The choice of cutting method depends on the specific situation. In addition to laser cutting, there are other methods such as water cutting, plasma cutting and wire cutting. When are they used?
According to a cutting engineer:
- Currently, the main fiber lasers and carbon dioxide lasers are being gradually phased out due to their high power consumption, but there is still a market for them in the non-metallic field.
- The price of fiber optic equipment has dropped significantly in the medium and low power range, especially since it began to be manufactured in China.
- In addition to laser cutting methods, there is a relatively large demand for plasma and wire cutting. Wire cutting is mainly used in die industries, while plasma cutting is used more often for thick sheets or low precision requirements. Water cutting is no longer common in the metallurgical industry, but is widely used in the non-metallic sector.
- In future developments, laser cutting is expected to dominate the sheet metal cutting market. Laser cutting is also expected to occupy a significant share of the non-metallic cutting market.
We will look at these various cutting techniques in more detail.
Definition of Laser Cutting, Waterjet Cutting, Plasma Cutting and Wire Cutting
Laser cut
Laser cutting is a process in which a focused laser beam of high power density is directed at the workpiece, causing the material to melt, vaporize, extinguish, or ignite. The molten material is then removed by a high-velocity air stream that is coaxial with the light beam, resulting in cutting of the part.
Currently, pulsed CO 2 lasers and fiber lasers are the most commonly used laser types for cutting. Laser cutting is considered one of the thermal cutting methods.
Water jet cutting
Waterjet cutting, also known as water knife, is a cutting machine that uses high-pressure water flow to cut materials. Under computer control, it has the ability to sculpt the part as desired with minimal impact on the quality of the material.
Water cutting is divided into two methods: sandless cutting and sand cutting.
See too:
- Waterjet Cost Calculator: #1 Free Online Tool
Plasma Cutting
Plasma arc cutting is a process that uses heat generated by a high-temperature plasma arc to melt and vaporize metal at the cutting edge of the workpiece. The momentum of the high-speed plasma is then used to eliminate the molten metal and form a cut.
Wire cutting
Wire Electrical Discharge Machining (WEDM), also known as Wire Cut Electrical Discharge Machining, is a type of electrical processing. It can be divided into fast wire cutting, medium wire cutting and slow wire cutting. WEDM fast wire cutting has a wire traveling speed of 6 to 12 m/s, and the wire moves back and forth at high speed with relatively low cutting accuracy.
Medium WEDM wire cutting is a newer technique that offers multi-frequency cutting functions based on fast WEDM wire cutting. WEDM slow wire cutting has a wire travel speed of 0.2 m/s. The electrode wire moves at low speed and unidirectionally, resulting in very high cutting accuracy.
In the following sections we will make a detailed comparison of these cutting methods.
Various comparisons of laser cutting, waterjet cutting, plasma cutting and wire cutting
App Comparison
Laser cutting machines have a wide range of applications and can cut both metallic and non-metallic materials. For example, non-metallic materials such as fabric and leather can be cut with a CO2 laser cutter. When it comes to metal cutting, a fiber laser cutting machine is preferred because of its ability to produce minimal plate deformation.
Water cutting is considered a cold cutting method and does not result in hot deformation. Produces a high quality cutting surface and eliminates the need for secondary machining. Furthermore, it is easy to reprocess if necessary. Water cutting can cut any material efficiently, with fast cutting speed and flexible processing size.
Plasma cutting machines are capable of cutting stainless steel, aluminum, copper, cast iron, carbon steel and other metal materials. However, plasma cutting has a noticeable thermal effect and low precision, making it difficult to reprocess the cut surface.
Wire cutting can only be used to cut conductive materials and requires cutting coolant during the process. As a result, non-conductive materials such as paper and leather, or materials sensitive to water or coolant pollution, cannot be cut using this method.
Cutting Thickness Comparison
The use of laser cutting for carbon steel in industry is typically limited to thicknesses of less than 20mm, with cutting capacity generally less than 40mm.
