What EDM oil does in the gap

In sinker EDM and oil-based wire EDM the fluid is part of the process, not just a coolant. It insulates the electrode from the workpiece until the voltage is high enough for a controlled spark, then recovers its insulation between pulses. At the same time it cools the zone around each discharge and flushes the eroded particles out of the gap. If any of these four jobs slips, the spark becomes unstable, the electrode wears faster and the surface finish suffers.

How the oil behaves at each stage of a sinker EDM burn — from breakdown to flushing and recovery — is covered in our article on sinker EDM and the dielectric.

EDM601 or EDM101: which one to take

	EDM601	EDM101
Base	Highly refined mineral oil, low aromatics	Synthetic
Best at	Sinker EDM, roughing to finishing	Wire EDM, ultra-fine sinker finishing
Flash point	102 °C (216 °F)	88 °C (190 °F)
Viscosity at 40 °C	2.3 mm²/s	2.6 mm²/s
Odour	Very low	Odourless
Shelf life, unopened	12 months	24 months

EDM601 is the default choice for a sinker EDM shop. One oil covers roughing, semi-finishing and finishing on steels, carbide and non-ferrous metals, so the tank does not have to change with the job. Its higher flash point gives more margin between the oil and the working temperature in the tank.

EDM101 is the choice when the finish is the point. It is a synthetic oil for oil-based wire EDM and for the last, finest passes on a sinker: very low aromatic content, no odour, good cooling and flushing, low electrode wear. It is made to order, so plan the purchase rather than buying it on the day the tank runs low.

What to look at in an EDM oil

Flash point. The oil sits next to hot sparks in an open tank. A higher flash point means a wider safety margin, which is why it matters more on large sinkers running high currents.
Viscosity. Thin oil gets into narrow gaps and deep cavities and carries debris out; too thin and it evaporates faster. Both of our oils sit in the low range, around 2–3 mm²/s.
Aromatic content and odour. This is where EDM oils differ most on the shop floor. Low aromatics mean less smell, less vapour and a better working environment around the machine.
Filterability and oxidation stability. An EDM oil lives as long as the filters can keep it clean. An oil that ages slowly and filters well needs changing less often.

Pail, drum or tote

The 5-gallon pail is for topping up and for a first trial on your own machine — it has the highest price per gallon. The 55-gallon drum is the working size for regular production and costs about 17% less per gallon than the pail. The 270-gallon tote saves on handling rather than on price: one delivery and one draw-off point instead of five drums. Before choosing a tote, check that you will use it up within the shelf life — about 23 gallons a month for EDM601 and 11 gallons a month for EDM101.

How to keep EDM oil in service longer

Use the filter media your machine maker recommends and change filters on schedule.
Keep the tank temperature steady so viscosity and spark conditions stay the same through the shift.
Let parts drain over the tank before you take them out — drag-out is a real part of consumption.
Watch colour, odour and haze. A clear oil that turns cloudy is telling you something.
Top up with the same oil, or with one confirmed as compatible.

What really drives the cost

Dielectric fluid price per drum is only part of the bill. How fast the oil evaporates, how long it filters clean and how often the tank has to be changed decide what it costs per month of running. A cheaper oil that has to be replaced twice as often is not cheaper.

FAQ

Looking for coolants, cutting oils or way oils? See all metalworking fluids.

What EDM oil does in the gap

How the oil behaves at each stage of a sinker EDM burn — from breakdown to flushing and recovery — is covered in our article on sinker EDM and the dielectric.

EDM601 or EDM101: which one to take

EDM601

EDM101

Base

Highly refined mineral oil, low aromatics

Synthetic

Best at

Sinker EDM, roughing to finishing

Wire EDM, ultra-fine sinker finishing

Flash point

102 °C (216 °F)

88 °C (190 °F)

Viscosity at 40 °C

2.3 mm²/s

2.6 mm²/s

Odour

Very low

Odourless

Shelf life, unopened

12 months

24 months

What to look at in an EDM oil

Flash point. The oil sits next to hot sparks in an open tank. A higher flash point means a wider safety margin, which is why it matters more on large sinkers running high currents.

Viscosity. Thin oil gets into narrow gaps and deep cavities and carries debris out; too thin and it evaporates faster. Both of our oils sit in the low range, around 2–3 mm²/s.

Aromatic content and odour. This is where EDM oils differ most on the shop floor. Low aromatics mean less smell, less vapour and a better working environment around the machine.

Filterability and oxidation stability. An EDM oil lives as long as the filters can keep it clean. An oil that ages slowly and filters well needs changing less often.

Pail, drum or tote

How to keep EDM oil in service longer

Use the filter media your machine maker recommends and change filters on schedule.

Keep the tank temperature steady so viscosity and spark conditions stay the same through the shift.

Let parts drain over the tank before you take them out — drag-out is a real part of consumption.

Watch colour, odour and haze. A clear oil that turns cloudy is telling you something.

Top up with the same oil, or with one confirmed as compatible.

EDM Fluids

What EDM oil does in the gap

EDM601 or EDM101: which one to take

What to look at in an EDM oil

Pail, drum or tote

How to keep EDM oil in service longer

What really drives the cost

FAQ

What EDM oil does in the gap

EDM601 or EDM101: which one to take

What to look at in an EDM oil

Pail, drum or tote

How to keep EDM oil in service longer

What really drives the cost

FAQ