of the investment, the company expects to maximise efficiencies and output within a high-volume area of the business; creating capacity without the need to layer in additional shift patterns.

In addition, the alignment of existing machining capacity with automation provides Erodex with a portfolio that it has previously been unable to offer customers, therefore creating new business opportunities.

Erodex state of the art machine machining facility in Darleston.

Investment into the machine shop will keep Erodex at the forefront for Graphite machining.

The company’s state of the art machining facility in Wednesbury has been established for over 35 years, enabling Erodex to machine its wide variety of graphite grades into highly complex components for a range of industries. It has also been a key driver in the significant growth that the Erodex Group has experienced in recent years, following a £1.75million investment in new machinery in 2021.

Steve Rolinson, Director at Erodex Group, comments:

“We are very proud to celebrate 50 years in business, which is a significant milestone for the Erodex Group.

“The fact that we continue to go from strength to strength as a business is testament to the fantastic, loyal workforce that we have here, many of whom have been with us for a significant amount of time.

“Further investment in our machining facility represents the next stage of evolution for the business. Since the mid-1980s the Erodex Group has enabled our customers to benefit from the capabilities of our ISO 9001 accredited graphite machining facility, which is widely regarded as the best graphite machining facility in Europe.

“Continued planned investment as part of our continuous improvement programme – including that in automation – means that we are well placed to capitalise on market opportunities moving forward and further reinforces our position as UK leaders in the design and manufacture of graphite electrodes, tooling and fixtures for the aerospace and IGT sectors”.

Directors of Erodex Group Ian (facing) and Steve Rolinson

Erodex investing in their employee’s, with up-skilling and further training set to future proof the workforce.

Alongside the automation investment, Erodex continue to invest in the upskilling of its’ employees; placing 2 Operators on additional CAD training and will continue this investment in people through the short and medium term. The company is also set to relaunch its’ apprenticeship scheme this coming summer, developing the next generation of engineers and further future proofing the workforce.

Founded in 1973, the Erodex group employs 90 people across two sites in the West Midlands with headquarters in Halesowen alongside the Wednesbury based machining facility.

There has been a long standing debate about whether graphite or copper is a better EDM electrode material. One of main reasons people have historically used copper within Electrical Discharge Machining (EDM) is because it is cleaner in their working environment, but is that where the advantages of the material stop? With over 70% of the global market choosing to use graphite electrode materials over copper today (totalling as high as 95% in the United States), the question is why choose graphite over copper in your EDM applications? Here, we take a closer look at the differences between the two materials and outline 5 reasons why graphite is likely to be the most appropriate for your EDM application needs.

1. Electrode Cost

In terms of material cost, it is commonly assumed that copper is lower priced than graphite. This is often the result of comparing the price of copper material with more expensive grades of graphite available. Due to the wide range of graphite materials available, it is proven that some EDM grades are more economical than copper. Furthermore, most comparisons do not consider the cost of machining the electrode. Significant cost savings can be made choosing graphite over copper, generated through reduced machining times and speed of cut, less production time to create electrodes, faster EDM times and better throughput from EDM machines. For example, due to the soft ‘ductile’ characteristics of copper, the material is often ‘gummy’ and conventional machining practices, such as feeds and speeds must be altered to successfully machine this material. This results in longer machining times and increased costs. In comparison, graphite can be conventionally machined much more easily and quickly and even with more expensive graphite materials, the machining costs often offset any savings that are realised when choosing copper.

2. Material Variety

Graphite is produced with a wide range of material characteristics in order to allow matching the electrode material properties to the EDM application. Less critical applications with electrode features containing a large radius, an open tolerance or minimal EDM requirements would use an electrode with large particles, lower strength and economical price. A highly detailed EDM electrode however with critical features, extreme tolerance and stringent EDM requirements would entail a more premium graphite electrode to fit the needs of this application. On the other hand, the types of copper available on the market are few and minimize the ability to match the material characteristics to the EDM application, thus limiting optimum performance.

3. Electrode Detail

Copper does not have the ability to handle current density as effectively as graphite, which performs exceptionally well at a high current density even with complex geometry, allowing for various intricate machined details to be designed on the same electrode. The result is that the number of electrodes required to perform a job is significantly reduced.

With the large number of graphite grades Erodex offer, they can carefully select the correct material for a specific job. Graphite can be chosen depending on required surface finish, electrode life, speed of cut or metallurgy of the job. When working with copper however, there is only one form and precisely selecting the optimum material specification is not possible.

4. EDM Performance

EDM operators know that excessive wear results in the use of extra electrodes or frequent redressing. Graphite is able to achieve electrode wear of less than 1% in relation to the depth of cut, while working to more aggressive machine parameters. This means, unlike copper, the high amperage and longer on-times actually preserve the graphite electrode.

In the aerospace sector when working with very thin, fine detail electrodes, copper is vulnerable to any rough handling and physical damage. Pressure applied to a thin section of copper will cause movement that can go unnoticed, causing further performance issues at a later stage. Graphite on the other hand is either in the right condition, or is clearly broken, vastly reducing the risk of the electrode being used in production.

Some firms wire erode their own electrodes and are mislead into believing that you cannot wire erode graphite. Contrary to this, Erodex have tested the wire erosion of graphite and have done so without any breakages and at comparible speed times to that of copper.

5. Surface Finish

Copper electrodes do provide very fine surface finishes. With the sophistication of today’s EDM machine technology, the surface finish gap between graphite and copper has narrowed significantly. For example, fine grain graphite electrodes are able to deliver similar surface finishes to that of copper, while offering much faster speeds and vastly reduced electrode wear.