Coated Wire That Performs out of this World

As the UK’s largest supplier of EDM consumables, Erodex is the only company to stock every wire diameter in every reel size, with all tensile strengths and with every coating option. That amounts to around 70 line items that can be sent to customers for next day delivery. “We have enough wire in stock to reach the moon and back; and we regularly ship 30 to 40 orders a day for customers looking for reliable service and support. We provide everything for EDM users, except the machines, using a full service approach.” explains Sales Director, Steve Rolinson.

With an extensive stock of filters, electrode blanks and other consumables, the staff at the company are always willing to share their knowledge and experience with EDM users looking to improve productivity. One of the greatest performance improvements comes from using coated wire rather than plain brass during the wire cutting process. Erodex supplies the complete Bedra range of high performance coated wires that can provide an increase of up to 50 per cent cutting speed performance while maintaining the quality of the cut.

Steve Rolinson says: “For the efficient application of the wire EDM process Bedra has contributed significantly to the development of technology and production processes. With the functional coatings for wire electrodes it has developed, an enormous increase in material removal performance, and hence in productivity, can be achieved. Moreover, a reproducible high precision and surface quality is attained.”

Erodex highlight the high-tech, universal Topas Plus wire cutting range that has been developed as a high speed cutting wire. Combining an excellent price-performance ratio for applications on all standard EDM machines, this range can significantly improve productivity compared to brass wire.

The Topas Plus range offers different zinc coating levels on the core of the wire to suit the various EDM machines available. “Between the core and the coating is another layer called the Gamma Phase area that energizes the material difference between the core and the zinc to give a much more powerful spark. The enriched zinc coating on a copper, steel or brass core fractures to provide an increased surface area for the spark, which increases the cutting speed,” Steve Rolinson states.

In recent wire cutting tests held at Warwick Machine Tools showroom in Kenilworth, the Megacut Plus range was benchmarked on an Excetek Wire Cut machine against standard brass wire and provided a 20 per cent increase in the cutting speed. This was achieved with no alterations made to the machine’s cutting technology. “We were impressed by the initial results,” says WMT’s Managing Director, Ian Holbeche. “So we approached an existing customer with the findings and conducted further tests on an Excetek V850 machine installed on the shopfloor. The results were remarkable, in a production environment with operators that have an in-depth knowledge of the machine you can tweak the parameters and we achieved a 50 per cent increase in cutting speed, even during complex profile cutting.”

Erodex provide EDM users with a cost comparison spreadsheet that will calculate the savings that could be achieved by using these new generation coated wire. Steve Rolinson concludes: “Of course the coated wire is more expensive initially. However, if you can increase the throughput of the machine tool by between 20 and 50 per cent the business efficiency gains far outweigh the additional cost of the consumable wire.”

For more information on topas wire or any of the Berkenhoff range, please click here.


5 Reasons to use Graphite EDM Electrodes

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.


Record growth for EDM graphite & tooling specialists after £3.5million investment

Erodex UK Limited, the UK’s leading supplier of EDM graphite & tooling to the aerospace market, has experienced record levels of growth following a £3.5million investment and expansion into North America.

Overall turnover increased 20% during the last financial year, following previous record years for the firm. The growth has been a direct result of the investment, specifically targeted at work within the aerospace and industrial turbine sectors.

Director Steve Rolinson comments: “We have experienced significant growth on the tooling side of the business, which in fact is the fastest growing part of the Erodex group. The decision to invest in our own tool rooms and dedicated tooling inspection facilities has given us a real point of differentiation in the market. As well as designing the optimum electrode, the electrode holder and work piece holder, Erodex design and manufacture the whole package, all with a single point of contact. This is unique in our market and we are seeing more and more customers buying into this mindset because of cost and time savings”.

As well as picking up a number of new clients in China and Israel, the company have benefitted from their decision to establish a new £2million facility in Virginia, North America as well as investing £1.5million in a new UK tool room and machine shop. The decision to create a new UK tool room enables Erodex to produce their own tooling in house – particularly that with a significant amount of intellectual property. Doing so allows for tighter quality control, greater support and the carrying out of function trials by their own toolmakers prior to release.

Regarding the expansion into America, co-Director John Rolinson adds: “Rolls Royce Group announced that they were opening a new turbine blade facility in Virginia and Erodex were asked to support that as a result of our long term working relationship with them. This started off with us supplying graphite electrodes from the UK, however as their Virginia operation grew, we entered conversations about starting a tool room there so that we could offer the same fixture care and repair as well as inspection/trialling of tools in Virginia that we would do in the UK”.

To facilitate the growth, Erodex have expanded their workforce by 10% to above 100, taking on three experienced aerospace tool makers, a Tooling Manager, two Project Managers, Designers and more CNC operators. A Group Quality Manager and Group Quality Engineer were also recruited as part of a move towards AS9100 Rev D, ISO14001 and NADCAP Certifications.

Steve Rolinson adds: “The move towards AS9100 Rev D, ISO14001 and NADCAP Certification will allow further diversification of Erodex into flying parts. We currently make the electrodes required to make flying parts, but accreditation such as this will enable Erodex to handle and inspect flying parts ourselves, which is part of our longer term strategy for growth”.