There are several uses for laser cutting, a thermal technique, in industrial production. Even the most intricately shaped metal sheets may be swiftly engraved and sliced by laser cutting devices, providing superior results.
A laser cutter is a device that creates 2-dimensional components for both industrial and hobbyist usage by cutting into a variety of plate or sheet materials using a high-energy focused laser beam. Steel, wood, and some polymers are common materials.
In addition to outlining the distinctions between the different laser cutting methods. Well in this reading, we’ll explore what a laser cutting is, it uses, types, materials, and how it works. we’ll also talk about it advantages and disadvantages.
What is laser cutting?
Laser cutting is the method of cutting materials using a high-power laser that is guided by computer numerical control (CNC) via optics.
This method is commonly used to cut materials, including metals, plastics, ceramics, wood, textiles, and paper, in a variety of sectors, including automotive, aerospace, electronics, and medical.
With the aid of a coaxial gas jet, a concentrated laser beam is utilized in laser cutting to melt material in a specific location and produce a kerf. Gas has no influence on the laser beam itself, but it may efficiently burn, melt, or evaporate objects.
Any debris that results can then be blown away, guaranteeing a high-quality final edge. Etching and welding could also be done using laser cutting.
Neodymium (Nd) lasers, CO₂ lasers, and neodymium yttrium-aluminum-garnet (Nd:YAG) lasers are the three primary methods for laser cutting. The performance of a laser may be influenced by its kind.
Accuracy, precision, less contamination, and simpler workholding are some benefits of laser cutting. Specifically, fiber lasers are renowned for their exceptional precision cutting capabilities.
The ability of fiber lasers to provide a constant beam quality over extended distances is one of its main advantages; this allows for uniform cutting across a range of materials and thicknesses. This uniformity reduces the need for further processing and enhances edge quality.
Light Amplification by Stimulated Emission of Radiation,” or “Laser,” is an abbreviation that refers to the physics of producing laser light. Although the basic principles of laser physics are still the same, this technology is often used in three ways: Nd:YAG lasers, CO2, and fiber.
Common Uses of Laser Cutting
- Sheet metal cutting is a common technique for cutting plates and sheets of different materials.
- Engraving: Adds elegant wood markings or serial numbers to almost any material.
- Laser Welding: Using a laser beam, metals or thermoplastics may be precisely joined.
- Tube Cutting: This method cuts intricate profiles on hollow parts using a rotating axis.
Diagram
Types Of Laser Cutting
Three different kinds of lasers are often used in laser cutting applications. In contrast to solid-state fiber and Nd, CO2 lasers employ CO2 along with various inert gases as the lasing medium. A crystal serves as the lasing medium in YAG lasers. These various lasers all work on essentially the same premise.
Nd:YAG/Nd:YVO Lasers
A neodymium (Nd)-doped yttrium aluminum garnet crystal (Y₃Al₅O₁₂) is used in an Nd:YAG laser. Some yttrium ions (+-1%) are swapped out for Nd³⁺ ions due to doping.
Two mirrors, one completely reflecting and one semi-reflective, are positioned between this crystal. A set of laser diodes or a xenon/krypton flash tube serves as the pumping photon source.
The pumping source in Nd:YAG crystals provides photons that elevate the neodymium ions’ energy level. After being mirrored between the mirrors, the ions decay to emit a series of photons that combine to form a coherent laser beam.
A lens on the cutting head is used to concentrate the beam of coherent, high-intensity light, which has a frequency of 1064 nm, after it has been directed to it by mirrors.
Neodymium-doped vanadate crystals (YVO₄) are used in Nd:YVO lasers, which function similarly to Nd:YAG lasers. Nd:YVO lasers, on the other hand, can produce more pulses per second, have better power stability, and emit less heat.
Nd:YAG lasers are perfect for marking and etching because they offer a higher power density and a better beam quality than fiber lasers. Nd:YAG lasers, on the other hand, have single-digit energy efficiencies and significantly higher operational costs.
Fiber Lasers
A doped fiber optic cable serves as the lasing medium in fiber lasers. Photons are pumped into one end of a quartz or boron silicate glass core fiber optic filament to create a fiber laser beam.
