Improve the wear resistance of copper-tungsten electrode

Choose the best electrode material for carbide EDM

On the face of it, electrodischarge machining (EDM) of cemented carbide can be a tough business.

Determining the right set of parameters for job success may require time, attention, and careful fine-tuning. Unless you have established a good working relationship with the machine vendor support team, you may be out of luck - especially if you are in a race against the clock.

The choice of material used to manufacture electrodes for processes such as resistance spot welding and EDM has a huge impact on the results that can be achieved and the production deadlines that can be met.

In a series of blogs, we have discussed the various ways in which copper and tungsten can be selected as electrode materials to give edM an advantage. Here, we look at how tungsten wear resistance affects electrode efficiency and why copper and tungsten are such a good combination.

What is wear resistance?

As the name implies, wear resistance refers to the ability of a tool (such as spot welding or EDM electrodes) to resist wear under typical operating conditions. Wear resistance is influenced by many factors, such as the speed of processing and the heat generated.

It is well known that the edM of carbides is slow, which in turn greatly increases the wear rate. Therefore, it is very important to know the wear resistance of electrode materials when choosing electrodes.

Wear resistance of edM electrode materials is mainly determined by measuring end wear and angular wear:

Final wear is the amount of material burned off from the bottom of the material to the depth of the electrode to the cavity.

Angular wear is a measure of the length from the 90-degree outer Angle of the electrode to the corresponding inner Angle loss.

Together, these measurements determine the properties of the material throughout its lifetime. So, how does copper and tungsten stack up in wear resistance?

What properties of tungsten improve wear resistance?

Because EDM is a thermal process, the higher the melting point of the electrode material, the more it can withstand the high temperatures inherent in EDM.

One of the many interesting facts about tungsten is that, at 6,191 °F, it has the highest melting point of any metal. As a result, tungsten provides truly unparalleled thermal resistivity. Ultimately, this translates into better corner wear rates.

In addition, for applications where sharp corners and small cavities must be used, the composition of the copper-tungsten electrode can be adjusted to contain more tungsten to improve performance.

However, it is important to note the fact that the lower the copper content in the copper-tungsten electrode, the slower the cutting speed.

What are the advantages of copper and tungsten together?

The structural integrity of copper gives it a high dc arc resistance under severe flushing conditions, allowing it to still produce a very fine surface finish. Therefore, the electrode material composition can contain more copper for smoother combustion and better surface finish.

Combining the thermal resistivity of tungsten with the resistance of copper to dc arc allows the electrode to remain at sharp corners and helps prevent pitting of spark carbide.

By using the copper-tungsten electrode for carbide EDM applications, you can ensure productivity and cost savings, thereby improving the wear ratio of the electrode to the workpiece material.

For more information about copper tungsten billets for EDM electrode applications,

Please contact us at zhang@pride-cnc.com