Basic Understanding and Industrial Application of Wire EDM Cutting Process

There are many ways to cut metal, mechanical cutting, wire cutting, laser cutting, etc. are widely used, but not all cutting methods are universal, among which wire cutting is suitable for cutting conductive materials with high accuracy, high hardness and high brittleness.

This article can help you learn more about the wire EDM process.

What is Wire EDM Cutting?

Wire EDM cutting belongs to a specific form of EDM cutting, its full name in English is Wire Electrical Discharge Machining, which is a cutting method that is hotly processed and does not touch the surface of the workpiece. It also has many common names, such as: “wire cutting”, “wire edm”, “wedm” and so on.

How does Wire EDM Work?

Wire EDM works by using electrode wire as the pulse power cathode and the workpiece to be cut as the anode.

Both the anode and cathode are immersed in a dielectric solution made of deionized water, leaving small discharge gaps. At this time, when a pulse voltage is applied, high-frequency electrical sparks will be generated in the discharge void, and the temperature will instantly rise to thousands of degrees Celsius, which will cause the local metal of the workpiece to melt or vaporize, and the dielectric solution will cool down at this time. At this time, the cutting can be completed by moving the electrode wire.

Wire EDM Cutting Type

High-speed Wire Cutting (HS-WEDM)

This method uses molybdenum wire as the power cathode and completes cutting through high-speed reciprocating motion of molybdenum wire. This cutting method has the characteristics of fast speed and low cost, and the processing accuracy will also be low.

Low-speed Wire Cutting (LS-WEDM)

Brass wire or coated wire is usually used as electrode wire, and only one-way movement is performed to complete the cutting, so the cutting speed is slow. However, the cut product has very high precision and very good surface integrity.

Wire EDM Cutting Advantages and Disadvantages

Advantages of Wire EDM Cutting

• The cut does not deform. Because wire EDM does not touch the surface of the workpiece and does not generate mechanical stress, the cutting will not deform the workpiece, and it is suitable for cutting slender, thin and light workpieces that are prone to deformation.
• Extremely high cutting accuracy: Micron-level accuracy is possible.
• High quality of the cutting surface: The finish of the cut surface is very good.
• It can be cut for conductive materials with high hardness, high strength, and strong brittleness. Including titanium alloy, carbide, hardened steel and other materials.

Disadvantages of Wire EDM Cutting

• It is not possible to cut all materials
• It can only be used to cut conductive metal materials, and other plastic, ceramic and glass products cannot be wire cut.
• Slow cutting speed. Slower speed compared to other cutting methods. For example, laser cutting, waterjet cutting, traditional mechanical cutting.
• High processing costs. Because the electrode wire as the cathode cannot be reused, the consumption is relatively large.

Difference Between Edm and Wire Cut Edm

Type	Electrical Discharge Machining	Wire Electrical Discharge Machining Cutting
Cutting electrode type	Custom-formed copper or graphite electrodes	Metal wire
Processing method	The electrode feed is used to etch the workpiece to form a forming cavity or surface	Cut the cross-section or contour of the workpiece with metal electrode wire
Electrode loss	High losses and need to be compensated	Low losses
Cutting accuracy	The cutting accuracy is high, approximately ±0.001mm	Extremely high cutting accuracy. low-speed wire EDM tolerances ±0.001-0.005mm, High-speed wire EDM tolerances ± 0.01-0.02mm.
Processing costs	High	low
Machining speed	Slower	Fast
Main types of machined workpieces	Some closed or heterogeneous surfaces such as mold cavities or cores	Open or closed contours such as special-shaped parts, punches or concave dies of molds.

Wire EDM Cutting of Titanium 

Titanium is widely used due to their high hardness and light weight. Wire EDM is very suitable for titanium products, and the following are titanium products that are often used.

Pure titanium plate, titanium alloy plate. Whether it is cold-rolled titanium plate (thickness 0.5-100mm) or hot-rolled thick titanium plate (thickness 100-300mm), it can be processed to the desired size by wire EDM.

Titanium rods, seamless titanium tubes, titanium square tubes, thin titanium strips, titanium composite plates, titanium elbow, titanium flange, titanium fasteners, etc. can all be processed by wire cutting. If it is precision machining, it usually uses the slow filament method; If it is rough processing, the fast wire method can be used, which has high processing efficiency.

Note: All titanium grades of titanium can be wire cut, but if it is titanium alloy, it must be remembered to optimize the power parameters when processing to prevent oxidation at high temperatures.

Wire EDM Cutting Applications

7.1. Automotive industry

Many parts of automobiles have special shapes and sizes, and wire EDM can meet their processing. For example, the pinion, bumper, door, fuel nozzle and other components of the car require wire EDM.

7.2. Mold manufacturing industry

Many industrial molds also need to use wire EDM in the manufacturing and processing. For example, punch dies, concave dies, inserts of extrusion molds, injection molds, extrusion molds, powder metallurgy molds, as well as semiconductor molds, precision electrode parts, etc.

7.3 Manufacture precision parts

Wire EDM is commonly used in the manufacture of many precision parts, such as precision gears, forming tools, carbide material parts, etc. Parts manufactured by the wire EDM process can also be called wire EDM parts.

7.4 High-end consumer goods customization

Some jewelry and watch customizations also use wire EDM to process more complex design patterns.

7.5 Medical field

In the medical field, many sophisticated instrument manufacturing processes require wire EDM, including some surgical instruments and surgical implants, which have relatively high requirements for size and tolerance, and wire EDM cutting can be achieved.

7.6 Aviation and defense sector

The manufacture of relevant instruments and components in the aerospace and defense sectors requires extremely high dimensions and tolerances, and the wire EDM process is of course essential. For example, engine blades, aircraft precision structural parts, etc.

Conclusion

The advantages of not touching the workpiece surface, high precision, and high cutting quality make wire EDM an irreplaceable position in the manufacturing field. Wire EDM is also very important in the processing of titanium products, if you have titanium products or titanium product processing needs, we can also provide wire EDM cutting services and titanium products.

FAQ

1. Can any thickness of material be wire EDM cutting?
No, wire EDM can usually only cut materials up to 40mm thick.

2. What tolerance can be achieved for wire EDM cutting?
Generally, wire EDM tolerances can reach 0.00254mm, which is 0.0001 inches, which is very precise. In addition, some special machines can even achieve tolerances of 0.000004 inches (0.0001016 mm).

3. What titanium products can be processed by wire EDM cutting?
Wire EDM can process all grades of pure titanium or titanium alloy products. For example: titanium plates, titanium rods, titanium tubes, titanium elbows, titanium flanges, titanium fasteners, titanium sintered porous plates, titanium sintered porous filter cartridge, and other titanium castings and titanium forgings can all be processed by wire EDM.

4. What is the wire EDM cutting speed?
The speed of high-speed wire cutting (HS-WEDM) is about 8-10 m/s, and the speed of low-speed wire cutting (LS-WEDM) is about 0.2 m/s. The cutting accuracy and surface quality are the highest in slow wire cutting.

5. What are the types of wire cutting machines?
The types of wire cutting machines can be divided into three categories according to the method of wire cutting: fast wire cutting machine, medium wire cutting machine, and slow wire cutting machine. Others include laser wire cutting machines, CNC wire cutting machines, and so on.