The cutting process is one of the important processes for manufacturing parts and is a typical subtractive manufacturing technology.Cutting technology has evolved from the initial manual and mechanical cutting to the current high-energy beam instead of cutting method – laser cutting.Laser cutting is a process that uses energy beams to cut different materials for industrial manufacturing or other artistic applications such as etching.It’s a thermal cutting process in which an energy beam is focused on the surface of a material to melt or evaporate or vaporize the material to achieve the final desired shape of the part. This technology makes it easier and more precise to manufacture components with intricate details.At present, this technique is one of the most effective and labor-free techniques for cutting metal plates.
This article is a basic guide to laser cutting of sheet metal, mainly providing basic information about laser cutting and some necessary information. Now keep reading
- What is Sheet Metal Laser Cutting?
- How does sheet metal laser cutting work?
- Multiple advantages of laser cutting sheet metal
- The type of laser for sheet metal laser cutting
- The type of process for laser cutting sheet metal
- The laser cutting service for sheet metal parts you need
What is Sheet Metal Laser Cutting?
At present, the most popular manufacturing process in the field of metal parts manufacturing is subtractive processing.Laser cutting is a type of subtractive processing. It is one of the standard methods of cutting and removing parts from plates.It runs on top of computer numerical control (CNC) technology, requiring technicians to enter detailed design drawing codes into a computer for control, which uses highly focused, coherent beams of light to cut metal, paper, wood, and acrylic. In the cutting process, the parts are mainly removed by vaporization, melting, ablation, etc. to obtain the final product.Since this process is controlled by optical and computer numerical control technology, the precision of laser cutting parts is very high. Its laser optics can easily drill holes as small as 5 microns without creating residual stresses on the material during the process, so it can also be applied to cutting fragile materials.
How does sheet metal laser cutting work?
Laser cutting uses optical and computer numerical control technology to guide the energy beam to focus on the plate to be cut, and the focused laser energy beam processes the plate to form the required shape by combustion, melting, evaporation or vaporization. A laser is a high-intensity light source generated within the cavity of a reflective laser and emitted by a laser. The reflected laser cavity contains a laser rod that produces radiation, and the laser rod atoms produce a stimulated reflection when absorbing the wavelength of light passing through the light source, causing a series of photons to excite other charged atoms to produce a stimulated reflection to produce more photons.
This light is focused in the working area through a mirror or optical fiber, which guides the beam through the lens to enhance the beam. At its narrowest point, the diameter of the laser beam is typically less than 0.0125 inches (0.32 mm). Depending on the material thickness, the incision width may be as small as 0.004 inches (0.10 mm). If the laser cutting process needs to start anywhere other than the edge of the material, the perforation technique is used, that is, a high-power pulsed laser is used to punch holes in the material. For example, it takes 5-15 seconds to burn through a 0.5-inch-thick (13mm) stainless steel plate. When the spot hits the material, it is quickly heated to vaporization temperature and evaporates to form holes. As the beam moves on the material, the auxiliary gas (carbon dioxide gas, oxygen, nitrogen, etc.) blows away the molten waste residue, forming a narrow width (such as about 0.1mm) slit, which completes the cutting of the material.
Multiple advantages of laser cutting sheet metal
High-precision cutting for increased productivity
Like shearing and stamping, lasers are precise, flexible and efficient. But the laser cutting process was born to replace shearing and stamping. In cutting manufacturing, laser cutting is the melting and evaporation of materials with high-energy lasers, so its accuracy is unmatched by other cutting processes. The relevant data shows that the tolerance level of other cutting processes is about 1-3mm, and the accuracy of laser cutting machines can be as low as 0.003mm. The laser cutting machine only needs to design the cutting pattern, import it into the control system and set the size to cut. At the same time, due to the high temperature of the laser melting the material to be cut, the cut product has little or no burrs, leaving a clean, smooth, sharp edge. It directly shortens the cycle of product production, processing and manufacturing, and effectively improves labor productivity.
The workpiece is not damaged, and the cutting quality is good
Since the laser cutting machine uses a computer control system for accurate measurement and control, there is no direct contact with the workpiece during cutting, so it will not damage the workpiece. The cut product does not extrude deformation, does not produce burrs and does not warp.The laser-cut workpiece has a fine, smooth surface. The cut workpiece will only leave a very fine cutting surface, no manual re-grinding, eliminating the post-processing process and saving labor costs.
