Detail comparison of Sinker EDM vs Wire EDM machining

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Electrical Discharge Machining, or EDM, is a fascinating world of sparks and electricity that has revolutionized the machining industry. It allows for the creation of intricate, high-quality components that would be nearly impossible to make using traditional machining techniques. This remarkable technology is divided into two primary types: Sinker EDM and Wire EDM. Both techniques offer unique advantages, depending on the specific requirements of the project.

In this blog post, we will delve into the details of these two types of EDM machining, providing a comprehensive comparison of Sinker EDM vs Wire EDM. We aim to help you understand the differences, the advantages, and the ideal use-cases for both, enabling you to make informed decisions for your machining needs.

Whether you’re a seasoned industry professional, an engineer in need of precision parts, or simply curious about machining technologies, this article promises insightful knowledge. Let’s get started..

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What is Electric Discharge Machining (EDM)?

Electric Discharge Machining, commonly referred to as EDM, is a non-traditional machining method that uses electrical discharges or “sparks” to cut, shape, or form hard metals and other electrically conductive materials. Unlike conventional cutting tools, EDM does not make direct contact with the workpiece. Instead, it removes material by rapid, recurring electrical discharges between the tool and the workpiece in the presence of an insulating liquid medium.


History of EDM

This process was first developed in the mid-1940s for the purpose of removing broken tools and taps from aluminum castings. As time passed, this technology has evolved and today, EDM is widely used in the manufacturing industry for its precision, versatility, and ability to work with extremely hard materials.


Working process of EDM

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The working principle of EDM is relatively straightforward. The EDM tool, often made from copper or graphite, is connected to the power supply’s positive terminal, and the workpiece is connected to the negative terminal.

In the EDM process, an electrode (the cutting tool) and the workpiece are connected to a power supply. The power supply generates an electrical potential between the two parts. When the electrode is brought close to the workpiece, the electric field’s intensity increases, ionizing the dielectric fluid in the small gap, and allowing a minute spark to jump.

This spark produces intense heat, melting and vaporizing a tiny portion of the workpiece. The waste material is removed by continuously flushing the gap with dielectric fluid. The entire process occurs in a dielectric fluid environment, acting as a coolant and controlling the spark characteristics.

EDM is unique for its ability to cut hard, electrically conductive materials that could be challenging with other cutting methods. It’s particularly advantageous when handling complex shapes and thin walled configurations without inducing stress on the material.


Applications of EDM in Different Industries

The Electrical Discharge Machining (EDM) process has revolutionized numerous industries due to its capacity for precision machining of complex parts. In this section, we’ll explore the diverse applications of both Sinker EDM and Wire EDM in various industries.


Aerospace Industry

The aerospace industry requires components that are made with extreme precision and high-quality materials that can withstand harsh conditions. Both Sinker and Wire EDM offer the capability to produce complex shapes and work with tough materials like titanium and Inconel commonly used in aerospace.


Electronics Industry

Micro-component manufacturing is a vital part of the electronics industry. Wire EDM, particularly, is ideal for creating small and intricate components with high accuracy, which is crucial in producing semiconductor and circuitry components.


Military and Defense

The military and defense industry relies heavily on both types of EDM machining due to the need for durable and precise parts. This industry often requires work with hardened materials for the manufacturing of components like engine parts, firearm components, and more.


Medical Industry

The medical industry benefits immensely from EDM. Sinker EDM can be used to create molds for medical equipment and devices, while Wire EDM is utilized for precision cutting of micro-components for items like surgical tools and implants.


Agriculture, Lighting, and Automation

In agriculture, lighting, and automation industries, EDM provides solutions for a wide range of needs. From molds for agricultural tools and machinery to intricate lighting fixtures and components for automated systems, EDM has a wide range.

Understanding Sinker EDM (Die Sinking EDM)

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Sinker EDM, also known as die-sinking EDM, plunge EDM, or ram EDM, is a process that involves an electrode and workpiece submerged in an insulating liquid such as oil or dielectric fluid. A series of rapid recurring current discharges are passed between the electrode and workpiece, effectively eroding the material from the workpiece by a series of rapidly recurring electrical discharges.


How does Sinker EDM work?

To comprehend how sinker EDM works, think about it as a process of electrical erosion. The pre-machined electrode and the workpiece never make contact. They’re kept apart by a carefully controlled minute gap. The electrode is brought near the workpiece, and an electrical discharge occurs between them. This discharge creates a high-intensity spark that vaporizes the workpiece material in a very localized area.


How fast is Sinker EDM?

The speed depends largely on the size and type of electrode, the discharge energy, and the specific material being machined. However, it is typically slower than other machining processes, but it compensates for this with its ability to produce complex shapes with a high degree of accuracy.


