Four calculators in one place. MRR, electrode wear, surface finish Ra, and wire EDM cutting speed. All the numbers you need on the shop floor, no login, no paywall.
MRR in EDM depends on discharge energy per spark and how many sparks you fire per second. Higher energy or higher frequency means more metal removed per minute. But there is always a tradeoff with surface quality and electrode wear.
| Material | Hm (J/mm³) | Melting Point | EDM Difficulty |
|---|
The electrode also wears away as it machines. The wear ratio tells you how much electrode volume is lost per unit of workpiece removed. Compensation depth tells you how much extra electrode length you need to account for in your program.
| Material | Wear Ratio (%) | Conductivity | Best For |
|---|---|---|---|
| Copper (Cu) | 0.5 to 2% | Excellent | Fine finishing, complex shapes |
| Graphite | 2 to 8% | Good | Roughing, large cavities, cheaper cost |
| Copper-Tungsten | 0.1 to 1% | Good | Carbide, high accuracy jobs |
| Brass | 5 to 15% | Good | Wire EDM guide dies |
| Tungsten | 0.1 to 0.5% | Moderate | Very fine features, micro EDM |
| Silver-Tungsten | 0.05 to 0.3% | Excellent | Precision micro holes |
Surface roughness in EDM is controlled mainly by peak discharge current and pulse-on time. More energy per spark means bigger craters, which means rougher surface. This gives you an estimated Ra value. Actual finish varies with dielectric flushing and machine condition.
| Operation | Ra (µm) | ISO Grade | Typical Ip (A) | Typical ton (µs) |
|---|---|---|---|---|
| Rough EDM | 6.3 to 25 | N9 to N11 | 50 to 500 | 100 to 2000 |
| Semi-finish EDM | 1.6 to 6.3 | N7 to N9 | 10 to 50 | 20 to 100 |
| Finish EDM | 0.4 to 1.6 | N5 to N7 | 2 to 10 | 5 to 20 |
| Fine finish EDM | 0.1 to 0.4 | N3 to N5 | 0.5 to 2 | 1 to 5 |
| Mirror EDM | below 0.1 | N1 to N3 | 0.1 to 0.5 | 0.1 to 1 |
Wire EDM cutting speed is measured in mm/min feed rate through the material. It depends on material thickness, discharge power, and wire diameter. This calculator gives you estimated cutting speed and total machining time for your job.
| Material | Thickness (mm) | Speed (mm/min) | Ra (µm) |
|---|---|---|---|
| Steel (die steel) | 20 | 2.5 to 3.5 | 1.6 to 2.5 |
| Steel (die steel) | 50 | 1.5 to 2.0 | 1.6 to 2.5 |
| Aluminium alloy | 20 | 4.0 to 6.0 | 2.0 to 3.2 |
| Aluminium alloy | 50 | 2.5 to 4.0 | 2.0 to 3.2 |
| Carbide (WC-Co) | 10 | 0.8 to 1.5 | 0.4 to 0.8 |
| Carbide (WC-Co) | 20 | 0.5 to 1.0 | 0.4 to 0.8 |
| Titanium alloy | 20 | 1.0 to 1.8 | 1.6 to 2.5 |
| Copper alloy | 20 | 2.0 to 3.0 | 1.6 to 2.5 |
Why I built this calculator? Honestly, because I was fed up paying for tools that Indian engineers should get for free.
Most EDM shops in India are running on experience and gut feel. That works, but having quick numbers to back up your process settings helps a lot when someone asks "why did you pick these parameters?" Now you can show them the math.
No login. No email signup. No ads. Just type your numbers and get your answer. That is the whole idea behind TaskJunction.