In manufacturing, wire-cutting machine tools are gradually being widely used. They are known for their high-precision cutting. WEDM is advanced equipment. It uses a fine metal wire (electrode wire) as a tool electrode. It passes a pulse current between the wire and the workpiece. It cuts the workpiece using the electrocorrosive effect of the pulse discharge. It breaks the limits of traditional methods. It can process complex and precise workpieces. This article will take you together to explore the processing principle of wire-cutting machine tools, machine types. The types of materials it can cut and their characteristics. The advantages and limitations of using it to process materials. Its applications and machining techniques in processing different materials. By understanding these, it can help us see more clearly. It shows the key role of wire-cutting in modern manufacturing.
Table of Contents
What is wire-cut electrical discharge machining?
Wire Cut Electrical Discharge Machining (WEDM), also known as Wire EDM, is a special kind of machining. Its basic principle is to use a moving thin metal wire (an electrode wire) to pulse spark discharge on the workpiece. This melts and vaporizes the workpiece material, cutting it.
How does wire EDM work?
The working principle of WEDM is based on the phenomenon of electric spark discharge. In the process, the electrode wire and the workpiece connect to the positive and negative poles of the power supply. When they are close to a certain distance, an electric field forms in the working fluid (usually deionized water or other insulating liquid). The electric field strength increases. This makes sparks form between the workpiece and the electrode wire at the discharge voltage. The spark’s heat melts and vaporizes the workpiece. The blast then washes away the melted material. This process removes material.
Types of WEDM machines
To understand the types of WEDM machines, you must first know that they can be classified by different criteria. For example, by type of traveler, field of use, or form of construction. The following are some common types of WEDM machines:
Classification by type of wire traveler
A fast-traveling wire-cutting machine is one in which the electrode wire runs at a faster speed. It usually uses molybdenum wire as the electrode wire. Its processing precision and surface quality are relatively low, but the processing cost is also low, and it is suitable for the processing of parts that do not require too high precision. The slow-feeding wire-cutting machine tool is relatively slow to run the electrode wire, usually using copper wire. Processing precision is high, surface quality is good, but the processing cost is higher, commonly used in processing high-precision, complex shape parts.
Divided by application field
An ordinary wire-cutting machine uses conventional electrical discharge machining. It usually uses fast-wire technology. It applies to the processing of general industrial parts, such as mechanical parts, molds and so on. It is different from the precision wire cutting machine tool. It uses advanced electrical discharge machining. It has high stability and high control accuracy. Usually use slow-feeding wire technology.
Divided by structural form
According to the structure form can be divided into vertical wire cutting machine tools and bedroom wire cutting machine tools. The former is mainly the spindle perpendicular to the worktable, and the workpiece is placed horizontally. Suitable for processing small and medium-sized parts, easy to observe and operate. The latter is that the spindle is parallel to the table surface and the workpiece is placed horizontally or inclined. It is mainly suitable for processing large parts and shaped parts.
What are the materials suitable for WEDM?
One of the most critical factors in using wire EDM is that the material must be electrically conductive. Good conductivity ensures that the current flows smoothly. This results in a stable discharge pulse that removes material efficiently and precisely. Only if the processed material has good electrical conductivity can the parts be processed using WEDM. Selection of the right material for wire EDM processing is therefore crucial for the quality of the final part.
Metal materials
Metal materials in general have good electrical conductivity and are widely used in the field of mechanical engineering. Therefore, wire EDM is more friendly to the processing of metal materials. For example, steel (including carbon steel, alloy steel, etc.), stainless steel, carbide, titanium and titanium alloys and other metal materials. Tungsten steel and tungsten carbide in cemented carbide. These materials are hard and wear-resistant. They are good for making high-precision molds and tools using wire EDM. High-temperature alloys are common in aircraft engines and turbines. They can keep good strength in high heat.
Non-metallic materials
Wire EDM mainly processes conductive materials. Through special techniques, it can also process non-metallic materials like graphite and ceramics. Graphite itself is electrically conductive and can therefore be processed directly using Wire EDM. Ceramic materials, however, are usually not electrically conductive and the process is therefore slightly more complex. Before machining, the ceramic surface is coated with a thin layer of electrically conductive material such as copper or silver plating. Alternatively, special conductive fixtures can be used. They hold and support the ceramic workpiece. They ensure that current can pass through it during machining. You can also immerse the ceramic in a working fluid with conductive particles. This gives it temporary conductive properties. These can be used with suitable electrode wires for the cutting process of ceramic materials.
Special materials
Some new composite materials can also be processed by wire cutting. These include metal matrix and carbon fiber composites. But, this is only possible under special conditions. The metal in the metal matrix composite must be well distributed. It must also have good electrical conductivity. Then, wire cutting can be done. The machinability of metal matrix composites depends mainly on their microstructure and the nature of the constituent phases. Carbon fiber reinforced composites can also be processed using wire-cutting discharge, but generally do not use, usually using other more suitable processing methods, such as mechanical processing, laser processing and so on.
Advantages of wire-cut electrical discharge processing
Compared with other processing methods, wire EDM has the following advantages:
- High precision:Wire-cut electrical discharge machining can realize high machining precision, especially for complex shapes and tiny-sized parts, which has significant advantages. It can also realize a very good surface finish. To achieve the best surface finish in EDM, attention needs to be paid to electrical parameter optimization, electrode material selection, machining fluid selection, high-frequency vibration technology, precision servo control, and appropriate surface post-treatment. Through the application of these technologies, surface finish can be significantly improved to meet the machining requirements of high-precision parts.