For cutting stainless steel, the typical limit is less than 16mm, and the cutting capacity is generally less than 25mm. As the part thickness increases, the cutting speed decreases significantly.
Waterjet cutting has the ability to cut materials with thicknesses ranging from 0.8mm to 100mm and in some cases even thicker materials.
The cutting thickness range for plasma cutters is 0mm to 120mm. Plasma cutters that can cut metal with a thickness of 20 mm are considered the best performers in terms of cost.
Wire cutting typically has a thickness range of 40mm to 60mm, with the ability to reach up to 600mm for the thickest cuts.
Cutting speed comparison
If a 2mm thick mild steel plate is cut with a laser power of 1200W, the cutting speed can reach 600cm/min. For a 5mm thick polypropylene resin board, the cutting speed can reach 1200cm/min. This highlights the speed advantage of laser cutting for mass production.
EDM wire cutting efficiency is generally 20mm2 up to 60mm2 per minute, with a maximum of 300mm2 per minute. In comparison, laser cutting is faster and more suitable for mass production.
The water cutting speed is relatively slow, making it less suitable for mass production.
Plasma cutting has a slow cutting speed and relatively low precision, making it more suitable for cutting thick sheets. However, the end face will have a slope.
For metal processing, wire cutting offers greater precision but has a slow cutting speed. In some cases, other methods such as drilling and thread cutting may be necessary but have limited cutting capabilities.
Cutting Accuracy Comparison
The laser cutting incision is narrow, with sides parallel and perpendicular to the surface. The size accuracy of the cut part can reach ±0.2mm.
Plasma cutting has an accuracy of less than 1 mm.
Water cutting does not produce thermal deformation and has an accuracy of ± 0.1 mm. If a dynamic water cutting machine is used, the cutting accuracy can be improved up to 0.02mm and the cutting skew will be eliminated.
Wire cutting generally has an accuracy of ±0.01mm to ±0.02mm, with a maximum accuracy of ±0.004mm.
Cutting slot width comparison
Laser cutting is more precise than plasma cutting, with small gaps of approximately 0.5 mm.
The cutting slots of plasma cutting are larger than those of laser cutting, typically 1 to 2 mm.
Water cutting results in gaps about 10% larger than the diameter of the cutting tube, typically 0.8 mm to 1.2 mm. As the diameter of the sand cutter tube increases, the size of the incision also increases.
Wire cutting has the smallest slot width, typically around 0.1mm to 0.2mm.
Cutting surface quality comparison
The precision surface roughness of laser cutting is not as good as that of water cutting, and this becomes more pronounced as the material thickness increases.
Water cutting does not change the texture of the material around the cut joint. This is because laser cutting is a thermal cutting method that changes the texture around the cut area.
Comparison of production input costs
(1) Laser cutters vary in price depending on their intended use. A cheaper option, like a CO2 laser cutter, can cost around $4,000, while a more expensive option, like a 1,000W fiber laser cutter, can cost more than $50,000. Laser cutting has no consumables, but it has the highest equipment investment and maintenance costs of all cutting methods.
(2) Plasma cutters are much cheaper than laser cutters and prices vary based on factors such as the wattage and brand of the plasma cutting machine. Plasma cutting has a high cost of use, as it can cut any material that conducts electricity.
(3) Waterjet cutting equipment is second only to laser cutting in cost, with high energy consumption and maintenance costs. It has a slower cutting speed compared to plasma cutting. Furthermore, all abrasives used are disposable and can contribute to environmental pollution.
(4) Wire cutting typically costs several thousand dollars. However, it has consumables such as molybdenum wire, cutting coolant, etc. There are two commonly used wires: one is molybdenum wire, which is expensive but can be reused many times and is used for fast wire moving equipment; the other is copper wire, which is used for slow-moving equipment, but can only be used once. Furthermore, fast WEDM machines are 5 to 6 times cheaper than slow WEDM machines.
