Electric discharge machining (EDM) electrodes require graphite because it ensures less electrode wear, faster metal removal rates and both the preferred surface finish and tolerance. Our EDM electrodes are widely used for EDMing automotive forging molds, plastic injection molds and aluminum extrusion canisters. EDM graphite is marketed on the international market as HK grades.
HK Grades
The materials and grades recommended by Tokai Carbon for these applications are shown in the table below:
| Material Type | Avg Density
(g/cm³) |
Specific Resistance
(µΩm) |
Flexural Strength
(MPa) |
Hardness
(Shore) |
Avg Grain Size
(µm) |
| HK-0 | 1.8 | 12 | 39 | 56 | 13 |
| HK-1 | 1.85 | 11 | 50 | 58 | 11 |
| HK-10 | 1.84 | 12 | 52 | 54 | 9 |
| HK-15 | 1.83 | 12.5 | 54 | 62 | 7 |
| HK-20 | 1.86 | 12 | 66 | 60 | 6 |
| HK-2 | 1.82 | 13.5 | 64 | 64 | 7 |
| HK-75 | 1.82 | 15 | 66 | 72 | 4 |
| HK-3 | 1.84 | 15.5 | 88 | 78 | 2 |
| HK-6 | 1.86 | 12 | 85 | 68 | 3 |
| HK-2C | 2.79 | 2.3 | 77 | 67 | 7 |
| HK-6C | 2.68 | 3.1 | 110 | 70 | 3 |