These photons follow the fiber optic filament until they arrive at the rare earth element-dosed region. Neodymium, yttrium, erbium, or thulium are examples of typical elements.
When stimulated by the photons, each of these rare earth elements will generate a laser with a distinct wavelength. Fiber Bragg gratings are then used to increase the light.
Similar to the reflecting and semi-reflective mirrors used in Nd:YAG and CO2 lasers, these gratings reflect light back and forth, producing a cascade of photons.
The light can go through the grating as a high-intensity coherent beam of light once the intensity exceeds a particular threshold. Similar to other lasers, a fiber laser uses gas to help facilitate cutting or to blast molten material out of the laser beam’s path.
Fiber lasers’ typically shorter wavelengths result in increased absorption, making them ideal for reflecting materials and producing less heat during cutting.
For instance, a fiber cutting head may be readily connected to a 6-axis robot arm due to the fiber optic cable’s flexibility, eliminating the need for numerous mirrors to steer the laser, which is necessary for a CO₂ or Nd:YAG laser.
The electrical efficiency of fiber lasers is better than that of CO₂ lasers. For this reason, reflecting materials and materials that absorb heat effectively, like copper or gold, are ideal for cutting with fiber lasers.
CO₂ Lasers
The components of a CO₂ (carbon dioxide) laser are a tube filled with CO₂, helium, and nitrogen gas. Helium and nitrogen are added to boost laser efficiency. The nitrogen serves as a short-term energy reserve that may be transferred to the CO₂ molecule upon photon release.
In contrast, once the CO₂ molecule releases a photon, the helium uses kinetic energy transfer to drain out any residual energy, allowing it to absorb energy from the nitrogen molecule.
The tube has a totally reflecting mirror on one end. There is just partial reflection from the mirror at the opposite end. The tube’s gas is ionized by a powerful electric field that excites the CO₂ molecules’ electrons to a higher energy state, producing a photon and light.
The excited state of an atom releases a photon when a photon passes close to it. Then, once enough photons have been gathered to flow through the semi-reflective mirror, these photons bounce off the two mirrors.
The tube is cooled using a low-temperature gas or liquid because maintaining a low temperature inside the tube is essential for maximum efficiency. In certain systems, gas is recycled to lower operating expenses.
CO₂ lasers are good all-purpose lasers with a wavelength of 10600 nm that can cut sheet and plate metals as well as a variety of other materials. High heat absorption and highly reflective materials, however, are difficult for CO₂ lasers to work with.
Process Of laser cutting
Usually, a good lens is utilized to concentrate the laser beam on the work area. The concentrated spot size is directly related to the beam quality. Typically, the concentrated beam’s narrowest section has a width of less than 0.0125 inches (0.32 mm).
Kerf widths of as little as 0.004 inches (0.10 mm) are achievable, depending on the thickness of the material. Every cut begins with a puncture so that the blade may begin from somewhere other than the edge.
A high-power pulsed laser beam is often used for piercing, which takes 5 to 15 seconds for materials like 0.5-inch thick (13 mm) stainless steel.
The laser source’s parallel coherent light beams typically have a diameter of 0.06 to 0.08 inches (1.5 to 2.0 mm). In order to generate an extremely powerful laser beam, this beam is often concentrated and enhanced by a lens or mirror to a very small area of around 0.001 inches (0.025 mm).
The direction of the beam polarization must be adjusted as it circles the edge of a contoured workpiece to provide the cleanest finish possible during contour cutting. The focus length for sheet metal cutting is typically 1.5 to 3 inches (38 to 76 mm).
Compared to mechanical cutting, laser cutting has the advantages of simpler work holding and less workpiece contamination since there is no cutting edge that might contaminate the material.
Since the laser beam does not wear during the procedure, precision may be improved. Additionally, because laser systems only have a tiny heat-affected zone, there is less danger of distorting the material being cut.
Additionally, certain materials are impossible or extremely difficult to cut using conventional methods. Although most industrial lasers cannot cut through the thicker metal that plasma can, laser cutting for metals has the benefit of being more accurate and consuming less energy when cutting sheet metal.
