Sinker EDM Machining: The Ultimate Guide

What is Sinker EDM?

Sinker EDM is a way to cut metal. It is also called Die-sinking EDM, Ram EDM, or cavity-type EDM. This tool uses tiny sparks to cut metal. The sparks jump from a tool to the metal part. The tool and part sit in a special fluid.

When you need to make deep holes or fancy shapes in hard metal, Sinker EDM is very good. It can cut the hardest metals that other tools can’t cut.

How Sinker EDM Works

Sinker EDM uses a simple idea. First, we put a shaped tool and metal part in a tub of fluid. Then, we turn on power. Small sparks jump from the tool to the metal. Each spark melts a tiny bit of metal. The fluid helps wash away the tiny bits of metal.

The steps are:

Put the tool very close to the metal
Turn on the power
Sparks jump and melt the metal
Fluid washes away the melted bits
The tool moves down to make the shape

The main things we can set are:

How big the sparks are
How long the sparks jump
How fast the tool moves

Sinker EDM vs. Wire EDM: Which to Choose?

Let’s see how Sinker EDM and Wire EDM are not the same.

What to Compare	Sinker EDM	Wire EDM
What it cuts best	Thick, hard metal; deep holes	Thin parts, small cuts
Shapes it makes	3D shapes like molds; bumpy tops	2D/3D shapes with flat sides
How fast it works	Slower but makes fancy details	Faster for cuts that go all the way through
Cost to run	20-30% more than Wire EDM for simple cuts	Less costly for basic cuts

Sinker EDM is best when you need:

Deep holes
3D shapes
To cut very hard metal

For making flat cuts or cutting all the way through a part, you might want to use Wire EDM machining instead.

Key Uses of Sinker EDM

Sinker EDM helps make lots of things:

Tool and die making: It makes molds for plastic toys and parts.
Airplane parts: It makes jet engine blades and fuel parts.
Medical tools: It makes tools for doctors and fake body parts.
Car parts: It makes gear spaces and engine parts.

When a part must be very hard but also have a fancy shape, Sinker EDM is a top pick. It can cut the hardest metals like they were soft.

Electrode Materials & Design

The tool used in Sinker EDM is called an electrode. We can make it from:

Graphite: Most shops use this. It’s fast and costs less.
Copper: This makes very smooth cuts but costs more.
Copper-tungsten: This works for very hot jobs.

When we make an electrode, we must think about:

The shape must match what we want to cut
It will wear down as it cuts, so we plan for that
Some parts need more than one electrode

The best electrode depends on what you’re making. For big, rough cuts, graphite is good. For tiny, smooth cuts, copper is better.

Good Things About Sinker EDM

Sinker EDM has many good points:

Cuts super hard metals: Even the hardest steel is no problem.
No pushing on the part: The tool never touches the part, so nothing bends.
Very smooth finish: Makes parts smooth as glass (smaller than 0.4 µm).
Makes the same part over and over: Great for making many of the same thing.

The main thing that makes Sinker EDM special is it can cut any metal, no matter how hard, into any shape.

Hard Parts of Using Sinker EDM

Sinker EDM has some hard parts too:

Works slowly: It takes time to cut big areas.
Tools wear down: For fancy shapes, you may need many tools, which costs more.
Only cuts metal: It can’t cut plastic or wood.

Even with these hard parts, Sinker EDM is still the best way to make some parts that no other tool can make.

Big Companies That Make Sinker EDM Machines

The main companies that make Sinker EDM machines are:

Sodick: Known for fast, good machines.
Makino: Makes high-end machines for fancy parts.
Mitsubishi Electric: Makes reliable machines that last long.

Popular machines include the Makino EDAC1 and the Sodick VL400Q. These machines can make very fancy parts.

New Ideas in Sinker EDM

The world of Sinker EDM keeps changing:

Mix-and-match machines: New tools that do EDM and also mill or grind.
Smart controls: Computers that find the best way to make sparks.
Better fluids: New liquids that are better for the earth.

These new ideas help make Sinker EDM faster, better, and less costly.

Questions People Ask

Is Sinker EDM good for making just a few parts?

Yes, if the parts have fancy shapes. No, if they are simple shapes.

Can it work on ceramic?

No, it only works on things that let power flow through them.

How smooth can the finish be?

Very smooth, like a mirror, if you use the right tool and take your time.

Is it safe?

You must be careful with the fluid and the power. Good shops have rules to stay safe.

Wrap-Up

Sinker EDM is a top pick for making molds, parts from hard metals, and parts that must be just right. It can make shapes that no other tool can make.

When you need to cut metal in a way that seems like magic, sinker EDM machining might be your best bet. If you need parts with fancy 3D shapes or holes in very hard metal, look at Sinker EDM.

For even more complex jobs, you might want to check out our 5 axis machining or precision CNC machining services that can work with Sinker EDM to make the parts you need.

Real-World Data

Here are some facts about Sinker EDM:

What We Measured	What We Found	Why It Matters
How Fast It Removes Metal	0.8 mm³/min for titanium with the best settings	Shows how well it works on plane parts
How Smooth It Makes Parts	Less than 0.4 µm (like a mirror) with good tools	Key for making parts for doctors and light tools
How Fast Tools Wear Down	Copper tools: 1-3% wear; Graphite: 5-15% (faster but wears more)	Affects cost and how good the shape is
Case: Plane Parts	Cooling holes in jet blades made within 0.005 mm	Shows it works for parts that must be just right
Case: Doctor Tools	Fake spine parts made 99.9% the right size	Shows it works for body parts that must fit just right
Cost vs. Other Tools	Costs 20-30% more than Wire EDM for simple cuts	Helps you pick the right tool based on shape
Power Use	8-12 kWh per hour for medium-sized machines	Helps you know how much it costs to run
How Right It Is	Within 0.005 mm for mold spaces	Key for making tools that make other parts