Electrical discharge cutting (EDM) is a non-traditional subtractive manufacturing process that uses electrical energy in the form of sparks to cut or remove portions of a workpiece. The two common forms of this machining technology are punching and wire cutting.
This article provides a detailed comparison between die sinking and wire EDM, examining the advantages, disadvantages, applications and differences.
Die Sink EDM Overview
Sinker EDM is a type of electrical discharge machining in which an electrode and workpiece are immersed in an insulating fluid, usually a hydrocarbon oil or other dielectric fluid. It is sometimes called ram, cavity, or volume EDM. The machining process uses prefabricated electrodes – copper, graphite or tungsten – to form a “positive” of the desired shape. The electrodes are then pressed against the workpiece to create the negative of the material's actual shape.
The most important factors that determine the choice of electrode for sinking are the resistance and conductivity of the electrodes. For example, graphite electrodes are easier to machine compared to copper. However, copper has higher conductivity.
Die sinking is the process of creating complex structures in a workpiece using a positive copy of the desired shape. For example, if a drawing requires a pyramid shape, the selected editing tool will have a similar shape – a pyramid. This is a clear difference from other machining technologies, where cutting tools cut along different axes to produce the desired shape. Because of this difference, penetration EDM can be time-consuming because the machinist must machine the cutting tool before making the structure.
Advantages and Disadvantages of Sinking EDM
Let's briefly examine the advantages and disadvantages of die sinking EDM
Per
- Accuracy : Sinker EDM is suitable for precise machining and produces extremely precise details.
- Toolmaking : In contrast to other machining processes, die penetration EDM does not require a tool that is harder than the workpiece.
- shape : The process is suitable for creating complex shapes and devices, including irregularly shaped blind holes.
- Risk : It is a low-risk editing process.
- Metal type : If the metal is conductive, sink EDM is suitable for processing.
- Low voltage machining : Unlike aluminum machining, die sink EDM does not create any stress that could deform the cutting tool or workpiece.
- Complex Structures : As it does not necessarily cut the part unless necessary, it is suitable for making thin walls, blind holes, cross sections, etc.
Disadvantages
- Materials restriction : Sinker EDM is only suitable for processing conductive materials. The process is therefore unsuitable for plastics and composite materials.
- High energy consumption : Compared to CNC machines, the process consumes a lot of energy. A large amount of electricity is required to generate enough energy for the process.
- Time : The process is more expensive and time-consuming than traditional machining methods.
Sink EDM Applications
As already mentioned, die sinking is suitable for creating complex cavities. The process is typically suitable for producing hard tools such as molds and dies, as well as creating deep ribs. Typical sink EDM application includes the following:
- Construction of dies and molds
- Rapid tool deployment
- Sharp inner corners
- Thin and deep ribs
- injection molds
- Fine details
- Medical parts and devices
- Blind keys
- matters
- Creating complex designs in jewelry and precious metals
- Internal gear etc.
Wire EDM Overview
Wire EDM is another form of electrical discharge machining. It is a non-contact machining process that uses thin, single-core metal wire, electrically charged with a suitable dielectric fluid to cut a part into the desired shape. It is sometimes called spark EDM, wire EDM, or simply wire EDM. As with penetration EDM, workpieces must be good conductors of electricity, such as metals and graphite. However, the dielectric fluid is usually deionized water.
This process does not necessarily cut the metal parts. Instead, a thin wire is used to create precise cutting lines by melting or vaporizing the metal until the wire completely penetrates the workpiece. Therefore, the process may be better suited to machining parts that challenge traditional machining techniques, as long as the part is conductive.
The components of a typical wire EDM include the CNC tool, power source, dielectric, electrodes, and of course cutting wires, which can be made of brass, diffusion annealed, or galvanized wires. The process is suitable for cutting aluminum, graphite and brass, but also harder metals such as steel and titanium.
Advantages and disadvantages of wire EDM
Per
- Continuous processing : The editing process is continuous. Even if the thread breaks, the process continues almost immediately with little or no interruption.
- High Precision Cutting : Wire EDM creates highly precise and precise parts. They are suitable for producing structures with complex geometries and tight tolerances that challenge traditional machining processes.
- Versatility : Wire EDM is very versatile. The process is suitable for cutting various materials (conductors), including aluminum, steel, tungsten, brass, graphite and titanium.
- Does not leave stains : It is a one-step process without deformations or burrs on the piece.
Disadvantages
- Significant limitations : It is only suitable for materials that can conduct electricity.
- Additional finishing may be required. : After cutting metal parts, an oxide layer may form on the surfaces, which requires expensive post-processing and finishing.
- Cost : A wire EDM machine requires high purchase costs. Maintenance is also quite expensive.
