Electrical Discharge Machining & Electrochemical Machining
Mi-Tech's tungsten composites are used worldwide for electrical discharge machining (EDM) and electrochemical machining (ECM) electrodes. All material is manufactured by the press, sinter, and infiltrate process. Virgin powders are used, which results in a consistent, homogenous material giving high, even burning rates. Copper tungsten is used in plunger/sinker applications where intricate definition is required, especially in tungsten carbide.
Mi-Tech’s CW70E (68% Tungsten & 32% Copper) is most commonly used for EDM electrodes. There are circumstances that require material with higher tungsten content. In these instances, CW75 (75% Tungsten & 25% Copper) or CW80 (80% Tungsten & 20% Copper) are used. The use of these materials results in sharper detail and superior surface finish. Typically, as the tungsten percentage decreases, you end up with a faster burning rate and some loss of definition and finish. Often it’s a trade-off, because the higher percentage tungsten materials are slightly more costly.
These tungsten composites are readily machinable. Carbide tooling is recommended.
There are some applications where silver is used as EDM electrodes. Mi-Tech’s SW74 (74% Tungsten & 26% Silver) is the most commonly used.
CW75 is the standard for ECM electrodes, because of its thermal and electrical characteristics and its ability to withstand erosion.
Availability: Diameters are stocked in 8" and 12" lengths. Other shapes and forms can be manufactured to specifications.
| Mi-Tech Grade | Nominal Composition % Weight | Rockwell Hardness | Electrical Conductivity % IACS | Ultimate Tensile Strength PSI | Cross Breaking Strength PSI | Density GMS/CC |
| CW70E | 68% Tungsten & 32% Copper | 88 B | 52 | 75,000 | 130,000 | 13.93 |
| CW75 | 75% Tungsten & 25% Copper | 94 B | 48 | 90,000 | 150,000 | 14.7 |
| CW80 | 80% Tungsten & 20% Copper | 98 B | 44 | 96,000 | 170,000 | 15.56 |
| SW74 | 74% Tungsten & 26% Silver | 90 B | 47 | ---- | ---- | 15.5 |