The materials are compatible and highly applicable
The laser’s high energy density is enough to melt any metal, and it can cut and drill different materials which are difficult to achieve with traditional processing techniques. It is especially suitable for some difficult to machine high hardness, high brittleness, high melting point materials, such as titanium and super alloy steel. In addition to processing metallic materials, it can also be used to cut non-metallic materials such as crystals, ceramics, and even diamonds.
Save mold cost and low cost
Now laser cutting technology is quite mature, and the purchase price of laser cutting equipment is cheap. Laser cutting technology is not like the traditional processing technology needs to develop molds, it can directly process a variety of hardware workpieces, so there is no mold consumption, nor does it need to repair and replace molds, which can save a lot of mold costs and reduce production costs. This feature makes it particularly suitable for the processing of bulky products. In addition, laser cutting is not limited to cutting patterns. The computer program can automatically typeset to save materials, further reducing material loss and saving costs.
The type of laser for sheet metal laser cutting
Different from other cutting processes, the principle of laser cutting is “light amplification by stimulated radiation”. The laser is generated by a high-intensity light source that reflects the laser cavity, so it requires higher power density and shorter interaction times.
Lasers used to cut materials in industrial manufacturing can be divided into three different forms, CO2 lasers, neodymium (Nd) in the same style, and neodymium yttrium aluminum garnet (Nd:YAG). CO2 is widely used for cutting, drilling and engraving, Nd is mainly used for high-energy, low-repetitive drilling, and Nd:YAG is commonly used for high-power drilling and engraving. Because each laser cutter has different unique features, a comprehensive summary of the three different lasers is described below.
Fiber lasers are the newest and most popular type of laser in the metal cutting industry. Since lasers can be amplified in glass fibers, fiber lasers use fiber optic cables made of quartz glass to direct light. It belongs to the solid-state laser, which can generate huge power to achieve extremely precise cutting.
Although fiber lasers have wider cutouts than other types of lasers, the energy density of the beam is high and stable. It produces a much smaller spot size than those achieved using CO2 technology, a property that makes it ideal for cutting reflective metals. At the same time, it has a service life of more than 25,000 hours and usually requires less maintenance, making it the most durable laser.
Fiber lasers often incorporate different mixtures to adjust the different wavelengths of the laser (e.g., erbium produces erbium, which produces light in the range of 1528 nm to 1620 nm). Ytterbium produces light at wavelengths of 1030 nm, 1064 nm, and 1080 nm), including ytterbium, thulium, and erbium, for different cutting scenarios.
At present, the basic settings of fiber lasers on the market are single-mode and multi-mode. Single-mode lasers have core diameters between 8 μ and 9 μ, while multimode lasers have core diameters of 50 μ to 100 μ. In both modes, single-mode lasers are more efficient and produce better beam quality.
Fiber lasers are suitable for cutting almost all materials, from metals to alloys and non-metals (including wood, glass and plastics). In addition to cutting, they are suitable for other operations such as annealing and engraving.
Carbon dioxide (CO2) lasers
Carbon dioxide (CO2) lasers involve an electric current excited through a gas mixture (DC excitation), or now more popular is a new technique that uses radio frequency energy (RF excitation). The medium of a gas discharge laser is filled with 10 – 20% carbon dioxide, 10 – 20% nitrogen, trace amounts of hydrogen and xenon, and balanced helium. Common variants of CO2 lasers include fast axial flow, slow axial flow, lateral flow, and flat plate. However, the RF method has external electrodes to avoid corrosion with the electrodes and plating of the electrode material on glassware and optics, which can occur with DC using electrodes in the cavity.
Instead of light, the laser pumps the light by releasing an electric current. When the discharge passes through the laser medium, the nitrogen molecule is excited, which transfers its vibrational mode energy to the CO2 molecule. This process continues until most CO2 molecules are in a metastable state. The CO2 molecule then emits 10.6 μm or 9.6 μm of infrared light, reducing the energy level, and the CO2 molecule returns to the ground state through the transfer of surplus energy to the helium atom. The cold helium atoms heat up and are also cooled by the laser’s cooling system. CO2 lasers are about 30% efficient and can reach higher energy levels than other lasers.
The gas and cutting principles of carbon dioxide (CO2) lasers lay the foundation for their efficient and cost-effective cutting, and can also cut a wide range of materials at high speeds, and laser cutting service providers generally use them to cut non-metallic and organic materials such as wood, paper, acrylic, etc. However, compared to light lasers, they produce less cutting power, so they cannot be used to cut metal and alloy materials with high hardness and thickness.