Wire EDM Applications
As mentioned previously, wire EDM produces parts with tight tolerances, high precision and dimensional accuracy. Below you will find typical applications of this processing method.
- Automobile industry : Cars and other motor vehicles have many complex parts that require high-precision machining. Wire EDM is suitable for the production of engine cylinders, gears and transmissions, fuel injectors and other components.
- Electronic parts : Microcomponents for electrical devices can be manufactured using wire EDM. These components include sensors, microchips, connectors, etc.
- Aerospace : The aerospace industry uses wire EDM to produce parts that require high precision and dimensional accuracy. This process can be used to produce turbine blades, chassis parts and guide vanes.
- Medical Products : Wire EDM is suitable for manufacturing surgical implants, prosthetics and other medical devices.
- Mold, Tool, and Die Production : Wire EDM can be used to create dies and shapes for various manufacturing processes, including injection molding, blow molding, die casting, etc.
Sinker EDM vs. Wire EDM: What are the differences?
Sinker EDM and Wire EDM have some similarities as they are both electrical discharge machining. However, there are also clear differences that set them apart. That includes:
cutting process
During die sink EDM, sparks are created between the workpiece and the material during cutting, which vaporize or melt the metal parts. Sinker EDM uses a thin wire to create electrical sparks that vaporize or corrode metal.
Dielectric fluid
While sinking tends to use hydrocarbon oils, wire cutting often uses deionized water as the dielectric.
electrode wire
Sinker EDM uses a custom electrode that resembles the 3D profile or shape of the desired product. This is then lowered into the workpiece to cut the shape. However, wire EDM uses essentially the same thin electrical wire that passes through the material and cuts it into the desired structure.
Processing speed
Unlike die sinking, the machinist must first create a custom die for manufacturing, especially for complex structures. Wire EDM uses a simple, thin, thread-like wire to cut. This makes wire EDM a faster and cheaper manufacturing method.
Editing functions
Die sinking EDM is more suitable for 3D contouring, drilling, deburring, finishing, etc. On the other hand, wired EDM is available for 2D cutting and high-precision profile cutting as well as sample preparation.
While with wire EDM machining can only start at the edges of a workpiece, with sink EDM machining it can start from anywhere, even if the workpiece has no holes or edges. This makes penetration EDM more suitable for creating cavities or holes that were not originally present at the bottom of the material.
precision
In fact, both EDM processes produce accurate and precise cuts. Wire EDM is best suited for parts with strict accuracy and tolerance requirements.
How to choose between sinker EDM and wire EDM?
Although we have shown the difference between wired EDM and sinker EDM, you will agree that they are similar. After all, both are types of spark erosion. However, which one should you choose for your manufacturing?
Let's keep it simple: Choosing a method should depend on your manufacturing needs. For example, wire EDM is suitable for smaller production runs with high-precision patterns. However, die sinking is best suited for creating dies and shapes for injection molding and other manufacturing processes.
Before deciding which method to choose for your project, consider the following.
- Surface Finish : Wire EDM leaves a smoother, finer surface, while sink EDM may leave the surface a little rougher.
- Material Type and Thickness : Choose die sink for stiffer, stronger materials such as steel and titanium. Wire EDM is best for thinner materials.
- Production costs : If you are on a limited budget, opt for wire EDM, it is cheaper.
- Part geometry and shape : Sinker EDM is preferred for molds, dies, and deep cavities with complex shapes.
- Series production : Wire EDM is a faster manufacturing process. Therefore, it is the best choice for large production volumes.
WayKen: Your partner for EDM services
EDM is a valuable manufacturing technique suitable for diverse applications. However, in addition to understanding the different types and their specifics, you need to work with an expert to ensure top-notch EDM services for your manufacturing.
Concluding
Sinker EDM and wire EDM are two unconventional machining processes. However, both are widely used in industry for various applications. Knowing the similarities, advantages and disadvantages of the two processes will help you decide which process is best for your manufacturing needs.
Common questions
What three types of EDM exist?
The three types of electrical discharge machining include die sinking, wire EDM, and drilling. What all three manufacturing processes have in common is that they use electrical currents to cut metal parts.
What is the difference between EDM and ECM?
EDM – Electrical Discharge Machining – uses electrical discharge, current or sparks to cut or remove pieces of material. ECM – electrochemical machining – on the other hand, uses electrolysis (chemical reaction) to dissolve or corrode pieces of material (metal).
What is the main similarity between penetration EDM and wire EDM?
The main similarity between die sinking and wire EDM is that both processes use electrical current or sparks to cut or remove material from a part until the desired shape is achieved. Furthermore, both methods use an electrode to cut the metal and a dielectric fluid that acts as an insulator.
