With the development of technology, there are more and more cutting methods, such as: laser cutting, water cutting, plasma cutting, wire cutting…What is the difference between them?
Hear an engineer engaged in cutting field say:
(1) Now the mainstream fiber lasers in the market, carbon dioxide lasers are slowly being eliminated, and the energy consumption is too high. There is still a market in the non-metallic field.
(2) Now that the fiber optic equipment has been manufactured in China, the price has dropped sharply in the low and medium power sections.
(3) Other cutting methods besides laser, the market demand for plasma and wire cutting is relatively large, but the mold industry targeted by wire cutting is more, plasma is more demanded when thick plates or precision requirements are not high, water jet cutting Now it is not common in the metal industry, there are many in the non-metallic field.
(4) In the future development, laser cutting in metal thin plates is definitely the world, including non-metallic cutting will also occupy a considerable part of the market by laser cutting.
Next we analyze these several cutting techniques.
Laser cutting
Optical cutting is to use a focused high-power density laser beam to irradiate the workpiece, so that the irradiated material quickly melts, vaporizes, ablate or reaches the ignition point, and at the same time, the molten material is blown off by the high-speed air flow coaxial with the beam, thereby cutting the workpiece open. Currently, CO2 pulse lasers are generally used, and laser cutting is one of the thermal cutting methods.
Water cutting
Water cutting, also known as waterjet, which is a high-pressure water jet cutting technology, is a machine that uses high-pressure water jet cutting. Under the control of the computer, the workpiece can be sculpted arbitrarily, and it is little affected by the texture of the material. Water cutting is divided into two methods: no sand cutting and sand cutting.
Plasma cutting
Plasma arc cutting is a processing method that uses the heat of a high-temperature plasma arc to locally melt (and evaporate) the metal at the cut of the workpiece, and uses the momentum of high-speed plasma to remove the molten metal to form the cut.
Wire cutting
Wire Electrical Discharge Machining (WEDM) belongs to the category of electrical machining. Wire cut Electrical Discharge Machining (WEDM) is sometimes called wire cutting. Wire cutting can be divided into fast wire cutting, medium wire cutting, and slow wire cutting. The wire-traveling speed of fast-wire EDM wire cutting is 6～12 m/s, and the electrode wire performs high-speed reciprocating motion, and the cutting accuracy is poor. Medium wire EDM wire cutting is a new process developed in recent years that realizes the function of frequency conversion multiple cutting on the basis of fast wire cutting. The wire-traveling speed of slow-wire EDM wire cutting is 0.2m/s, and the electrode wire performs low-speed unidirectional movement, and the cutting accuracy is very high.
1. Comparison of application scope
The application range of laser cutting machine is very wide, whether metal or non-metal, it can be cut, cutting non-metal, such as cloth, leather, etc. can use CO2 laser cutting machine, cutting metal can use fiber laser cutting machine. The deformation of the plate is small.
Water cutting is cold cutting, no thermal deformation, good cutting surface quality, no secondary processing, if necessary, it is easy to perform secondary processing. Water cutting can punch and cut any material, with fast cutting speed and flexible processing size.
Plasma cutting machine can be used to cut various metal materials such as stainless steel, aluminum, copper, cast iron, carbon steel, etc. Plasma cutting has obvious thermal effect, low precision, and it is not easy to cut the surface for secondary processing.
Wire cutting can only cut conductive materials, and cutting coolant is required during the cutting process, so it is impossible to cut materials that are not conductive, such as paper and leather, and are afraid of water and contamination of cutting coolant.
2. Comparison of cutting thickness
The application of laser cutting carbon steel in industry is generally below 20mm. Cutting capacity is generally below 40mm. The industrial application of stainless steel is generally below 16mm, and the cutting capacity is generally below 25mm. And as the thickness of the workpiece increases, the cutting speed decreases significantly.
The thickness of water cutting can be very thick, 0.8-100mm, or even thicker materials.
The plasma cutting thickness is 0-120mm, and the plasma system with the best cutting quality range thickness of about 20mm has the highest cost performance.
The thickness of wire cutting is generally 40 ~ 60mm, and the maximum thickness can reach 600mm.
3. Comparison of cutting speed
Using a laser with a power of 1200W to cut a 2mm thick low carbon steel plate, the cutting speed can reach 600cm/min; cutting a 5mm thick polypropylene resin board, the cutting speed can reach 1200cm/min. The cutting efficiency that can be achieved by wire EDM is generally from 20 to 60 square millimeters/minute, up to 300 square millimeters/minute; obviously, the laser cutting speed is fast and can be used for mass production.
Water cutting speed is quite slow, not suitable for mass production.
Plasma cutting has a slow cutting speed and low relative accuracy. It is more suitable for cutting thick plates, but the end face has a slope.
For metal processing, wire cutting has higher accuracy, but the speed is very slow. Sometimes it is necessary to use other methods to pierce and thread to cut, and the cutting size is greatly limited.
4. Comparison of cutting accuracy
The laser cutting incision is narrow and narrow, the two sides of the slit are parallel and perpendicular to the surface, and the dimensional accuracy of the cut parts can reach ±0.2mm.
Plasma can reach within 1mm.
Water cutting will not cause thermal deformation, and the accuracy is ±0.1mm. If a dynamic water cutting machine is used, the cutting accuracy can be improved, and the cutting accuracy can reach ±0.02mm, eliminating the cutting slope.
The precision of wire cutting is generally ±0.01～±0.02mm, and the highest can reach ±0.004mm.
5. Comparison of slit width
Laser cutting is more precise than plasma cutting, and the slit is small, about 0.5mm.
Plasma cutting slit is larger than laser cutting, about 1-2mm.
The slit of water cutting is about 10% larger than the diameter of the knife tube, generally 0.8-1.2mm. As the diameter of the sand knife tube is flared, the cutout becomes larger.
The slit width of wire cutting is the smallest, generally about 0.1-0.2mm.
6. Comparison of cutting surface quality
The surface roughness of laser cutting is not as good as water cutting, and the thicker the material, the more obvious.
Water cutting does not change the texture of the material around the cutting seam (laser belongs to thermal cutting, it will change the texture of the surrounding area of the cutting area).
7. Comparison of production input cost
1) Different types of laser cutting machines have different prices. Cheap carbon dioxide laser cutting machines only cost 20,000 to 30,000. Expensive fiber laser cutting machines such as 1000W cost more than one million. Laser cutting has no consumables, but the investment cost of equipment is the highest among all cutting methods, and it is not a little high, and the maintenance cost is also quite high.
2) Plasma cutting machines are much cheaper than laser cutting machines. Depending on the power and brand of the plasma cutting machine, the price varies, and the cost of use is high. Basically, as long as it can conduct conductive materials, it can cut.
3) The cost of water cutting equipment is second only to laser cutting, with high energy consumption and high maintenance costs. The cutting speed is not as fast as plasma, because all abrasives are disposable, and they are discharged into nature once used. Therefore, the environmental pollution caused by it is relatively serious.
4) Wire cutting is generally around tens of thousands of pieces. However, there are consumables for wire cutting, such as molybdenum wire and cutting coolant. There are two kinds of wire commonly used in wire cutting. One is molybdenum wire (molybdenum is expensive), which is used for fast-moving wire equipment. The advantage is that the molybdenum wire can be reused many times; the other is copper wire (which is much cheaper than molybdenum wire anyway). ), used for slow wire equipment, the disadvantage is that copper wire can only be used once. In addition, the fast-moving machine is far cheaper than the slow-moving machine, the price of one slow-moving wire is equal to 5, 6 fast-moving wire.