When to Use Sinker EDM

Sinker EDM is particularly useful in the following scenarios:

Complex geometries: This method is ideal when you need to create complex shapes or cavities that would be difficult, if not impossible, to achieve with conventional machining methods.

Hard materials: If the workpiece is composed of a particularly hard material that is difficult to machine using traditional methods, sinker EDM comes in handy. The process does not depend on the hardness of the material, making it an excellent choice for such cases.

Thin materials: For thin workpieces that might deform under the mechanical stress of conventional machining, sinker EDM is a safer alternative due to its non-contact nature.


The make-up of a Sinker EDM machine

A Sinker EDM machine consists of the following main components:

Power Supply: This converts AC power to the low voltage DC power needed for the EDM process.

Electrode: This is the tool that is used to create the desired shape in the workpiece. It’s usually made of graphite or copper.

Dielectric Fluid System: The gap between the electrode and the workpiece is filled with a dielectric fluid. This system circulates, filters, and cools the fluid.

Control system: This is the ‘brain’ of the machine, controlling the movement of the electrode and managing the power supply to maintain optimal spark conditions.


Sinker EDM voltage and speed

Sinker EDM typically operates between 60 and 260 volts. The specific voltage used depends on several factors, including the type of material being machined and the desired speed and quality of the process.

The speed of sinker EDM machining varies depending on the material and the specific application. While it is generally slower than other machining processes, its ability to create precise, intricate geometries in hard materials often outweighs the speed considerations.


Advantages of Sinker EDM

Sinker EDM offers numerous advantages that make it a valuable addition to a manufacturer’s toolbox:

Versatility: It can machine any electrically conductive material, irrespective of hardness. This includes everything from aluminum to hardened steel and even exotic metals.

Complex geometries: Sinker EDM excels at creating intricate and complex 3D shapes that are impossible with traditional machining methods.

No direct contact: As a non-contact machining method, it eliminates the risk of tool wear and breakage. This also means that there is no induced mechanical or thermal stress on the workpiece, which is particularly advantageous when dealing with delicate or fragile parts.

Superior Surface Finish: Sinker EDM can produce a very high-quality surface finish, often eliminating the need for post-machining surface treatment.


Can you EDM sink aluminum?

Yes, you can EDM sink aluminum. Aluminum is an electrically conductive material, which makes it suitable for the EDM process. Due to its relatively low melting point and excellent thermal conductivity, it can be machined with great precision and minimal risk of distortion or damage. However, it’s worth noting that because of these properties, the machining parameters must be carefully controlled to prevent excessive electrode wear or poor surface finish.


How deep can you plunge with EDM?

The depth to which you can plunge with EDM is largely dependent on the type of electrode used and the specific machine setup. Generally, the depth can range from a few millimeters to several hundred millimeters. One of the advantages of EDM is that it can maintain consistent accuracy and precision, even at great depths. It’s worth noting, however, that deeper cuts will require more time and potentially more advanced electrodes.

For more information about EDM machining, particularly Sinker EDM, I recommend checking out our equipment page at Worthy Hardware. It contains useful details about the tools and techniques we use in our manufacturing process.

Please stay tuned for the next section where we’ll delve into Wire EDM machining, another vital process in the world of manufacturing.

Understanding Wire EDM

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Wire Electrical Discharge Machining (Wire EDM) is a process that uses a thin single-strand metal wire, typically brass, as the electrode. This method is commonly used for creating detailed profiles or cuts and is especially useful when high levels of accuracy are required.

The wire, which is continuously fed from a spool, is held between upper and lower diamond guides. The guides, which are CNC controlled, move in the X-Y plane, and sometimes the U-V plane, depending on the flexibility of the machine.


How Wire EDM works

Wire EDM works by creating a series of repetitive electrical discharges between the workpiece and the wire electrode, which is submerged in a tank of dielectric fluid. These discharges generate intense heat that melts and vaporizes a small portion of the workpiece, resulting in the cutting action.

The dielectric fluid helps in cooling and flushing away the material particles from the cutting area. The wire, which is continuously moving, ensures that the discharged area of the wire electrode does not contact the workpiece, thus allowing for a consistent cut.


When to use Wire EDM

Wire EDM is generally the method of choice when high precision is needed. This could include:

Creating intricate details: Due to its ability to use thin wire as an electrode, Wire EDM is ideal for cutting intricate shapes or detailed profiles that other machining methods would struggle with.

Working with hard materials: Just like Sinker EDM, Wire EDM is also excellent for working with hardened materials that are too tough for traditional machining.

Low tolerances: Wire EDM is an excellent option when you require low tolerances. With this technique, it is possible to achieve tolerances as low as 0.005 mm.


