Laser cutting uses a high intensity beam commonly using optics to direct the light which vaporizes, melts or burns the material producing a high quality cut edge. This process is used widely in industrial manufacturing, small business, creative industries, medical product marking and crafting companies. The laser optics are used to direct the laser beam generated, commercial lasers for cutting materials use a motion control system to follow a CNC or code of the pattern to be cut onto the material. Laser cutting is used to cut straight cut, or cut highly complex patterns, to very precise depths in the material or product. Their versatility allows cutting of various types materials plastic, wood, textiles, leather, acrylic, paper and polymers because they cut clean edges to micron-level tolerances and do not create heat-affected zones.
The main types of lasers used in laser cutting.
Co2 lasers are suited for cutting, engraving and boring, Co2 lasers are powered by “pumping” which is passing a current through a glass tube containing a gas mix, or using RF (radio frequency energy). The radio frequency method is becoming more popular as typically they last longer than glass tubes.
Neodymium (Nd) and neodymium yttrium-aluminium-garnet (Nd:YAG) lasers are identical but differ in application. Nd is used for boring and where high energy but low repetition is required.
Nd-YAG laser is used where very high power is needed and for boring and engraving. Both Co2 and Nd/Nd:YAG lasers can be used for welding.
Fiber lasers are a type of solid state laser that is rapidly growing within the metal cutting industry. Unlike Co2, Fiber technology utilizes a solid gain medium, as opposed to a liquid or gas. The laser beam produced is then amplified within a glass fiber. With a wavelength of 1064 nanometers, fiber lasers produce an extremely small spot size up to 100 times smaller compared to the CO2 making it ideal for cutting reflective metal material.
- Laser welding This process is effective for products with complex geometries or dissimilar materials that are difficult to join together. Depending on the product, laser welding can be the best process for joining compared to soldering or gluing, especially for connecting plastics and metals. It creates very strong, high-precision welds that can be as small as 0.01 mm and provide repeatable quality.
- Wire Stripping Wire stripping removes sections of shielding or insulation from cable and wire providing electrical contact points making the wire ready for termination. This is a fast that provides precision and process control plus eliminates contact with the wire itself, Stripping can ablate insulation at any point along the wire, enabling high-precision removals.
- Thermal stress cracking Brittle materials are sensitive to thermal fracture, this is a feature exploited by thermal stress cracking. The beam is focused on to the surface causing localized heating and thermal expansion. a crack results that can then be guided by moving the beam. This crack can be moved in order of m/s and this process is usually used in cutting of glass.
- Vaporization Vaporization cutting is where the focused beam heats the surface of the material and generates a keyhole. This keyhole leads to an increase in absorptivity quickly deepening the hole. As the hole deepens and the material boils, vapor generated erodes the molten walls blowing ejecta out and further enlarging the hole. Non melting materials such as carbon, wood, delrin and thermoset plastics are normally cut by this method.
Remote Cutting The high intensity laser beam partially vaporises the material, enabling very this sheet material to be cut without the need for an assist gas blown onto the surface.
Fusion cutting This uses an inert gas typically nitrogen that blows the molton material out of the cutting area reducing the power required by the laser beam, as the material heats up and melts the gas blows it out.
Flame or reactive cutting The assist gas is oxygen this is blown onto the cutting area at high pressure, as the oxygen begins to burn and oxidise the reaction creates more energy and assists the laser beam.
Laser cutting offers several advantages over other fabrication processes, it has the ability to customise products or materials, with reduced material production times and contactless cutting. There is no need for complex custom designed tooling, it produces high accuracy with flexibility and is cost effective process. As this is a non contact process the damage to the material surface is minimised allowing for high-quality cutting which on many material do not require secondary cleaning, finishing or treatment saving time and money. Repeatable high quality results are achieved with the entire process controlled by computer programs that use nesting software to reduce the amount of work, production time and waste material produced. The laser generator and external optics require cooling, waste heat may be transferred by a coolant or directly to air. Water is a commonly used coolant, usually circulated through a chiller or heat transfer system. Laser cutting requires a jet of air to be blown onto the material called air assist this prevents flare up and removes any debris from the cut.
New Laser Applications
Lasers are key pieces of equipment for industry, research is being conducted on how to use them more efficiently in manufacturing processes, to speed up processing time. The National Institute of Standards and Technology (NIST) created a laser that pulses 100 times faster than conventional ultrafast lasers. Scientists in Germany are experimenting with integrating tiny lasers directly in silicon chips to increase processing speed.
Research is being conducted using artificial intelligence (AI) to create smart lasers that “understand” the material being processed and when the process is finished. Trumpf a laser machine manufacturer is working on developing a laser system that uses AI to determine the best welding points for creating copper coils for the automotive industry. As more companies embrace industry including AI, sensor technologies, and additive manufacturing, lasers will have an ever-expanding role in modern manufacturing creating new processes, to reduce production times and increase efficiency and lower the carbon footprint for product production and material processing .