- Processing a wide range of conductive materials:As long as the conductive material, regardless of the thickness, size, and hardness of the material, can be processed. It is suitable for all kinds of hardness materials, including cemented carbide, ceramics, metals, etc., and has strong adaptability.
- Suitable for machining parts with complex shapes:Wire-cut machining can process complex CNC curves. It can handle flexible shapes, like a mix of straight lines and arcs. It can even handle taper by moving the upper and lower lines.
- Does not produce mechanical stress:Machining has no cutting force. It has less impact and heat on the workpiece. It is good for thin-walled parts and brittle materials. It reduces workpiece deformation and stress.
Limitations of wire-cut machining
Although there are many processing advantages of wire cutting processing, it also has certain limitations. The disadvantages are as follows:
- Processing speed is relatively slow. Wire cutting is fast. But, for thick and hard materials, it’s slower than other methods. It is suitable for precision machining and small batch production, and is not suitable for large-volume rapid machining.
- Processing range is limited. Wire cutting can only process conductive materials, for non-conductive materials such as plastics, rubber, etc. can not be processed.
- Frequent replacement of electrode wire. Electrode wire in the process of processing will continue to consume, non-stop corrosion by the electric spark, easy to break, so the need for frequent replacement of the electrode wire, increasing the cost of processing.
Common applications of wire-cut processing
Wire-cut processing is widely used in many industrial fields with its material characteristics of high precision and complex shape processing capability.
Mold Manufacturing
As molds require high precision, and many molds are processed with metal as raw material with high accuracy and ability to process complex shapes, wire-cutting processing is widely used in the field of mold manufacturing, such as injection molds, stamping molds, die-casting molds, and extrusion molds. It can accurately process complex cavities, cores, and shaped structures to ensure the precision and quality of molds. For mold manufacturing, wire EDM is one of the best processing methods for mold manufacturing.
Aerospace field
The parts used in aviation and aerospace fields require high precision, reliability and safety, because a tiny size machining defect may lead to serious disaster. Therefore, the use of wire EDM can maximize the design requirements and improve high precision. Used for processing aircraft engine blades, spacecraft parts, etc., the use of wire-cut electric discharge machining can meet the requirements of its high precision and complex shape.
Manufacture of electronic products
Nowadays, society is rapidly developing. Electronic products are getting more popular. The requirements for their functionality and performance are getting higher. In the electronics industry, wire cutting can process all kinds of electronic connectors, connectors and other precision parts.
Medical equipment manufacturing
In medical device manufacturing, wire-cut electrical discharge machining is used to manufacture high-precision surgical instruments, implants, dental tools and so on.
Automobile Manufacturing
In the field of automobile manufacturing, wire-cut electrical discharge machining is mainly used in the processing of automobile molds, engine parts, transmission system parts and so on.
Precision instruments and equipment
Many precision instruments on the parts of the tolerance requirements are relatively strict, the size of the parts are not particularly large, so wire-cut electrical discharge machining in the manufacture of precision instruments and equipment parts play an important role, such as optical instruments, medical equipment, measuring instruments, etc., there are a wide range of applications, can be processed tiny parts and high-precision components and to provide a good surface finish.
Tips for using wire-cut machining
WEDM is a high-precision machining method suitable for manufacturing parts with complex shapes and high hardness materials. Yonglihao Machinery has many years of experience and professional knowledge in WEDM, and there are some machining techniques when using WEDM, as shown below:
Selection of suitable electrode wire
The right electrode wire material (like molybdenum or tungsten) and diameter depend on the precision needs and processing conditions in the materials. Thinner electrode wire can improve accuracy. But, it is easy to break and is used for fine processing. Thicker electrode wire is more stable but slightly less accurate. It is suitable for large parts and fast cutting.
Optimize processing parameters and path
On the one hand, optimization includes pulse width, pulse interval, discharge current, cutting speed and other processing parameters. Through experiment and experience, find the best parameters for processing materials and part shapes. This will improve efficiency and surface quality. On the other hand, the cutting starting point and path are reasonably arranged to avoid frequent steering and repetitive cutting to reduce the processing time and the loss of electrode wire.
Use efficient coolant
Use high-efficiency coolant (e.g. deionized water) for cooling and rinsing to reduce thermal influence and prevent the accumulation of discharge products on the surface of the electrode wire and workpiece.
Regular maintenance of equipment
Regularly calibrate the wire-cutting equipment to ensure processing accuracy and stability. And make timely replacement for worn or aged parts.
Conclusion
This paper first introduces the definition and principle of wire EDM. Then, it introduces the types of machine tools. Next, it covers the materials suitable for WEDM. It also looks at the pros and cons of the process. Finally, it discusses common uses. It shares machining techniques to help you understand WEDM. If you still have some other questions about other aspects of wire EDM, you can contact us and we will continue to answer them for you. If you have related wire EDM needs and projects, please contact us. We will give you preliminary quotes and professional help. We look forward to hearing from you.
FAQ
Generally WEDM is only suitable for conductive materials. Non-metallic materials such as plastics and ceramics cannot be processed by this process. However, in some cases, non-metallic materials with special treatment or added conductive parts can be processed by WEDM. But, this is rare.
WEDM can achieve very high accuracy. It can hold tolerances as small as 0.0001 inches. This makes it ideal for precise applications.
WEDM is usually cheaper for small to medium volume production. It is also good for applications needing high accuracy. For mass production, other methods may be more economical.