Copper tungsten is produced by taking high quality copper and tungsten powders and mixing these together. This mixture is then either pressed into blocks or plates, or extruded into bars, tubes or wires. ( Sheets are produced by rolling thin plates down ). The formed mixture is then sintered at high temperature under inert atmosphere.
The typical method for EDM is 70% tungsten to 30% copper (sheet stock is typically 60% tungsten to 40% copper). Other grades containing a higher tungsten content are available. This mix of tungsten to copper combines the strength, high density and high melting point of tungsten with the excellent electrical properties and good resistance against DC arcing of copper to form an unbeatable combination.
Copper Tungsten is recommended as one of the best electrode materials to use when minimum electrode wear is required to hold fine detail and definition. Copper tungsten is also recommended when limited flushing exists, as with intricate cavities and deep slots, to minimise the possibility of DC arcing and produce favorable electrode wear with excellent surface finish.
Copper tungsten electrodes can be used to erode any type of work piece and highly recommended when eroding tungsten carbide, nickel super alloys and other exotic materials.
Copper tungsten electrodes can be machined using high speed steel cutting tools, however, we recommend using tungsten carbide cutting tools whenever possible due to the extreme hardness of copper tungsten. Copper tungsten can be ground with standard grinding wheels.
The disadvantages of using a high tungsten content are a slow EDM performance, difficulty in machining and its high cost.