Though their capital cost is significantly higher than that of plasma cutting machines that can cut through thick materials like steel plate, newer laser machines operating at higher power (6000 watts, compared to the 1500 watt ratings of early laser cutting machines) are getting close to plasma machines in their ability to cut through thick materials.
Common Laser Cutting Materials
A variety of materials may be sliced with laser cutters. The following is a list of some of the most often sliced materials:
Felt
Felt is an inexpensive, non-woven fabric that is challenging to cut by hand but readily cut using a laser cutter. Place mats, ornamental patches, and clothing may all be made from felt. Using 95–100% wool felt is advised since synthetic felt, which is frequently comprised of acrylic, cuts very badly.
Leather
Wallets, belts, and shoes are all made of leather, a durable, natural material. Leather has a high perceived value and is readily laser-cut and engraved, particularly when used to make customized laser-cut objects.
Fake leather is a term used to describe fake leather. Some of these, meanwhile, could include PVC, which when laser-cut, releases corrosive fumes.
cork
The bark of the cork oak tree yields cork, a soft hardwood substance that is frequently used for pinboards, non-slip coaster bases, and shoe insoles. It is quite easy to laser cut and engrave cork.
Hardboard
Hardboard is a tougher, more durable option than MDF (Medium Density Fiberboard), while being denser. An glue is used to join the wood fibers.
This adhesive vaporizes while cutting. This emits harmful gases that necessitate the usage of an exhaust system. Because hardboard is homogeneous, cutting and engraving are reliable.
Wood
CO2 lasers with relatively modest power (150–800 W) can easily cut wood. However, since laser cutting wood produces smoke, an exhaust system is essential.
Because of their grain structure, natural timbers can have uneven finishes when cut or engraved. It is possible to laser cut both hardwoods and softwoods.
Brass
Copper, zinc, and a few other secondary alloying metals combine to form brass. Brass has minimal friction, electrical conductivity, and resistance to corrosion. Electrical applications and low-friction bushes are common uses.
Aluminum
A variety of aluminum alloys with various alloying components and uses are collectively referred to as aluminum. Because of its favorable strength-to-weight ratio, aluminum is frequently utilized in aircraft applications.
When melted, aluminum is reflective, which makes cutting it challenging. Although aluminum may be cut using a CO2 laser, a fiber laser is the most effective tool for cutting aluminum.
Stainless steel
Chromium and/or nickel are the primary alloying elements found in stainless steel, which is categorized as a steel alloy. A large variety of substances cannot harm stainless steels. Any laser cutting method can easily cut stainless steel. But for cutting stainless steel, fiber lasers work better.
Mild steel or carbon steel
A broad variety of steels with differing concentrations of carbon as their primary alloying ingredient are referred to as “carbon steel.” Another kind of carbon steel with a carbon content of less than 0.3% is mild steel. Steel gets stronger the more carbon it has. Plates as thick as 20 to 25 mm can be sliced by high-power lasers.
PMMA, or acrylic
Although acrylic creates a clean cutting edge, the volatile fumes it emits necessitate an exhaust system. In order to firm the cut edge, the gas pressure needs to be adjusted to both blow away the vapors and cool it.
When the cut edge is still molten, too much air pressure will cause it to bend. Acrylic is sometimes referred to by its chemical name, polymethyl methacrylate, or by its marketing name, Perspex®.
How Does Laser Cutting Work?
A high-power laser is used in laser cutting, and the beam or material is guided by optics and computer numerical control (CNC). The technique usually follows a CNC or G-code of the design to be cut onto the material using a motion control system.
The concentrated laser beam produces a superior surface-finished edge by burning, melting, vaporizing, or being blasted away by a gas jet. Electrical discharges or lamps inside a closed container stimulate the lasing materials to produce the laser beam.
A partial mirror is used to reflect the lasing material within, amplifying it until its energy is sufficient to allow it to exit as a stream of coherent monochromatic light. Mirrors or fiber optics focus this light on the work area by guiding the beam via a lens that enhances it.