How accurate is a Wire Cut machine?

A Wire Cut machine can be incredibly accurate. The precision of the cuts is one of the standout features of Wire EDM, making it a preferred choice for industries such as aerospace and electronics where high accuracy is vital. A typical Wire Cut machine can achieve tolerances of +/- 0.005 mm, although this may vary based on the specific machine and the material being worked on.


How thick of material can you Wire EDM?

One of the striking features of Wire EDM is its ability to handle a variety of material thicknesses with high precision. Generally, it can accurately machine materials as thick as 300mm. However, the thickness that Wire EDM can handle largely depends on the type of machine used and the specific requirements of the project, such as the desired accuracy and finish.


Advantages of Wire EDM

Wire EDM presents several compelling advantages:

High Precision: Wire EDM provides a high level of accuracy and consistency, even on complex shapes or intricate cuts. This makes it a perfect choice for industries requiring tight tolerances.

No Contact: Just like Sinker EDM, Wire EDM is a non-contact machining process. This means there is no force exerted on the part during machining, reducing the risk of deformation or damage, especially when dealing with delicate parts.

Versatility: Wire EDM can cut intricate shapes and deep parts in any electrically conductive material, regardless of hardness. Materials that are difficult to machine with other methods, like titanium or carbide, can be cut efficiently and accurately with Wire EDM.

Fine Finishes: The Wire EDM process can deliver excellent surface finishes, often eliminating the need for additional post-machining surface treatments.

To get a better sense of the capabilities of Wire EDM and see how it fits into the manufacturing workflow, check out our CNC machining service at Worthy Hardware. The next section will focus on comparing Sinker EDM and Wire EDM, discussing when one might be preferred over the other.

Sinker EDM vs Wire EDM Machining Comparison

While both Sinker EDM and Wire EDM processes fall under the umbrella of Electrical Discharge Machining, they differ in several ways. This section aims to provide a detailed comparison between the two, including their method of operation, the materials they can handle, and their most suitable applications.


Method of Operation

Sinker EDM, also known as Ram EDM or Die-Sinker EDM, involves an electrode and workpiece submerged in an insulating liquid like oil or dielectric fluid. The electrode and workpiece do not make physical contact, but a spark is generated through the dielectric fluid, melting and vaporizing a small portion of the workpiece.

Wire EDM, or Wire-Cut EDM, on the other hand, involves a thin wire acting as the electrode. The wire, usually made from brass or stratified copper, is held between two diamond guides and moves in a carefully controlled pattern. As with Sinker EDM, a spark jumps the gap between the wire and the workpiece, but the spark is controlled along the wire path, cutting the workpiece.


Dielectric Liquid

Both Sinker EDM and Wire EDM require the use of a dielectric liquid, which acts as an insulator until the voltage reaches a point where a spark is formed. In Sinker EDM, the workpiece and the electrode are submerged in this dielectric liquid. When the electrical voltage between the electrode and the workpiece overcomes the dielectric fluid’s resistance, a spark jumps across the gap and removes a small piece of the workpiece.

In Wire EDM, the dielectric liquid also cools and lubricates the wire and flushes away the eroded particles. The constant replenishment of fresh dielectric fluid ensures optimal cutting conditions and promotes a higher quality cut.


Materials Used

Both Sinker EDM and Wire EDM can handle a wide range of materials, as long as they are electrically conductive. This includes metals like titanium, aluminum, steel, copper, and many alloys.

However, Sinker EDM is generally more suitable for machining harder metals that are difficult to cut through traditional machining processes. Wire EDM is preferred when the workpiece requires intricate details or fine cuts, especially in the production of stamping dies and molds.



Sinker EDM is better suited for creating complex shapes and molds, cavities, or intricate patterns, especially when the material is extremely hard or tough. It is widely used in the aerospace and automotive industries for manufacturing engine components, gears, and turbine blades.

Wire EDM shines when precision and detailing are crucial. The ability to make fine cuts makes it perfect for creating miniature parts, tools, and dies, especially for the electronics and medical industry.


Surface Finish

Sinker EDM usually leaves a textured surface, which might need additional finishing. The surface finish in Sinker EDM depends on the size of the electrode, power settings, and the flushing condition.

In contrast, Wire EDM often provides a better surface finish, as the constantly moving wire electrode minimizes the risk of over-burn, and results in a finer finish.



Generally speaking, Wire EDM may have a higher operational cost due to the continuous need for new wire during the machining process.

In contrast, the electrode in Sinker EDM is reusable, potentially reducing long-term costs. But it’s worth mentioning that the cost of creating complex electrodes for specific jobs can be quite high.


