Die Sinking EDM Overview

Posted on May 17, 2021

Die Sinking EDM

The materials that are not electrically conductive, such as high-nickel alloys or carbide materials are the restriction in the application of die-sinking EDM. In order to deal with this problem, the manufacturer may replace the material of the electrode, so that the electrode and the workpiece can interact with each other without challenge, but that may result in a longer working time than those electrically conductive workpieces.

Die sinking EDM, also known as sinker EDM, cavity type EDM, or volume EDM is a type of machining that mainly produces dies or molds with the interaction between the electrode and the workpiece. EDM stands for electrical discharge machining. The similarity between EDM and other machining methods is in the power source, as they are all powered by electricity. While the main difference is that most of the machining methods require the tools to come in contact with the workpieces, EDM does not.

The machining process that follows the die-sinking electrical discharge machining separates the working tool (the electrode) from the workpiece by submerging it into insulating liquid, such as hydrocarbon oil or other dielectric fluids. With the electrical potential that is generated by the power supply, the electrode approaches the workpiece, and then the electric voltage will be discharged and the spark will jump, which results in the desired shapes to be made.

Die sinking EDM benefits the tooling industries, as they are capable of producing dies and molds with smooth finishes and are formed by intricate shapes. These dies and molds can be further applied in other machining works, which shows the versatility of die-sinking EDM since it acts as the source of more precision machining works in fields. In addition, because the electrode and the workpieces never come in contact with each other, the die-sinking EDM is suitable and perfect not only for the hardened materials and exotic alloys but for the delicate or thin materials.
 

How does die-sinking EDM work?

A die-sinking EDM consists of two parts, including an electrode and the workpiece that is immersed into the liquid. The two parts are set separately when the machine is operated. The electrodes in die-sinking EDM are connected to a power supply. The power supply turns on and off automatically based on the parameters that are set on the controller. When the power source is on, the electricity facilitates the approach from the electrode to the workpiece. Once the electrode and the workpiece are put close to about one inch, the process starts.

The working principle of die-sinking EDM is using the heat transferred from the electricity to burn the electrode to melt the workpieces, which is either metal or plastic. It is able to work with CNC technology, which creates the program that instructs the making of the desired pattern and follows the instruction to make the dies or molds.

When the electrode and the workpiece are close enough, the electric voltage will be discharged and the spark will jump. Several hundred thousand sparks jump out one after another within seconds. The shape of the electrode will then be formed opposite to the cavity in the die or mold. When the sparks are made, the electrodes gradually form the shape of the cavity by the heat of the sparks.

The base of the material is eroded, the spark gap subsequently increases, and the electrode is lowered automatically by the machine so that the process can continue without interruption. After the shape of the die or mold is formed on the material of the workpiece, the work of die-sinking EDM is finished.
 

:: Read More: What Are Some Advanced Applications of EDM Cutting Machines?
 

What is so special about die-sinking EDM?


non-contact operation

Unlike drilling and milling processes, die-sinking EDM allows the working tool and the workpiece not to contact each other. This feature makes die-sinking EDM suitable for fragile and delicate materials and avoids damage to the material, which is what other conventional working tools cannot achieve.
 

versatility

Since die-sinking EDM is operated by the sparks that are made by the electricity instead of the force and shapes of other conventional working tools, the shapes that die-sinking EDM can form are broader, and the force of the sparks are not limited by the foxed tools.

In addition to die-sinking EDM that produces dies and molds, other types of EDM are applied for other purposes. Furthermore, because the force of the operation is not limited by the fixed working tools, the sparks controlled by the amount of electric voltage can also work for extremely hard materials, which shows the versatility of the die-sinking EDM.
 

overheating prevention

Another special feature of die-sinking EDM is that, since the electrodes and the workpiece are submerged into the hydrocarbon oil or other dielectric fluids, the operation is protected by the liquids, so as to prevent the working parts and the materials from being overheated.
 

smooth finishes can be achieved

When the die-sinking EDM is operated, the superimposed movements of X, Y, C, and Z axes can create the cavities inside the dies or molds with smooth finishes, and thus allows for a wider range of applications. In contrast, other conventional machining works usually operate by up to three axes, which are X, Y, Z respectively, so they are not able to make smooth finishes as the movements are restricted by the axes.
 

smaller and deeper holes can be made

The non-contact feature should be definitely credited to this achievement. Since the die-sinking EDM allows the electrode of the workpiece to retain some space between them, the two parts would not contact each other, and the excessive diameter of the holes that may have occurred by the grinding of the contacting surfaces can be avoided.

Thanks to this extraordinary feature of die-sinking EDM, smaller and deeper holes can be made without being flared by other working tools. The manufacturing of parts that require more sophisticated precision can be ensured.
 

What concerns there might be when adopting die-sinking EDM?

According to the principle in the operation of die-sinking EDM, the workpiece that the machine works for must be electrically conductive, which makes it limited in the materials that can be applied.

The materials that are not electrically conductive, such as high-nickel alloys or carbide materials are the restriction in the application of die-sinking EDM. In order to deal with this problem, the manufacturer may replace the material of the electrode, so that the electrode and the workpiece can interact with each other without challenge, but that may result in a longer working time than those electrically conductive workpieces.

What's more, since the cavities of the dies and molds that are produced by die-sinking EDM rely on the heat of the sparks, there might be some influence of the heat in the areas that are not supposed to be acted to, while this is the problem that does not happen all the time.
 

IMTS Exhibition

IMTS gathered worldwide Sinker EDM manufacturers into this online platform. Browse and search for your next supplier with us.

Should you run into any difficulties, please do not hesitate to contact us.

Quick Link to Suppliers

0Inquiry Item Contact IMTS