A laser beam’s diameter at its narrowest point is normally less than 0.0125 inches (0.32 mm), however depending on the thickness of the material, kerf widths as thin as 0.004 inches (0.10 mm) are feasible.
A piercing procedure is utilized when the laser cutting process has to begin somewhere other than the material’s edge. In this method, a high intensity pulsed laser creates a hole in the material; for instance, it takes 5 to 15 seconds to burn through a sheet of stainless steel that is 0.5 inches (13 mm) thick.
Advantages Of Laser cutting
One popular industrial method is laser cutting. Some of the main benefits that contribute to laser cutters’ widespread use in manufacturing are listed below:
- Versatile Materials: Nearly any material may be processed by laser cutters. The material being cut, the laser power, and the laser technology all have a significant impact on the maximum thickness of material that a laser cutter can cut.
- Restricted Post-processing: Laser-cut parts don’t need a lot of post-processing. Cut edges, however, might need to be deburred in some situations, such as when cutting metal, because there might be some slag adhered to the edge.
- Narrow Cuts: Depending on the material and thickness, lasers can focus on extremely narrow beams, allowing for extremely tiny cut widths (as little as 0.1 mm).
- High Precision: Unlike other technologies, such as CNC routers, laser cutters do not put any strain on their heads. Laser cutters are therefore incredibly exact and precise.
- High Speed: 2D profiles may be swiftly carved out by laser cutters. High speeds may be achieved while cutting flexible materials like plastic.
- Automated: A lot of automation goes into laser cutters. Certain machines can even unload parts and set raw materials on the cutting bed with little assistance from humans.
- Tooling Costs: A variety of tools are not used by laser cutters, in contrast to CNC machining. Since the laser cutter head does not come into touch with the raw material, there is no tool wear from friction.
- No Workholding: Clamps and other workholding tools are not necessary for laser cutters to cut. Simply lay the material on the cutting bed; it won’t move while being cut.
Disadvantages of Laser Cutting
Even with all of its benefits, laser cutting still has several drawbacks, which are detailed below:
- High electricity Consumption: Laser cutting, particularly CO2 laser cutting technology, uses a lot of electricity.
- Limited Thickness: The thickness that laser cutters can cut is constrained by the mechanics of directing a laser beam into a high-intensity point.Typically, they are restricted to materials that are plate and sheet and have a maximum thickness of 25 mm. Although thicker material may be cut, ordinary fabrication firms don’t often accomplish this.
- Hazardous Fumes: When cutting certain materials, such as plastic or wood, hazardous combustion fumes may be produced, which need to be released.
- Expensive Maintenance: The laser tube is a worn item that needs to be updated, often at a high cost, in some laser technologies (such CO2).
- High Initial Cost: Laser cutters require a large initial capital outlay. Cheaper technology, such as plasma or flame cutters, could be more appropriate in some circumstances.
FAQs
What is meant by laser cutting?
The method known as laser cutting creates a cut edge by vaporizing materials with a laser. Although it was originally used for industrial production, schools, small enterprises, architects, and hobbyists increasingly utilize it.
How much does it cost to laser cut?
The cost of production time for engraving and laser cutting is £1 per minute. A 30-minute service will cost £30, including supplies and setup fees for the artwork. The production time would be £60 if it took one hour. Depending on the intricacy and level of intensity of the work, a discount may be available for larger assignments.
What is the method of laser cutting?
In the laser cutting process, a laser beam is focused to a small point with enough power density to create a laser cut, generally using a lens (and occasionally a concave mirror). The distance between the lens and the focused spot, or focal length, defines the lens.
What is laser cutting good for?
As the heat is transmitted over the bed to cut sections from the material sheet, it melts and frequently vaporizes the material. Parts are taken out and could be processed further. Among the many uses for laser cutters include engraving, tube cutting, laser welding, and cutting sheet metal and plates.
Why is laser so expensive?
These elements include the cost of machine upkeep and repairs, the cost of technician certification and training, and the overhead expenses related to operating a medical spa or clinic. March 18, 2023