Crystal lasers (Ruby, Nd, and Nd-YAG)
Crystal lasers differ from CO2 lasers in that they are solid-state lasers which use synthetic crystals as the laser medium. It mainly comes in two forms: Nd:YAG (neodymium-doped yttrium aluminum garnet) and Nd:YVO (neodymium-doped yttrium vanadate, YVO4) crystals. Currently the most popular are YAG (Y3Al5O12) crystals doped with 1% ionized neodymium (Nd3+).
The principle of this crystal laser is that the laser pump excites the Nd ion to a higher energy level through a krypton flash or laser diode. Excitation of Nd ions enter a lower, more stable state without emitting photons. This process continues until the medium is filled with excited Nd ions. The Nd ion emits infrared light with a wavelength of 1064 nm from its metastable state.
These lasers are cutting devices with incredibly high-power, but they are very expensive and undurable, with short half-lives. The life expectancy is also half that of fiber lasers, which is about 8,000 to 15,000 hours. They are suitable for cutting coated and uncoated metals, non-metals, plastics and ceramics, etc. in specific situations.
The type of process for laser cutting sheet metal
Sublimation or vaporized cutting
Sublimation cutting uses laser evaporation or melting of materials. The laser beam has a high power density and can be converted into thermal energy, and the material is rapidly heated to the evaporation temperature so that part of the material evaporates. This cutting method uses inert gas (nitrogen, helium, argon) as the cutting gas as the cutting gas as the melting method, but make sure that the cutting edge is free of oxidants. Although the cutting efficiency is slower than other methods, it can be used to cut high-quality edges with high precision. This process is suitable for cutting plastics, textiles, wood, paper and foam and requires only a small amount of energy to evaporate.
Laser melt cutting
Compared to sublimation cutting, melting cutting requires less energy to achieve, which requires only 10% of the energy required for sublimation laser cutting. Melt cutting uses an inert cutting gas (usually nitrogen, helium, argon) to push the molten material out of the torch. Due to the use of inert gases, low-reaction gases constantly vaporize the cutting gap of the material, which prevents oxidation at the cutting edge. At the same time, during the melting and cutting process, the laser beam heats the material to melt it, and when the material melts, the gas jet of the coaxial nozzle discharges the material from the incision together with the laser beam and does not react with the material.
This laser cutting method is suitable for cutting flat, non-oxidizing or reactive metals such as titanium, thin aluminum alloys and stainless steel plates, as well as where the material must meet high visual requirements and less post-processing requirements.
Laser beam flame cutting (oxidation cutting, flame cutting)
Laser beam flame cutting mainly uses oxygen, a combustible gas, to spray molten materials. When the material is melted, oxygen is ejected from the coaxial nozzle to create an exothermic reaction with the molten metal (the reaction releases a large amount of energy up to five times the energy of the laser), and this heat can help melt the material. Oxyfuel cutting is the standard process for cutting fusible materials such as mild steel and ceramics. Since the applied gas is oxygen, an oxidizing agent, this cutting process may cause burns on the cutting surface, and proper optimization of process parameters will help prevent burr formation. This process is commonly used to cut thick carbon steel, titanium steel and other oxidizable metals.
The laser cutting service for sheet metal parts you need
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We are a trusted company that provides sheet metal fabrication services for rapid prototyping and custom production. We can guarantee that the sheet metal laser cutting services provided are of high quality, and can also provide cost-effective on-demand customized solutions according to your requirements.
We can provide small batch prototypes and high volume production services. Working with Elimold, you can be sure that your products are free of sheet metal fabrication issues, and even when dealing with custom products with intricate details, you can get the same quality of service as well as the final product. In addition, we also provide services such as CNC machining, 3D printing, injection molding and die casting.
Laser cutting is a rapid manufacturing technique for cutting materials. After reading the content of this article, you should have a comprehensive understanding of sheet metal laser cutting technology, including what laser cutting is, its advantages, process types and common laser types. It is the manufacturing process of choice for manufacturing high-volume parts with high dimensional accuracy requirements. You can decide whether to apply the method to your manufacturing needs.
If you want to work with a company that can provide quality laser cutting services, Elimold’s sheet metal laser cutting services are the ideal service for your manufacturing needs. We are an ISO-certified company that provides best-in-class sheet metal fabrication services for rapid manufacturing and custom production. Whether it’s sheet metal bending, stamping, welding, etc., we can meet all your processing needs.