Wire EDM or Electrical Discharge Machining is an old but efficient way of making complicated parts. The technique is especially effective when used on any electrically conductive material including hard-wearing alloys such as titanium, tool steel, and stainless steel. Wire cut machining is considered among the most common types of EDMs together with fast hole drilling and sinker EDM that involves the use of a wire electrode to cut the required shape using electrical sparks. These sparks shape the metal in the form of cuts and shapes through a guiding wire. The following wire(electrode) is fed between two spools rotates and avoids wearing out. This article focuses on the unmatched capabilities of Wire cut machining in terms of accuracy and flexibility, and its importance in manufacturing challenging, high-accuracy parts.

Key Components of a Wire EDM Machine

A Wire EDM machine consists of several important parts, instrumental in cutting and shaping the materials. Let’s look at each component and its functioning;

CNC Tools

CNC tools are involved in the Wire EDM process to determine the path of and also help control the cutting process. Moreover, it regulates the feed of the wire, the tension, and electrical sparks in the wire cut process.

Power Supply

The power supply unit sends electrical pulses to the wire electrode and the workpiece through the wire electrode. These pulses vary from 100V to 300V. It controls the charge density, frequency, and charge intensity, required for accurate material interaction.

Wire

The wire acts as the electrode used in producing electrical discharge. The most frequently used wires are categories like; brass, zinc-coated, and diffusion-annealed. These are available in different diameters ranging from 0.05 to 0.25mm, approximately.

Dielectric Medium

Deionized water serves as dielectric fluid to avoid the formation of particles on the wire as well as to cool the process.

Electrodes

In the Wire EDM process, the wire electrode acts as a cathode, while the anode is the workpiece rotated by a servo motor. Moreover, the servo motor ensures that the wire does not come into contact with the workpiece to preserve part quality.

Ways and Techniques of Wire Cut Machining

Wire EDM Cutting Process

Wire EDM cutting utilizes a thin and single-strand metal wire—brass or copper most often—as the cutting tool to cut through the conductive materials. Here's how it works:

Wire and Dielectric Fluid Interaction

Electrodes in the form of a wire traverse through the workpiece placed in a tank containing dielectric fluid which is usually deionized water. This fluid isolates the wire from the workpiece and also aids in the removal of debris produced during cutting. 

Electrical Discharge Process

The wire is attached to one of the negative terminals, and the workpiece is connected to one of the positive terminals. A high voltage is applied across the small gap between them which causes the creation of an electrical field. When this voltage is reached at a certain level(desired), sparks are formed and they arc across the gap. As a result, tiny metal fragments are vaporized.

Cutting Mechanism

These sparks either melt the material or wear it down along the path of the wire. So, the wire can shave off material from the workpiece without coming into direct contact with it. In the case of a CNC system, the wire is led along the X and Y axes as a band saw to develop the required shape.

Wire and Workpiece Alignment

A servomechanism regulates a constant distance between the wire and the workpiece along the programmed path. The deionized water constantly passes through this space cleans and cools the wire making Wire EDM able to create more precise and intricate cuts.

omparing Wire Cut EDM and Conventional EDM

The table below highlights the differences between Wire EDM and Conventional EDM in terms of accuracy, surface quality, cutting speed, material thickness, and electrode wear.

Metals Suitable for Wire EDM Machining

Wire EDM is favorable in cutting a variety of electrically conductive metals, usually, those, difficult to cut through normal machining. Suitable metals include:

• Aluminum
• Titanium
• Steel
• Brass
• Carbides (Tungsten, Silicon, Boron)

Pros & Cons of Wire Cutting EDM

Let’s compare the benefits, and drawbacks of wire cutting EDM process;

Pros of Wire EDM

• Wire EDM cutting is exceptionally accurate hence most of the materials that go through wire EDM do not require further finishing.
• Can make intricate designs and shapes, challenging to make by traditional means of CNC technologies.
• EDM cutting proves to be useful when working with small intricate parts and using materials that cannot withstand other forms of machining pressure.
• It can trims materials in a single operation, thus reducing burrs and distortion.

 Cons of Wire EDM

• Wire EDM applies to only conductive metals, and is limited to suppose only fever one.
• Some of them such as aluminum may have an oxide layer on the cut surface that may need further polishing and therefore may lead to high costs.
• The initial cost of installation of Wire EDM machines, and costs of maintenance are somewhat high.

3 types of EDM machining & Their Difference:

Here are three commonly used machines for wire edm machining;

Wire Cut EDM

Wire Cut EDM uses a form of a thin wire that oscillates to the machine through the material by removing it through spark discharge. Ideal for producing intricate 2D and 3D shapes with high dimensional accuracy. This method is widely applied in the creation of tools for extrusion and punch/die sets. 

Sinker EDM

Sinker EDM is also referred to as Ram EDM or a type of edm machining service. It employs an electrode to force its way into the workpiece, while the electrode has the desired shape of the cavity to be machined. The electrode is inserted into the material and then cut into very thin sections without applying any pressure on it. In most cases, it is used in mold and die-making industries because of the fine details of the cavity.

Hole Drilling EDM

Hole Drilling EDM is also used for micro-hole making with a high aspect ratio. It mainly employs a straight electrode to make holes of any depth with close tolerances held on the diameter of the electrode. Moreover, it's useful when there is a requirement to make through holes of great depth and accuracy in the material which could otherwise be regarded as ‘impossible’.

Applications of Wire Cut EDM

Wire cut machining is widely used in various industries because of its accuracy and the possibility of manufacturing complex parts.

Summary

Wire cut machining is an accurate process of cutting intricate shapes and is mostly applied in aerospace and medical sectors, where small interferences are crucial. Moreover, it is notably used in prototypes and when producing custom parts. When it comes to applications that require the highest level of accuracy, speed, and consistency, Wire EDM isn’t a simple choice, but a must process to opt for. If you are looking for fine detailing, and tight tolerances in your part machining project, then you should turn to reliable wire edm services as a solution.

FAQ’s

Q1. How accurate is Wire Cutting EDM?

Wire EDM machines can work with an accuracy of up to 0.0025mm with a surface quality of up to 1.5 Ra, depending on the machine setting, and the set parameters. It also enables the cutting of complex profiles with narrow tolerances within a short time.

Q2. EDM vs.  Laser Cutting: Which approach is better?

EDM machining is suitable for making accurate and intricate patterns on, and limited to conductive material with high precision. Conversely, laser cutting is useful in making designs on conductive material within a shorter duration and also applies to plastic polymers.

Q3. Why is deionized water needed in Wire Cut EDM?

The use of deionized water is essential for cooling the wire and for cleaning during the cutting. Because it lacks ions to ensure the highest possible accuracy and stability of electrical discharge conditions.

Q4. Is Wire EDM appropriate for large-scale production?

Wire EDM is suitable for large-scale production. It is suitable for making complicated parts in big lots without any compromise on part quality.

Q5. What kind of material can not be cut by using Wire EDM?

Wire EDM cannot be applied to non-conductive materials such as ceramics, glass, and most of the plastic materials. The method can only be applied to electrically conductive material.