Production Time

The production time in EDM machining is largely dependent on the material thickness, the size of the cut, and the desired accuracy. While both EDM types are not typically chosen for their speed, Sinker EDM might require more time due to the potential need for multiple electrodes.

Wire EDM, with its continuous wire feed, can often be faster for cuts where a straight wire can be passed entirely through the component. The time difference becomes apparent when working on thicker and harder materials.


Complexity of Operation

Sinker EDM machining may require a more complex setup, especially when dealing with intricate and unique shapes, as a specific electrode has to be made. However, it excels at creating 3D shapes, undercuts, and cavities that are not possible with Wire EDM.

In contrast, Wire EDM is simpler to set up and can provide better accuracy for 2D cuts, especially with fine details, but it may have limitations when dealing with complex 3D parts.


Waste and Debris

Sinker EDM uses an electrode that gradually wears during the machining process. As a result, it might produce more waste compared to Wire EDM.

Wire EDM, on the other hand, uses a constantly fed wire that reduces the waste produced. Also, the wire EDM process generally provides better flushing, effectively removing the cut debris.


Machining Functionalities

Sinker EDM and Wire EDM offer different functionalities based on their nature. Sinker EDM is excellent for complex geometries, deep cavities, and intricate details that would be impossible or challenging to machine using conventional cutting tools. It’s also capable of producing molds, dies, and various three-dimensional objects.

On the other hand, Wire EDM is specifically designed for the production of 2D shapes and profiles, making it an excellent choice for cutting stamping dies, extrusion dies, or any other part requiring precise contours and minimal distortion. Its wire electrode can create fine holes and narrow slots that are challenging for other machining methods.



Wire EDM offers a slightly higher precision level due to its cutting process, which does not make physical contact with the workpiece, hence no tool wear. It can achieve tolerances as tight as +/- 0.005 mm.

While Sinker EDM also provides excellent precision, tool wear can occur because the electrode physically contacts the workpiece during the machining process. Nonetheless, it still achieves a high level of accuracy, with tolerances typically around +/- 0.01 mm.

Sinker EDM vs. Wire EDM: Which One to Use?

Choosing between Sinker EDM and Wire EDM depends on the specifics of your project, including the material, geometry of the part, and the level of precision required. Below, we compare these two EDM methods to help you make an informed decision.


Complexity and Geometry of the Part

If you’re dealing with 3D shapes or complex geometries, Sinker EDM would be the optimal choice. This is because the electrode in Sinker EDM can be custom shaped to create intricate forms in the workpiece, even with deep recesses.

Wire EDM, on the other hand, is the go-to option for 2D shapes. It excels in producing intricate profiles and precise cuts, making it ideal for applications like punch and die sets or precision gears.


Material Type and Hardness

Both Sinker EDM and Wire EDM can handle any electrically conductive material, irrespective of hardness. However, the decision between the two often depends on the specific properties of the material and the desired end result.

For instance, if your project involves aluminum and you’re wondering if you can EDM sink aluminum – the answer is yes. Sinker EDM, with its controlled process, can effectively machine aluminum, providing a smooth finish.

Similarly, both methods can handle hardened materials. At Worthy Hardware, our equipment list includes both types of EDM machines, making us versatile to handle various materials.


Tolerance and Surface Finish

Both methods offer high precision, but the choice between the two will again depend on your specific requirements. Wire EDM provides excellent surface finishes, often negating the need for additional finishing processes. With the help of Wire EDM, a surface finish as fine as Ra 0.1µm can be achieved.

Sinker EDM, while being highly accurate, might require secondary finishing, especially if a very smooth surface is required.



While Wire EDM may provide a slower machining speed compared to conventional machining methods, it’s often faster than Sinker EDM due to the continuous feeding of the wire electrode.

How Worthy Hardware Provides Solutions

At Worthy Hardware, we specialize in manufacturing and exporting CNC machining parts, including Sinker EDM and Wire EDM components. Our team, equipped with top-notch machinery and years of expertise, ensures that our products meet the highest quality standards.

We understand the diverse needs of various industries and work closely with our clients to provide customized solutions. Our competitive advantage lies in our ability to create prototypes swiftly and support production across a range of materials.

To learn more about our capabilities in CNC machining, CNC milling, CNC turning, and more, please visit our services page. For any inquiries, feel free to contact us. We’re here to make your project a reality.


Understanding the characteristics, strengths, and limitations of both Sinker EDM and Wire EDM is crucial for selecting the most appropriate machining method for your project. Both processes have their unique advantages and are suited to different tasks. Sinker EDM excels in producing complex and intricate shapes in any conductive material, whereas Wire EDM shines in tasks requiring high precision, excellent finish, and complex cut geometry.

For more information, or to discuss your specific project requirements, don’t hesitate to contact us today.