Laser cutting produces part shapes by cutting sheet material using an intense laser beam. This cutting method uses a beam of high-density light energy focused through a tiny hole in a nozzle. When this beam strikes the surface of the work piece, the material of the work piece is vaporized.
The process offers low cost for prototype and short runs since no physical tooling are needed. Heat distortion is minimal and typically limited to about 10% of material thickness. Cut parts generally remain flat. Lasers leave minimal burrs.
Cutting with a laser can produce almost any 2D shape including cutouts for parts such as enclosures, cams, brackets, decorative items, holders, mechanisms, etc.
Several materials are applicable. Aluminum can be laser cut but requires a higher power more expensive laser. Stainless steel, plain steel and spring steel are highly suitable. Metals such as copper alloys are difficult due to their ability to reflect the laser light and absorb heat. Many plastics are problematic due to toxic fumes.
YOU CAN CHOOSE BETWEEN THREE BASIC TYPES:
With Sublimation Cutting, the laser beam brings the material to its vaporization point directly (Sublimation). An inactive (inert) cutting gas such as Nitrogen forces the molten material out of the cut. Typical materials are, amongst others, wood and plastic. Thin metals can also be cut in this way.
Flame Oxygen Cutting by contrast, is characterized by the fact that the material is only heated to its ignition temperature. Oxygen is used as cutting gas, so that the material burns and forms an oxide which melts through the additional energy from burning. The cutting oxygen then forces the slag out of the cut. Typical material is, for example, low alloy steel (Mild Steel).
For Fusion Cutting, the material is melted directly by the laser beam. As with sublimation cutting, an inert gas, usually nitrogen, is also used here to force the molten material out of the cut. This process is typically used for alloyed steels (Stainless Steel).
All processes have in common that, because of the narrow focus of the laser beam, the width of cut (kerf width) is very small compared to the other thermal cutting processes. Thus minimum material is melted and the laser energy is used very efficiently. The heat input into the material is thus relatively low so that even small geometries can be cut.
In addition, the cut edge is relatively straight which in all gives very high component accuracy from the cutting process.
This means that laser cutting is used in the most diverse areas, specifically wherever high accuracy for the component geometry and the cut edge is required. The preferred range for steel sheets is up to a material thickness of .75" (20 mm) under certain circumstances up to 1" (25 mm). For this application mainly the CO2 Laser and Fiber Laser are used. For greater thicknesses, laser cutting only makes sense for special applications, more usually other cutting processes (Oxyfuel or Plasma Cutting) are used here.
Plate thickness: .004" (.1 mm) up to 1" (25 mm)
Typical: .20" (.5 mm) up to .75" (20 mm)
· Laser light can be well focused from 1" (25 mm) to .007" (.2 mm)
· Laser radiation: coherent, monochromatic, high energy
· Very high power density (some MW/cm2)
· The light melts or partially vaporizes the material and an additional gas stream blows it away
· High to medium cut quality (roughness)
· Smooth to rough, vertical planes of cut
· Metallurgical perfect surfaces (oxidized) or metallic blank surfaces (high pressure inert gas cutting)
· Low heat input
· High to low cutting speeds
· Hardening within the area of the Heat-Affected-Zone (HAZ) (small)
· Dust as well as UV and IR-radiation
Laser Cutting Type :-
CO2 lasers (gas lasers)
CO2 laser are gas lasers that are based on a carbon dioxide gas mixture, which is stimulated electrically. With a wavelength of 10.6 micrometers, they are mainly suited for working on non-metallic materials and on most plastics. CO2 lasers have a relatively high efficiency and feature a very good beam quality. They are therefore the most widely used laser types.
Suited for the following materials: Wood, acrylic, glass, paper, textiles, plastics, foils & films, leather,stone
Fiber lasers belong to the solid state laser group. They generate a laser beam by means of the so-called seed laser and amplify it in specially designed glass fibers, which are supplied with energy via pump diodes. With a wavelength of 1.064 micrometers, fiber lasers produce an extremely small focal diameter; as a result their intensity is up to 100 times higher than that of CO2 lasers with the same emitted average power.
Fiber lasers are optimally suited for metal marking by way of annealing, for metal engraving, and for high-contrast plastic markings. Fiber lasers are generally maintenance-free and feature a long service life of at least 25,000 laser hours.
Suited for the following materials: Metals, coated metals, plastics
Nd:YAG, Nd:YVO (crystal lasers)
Like fiber lasers, crystal lasers belong to the solid-state lasers. Nowadays, lasers for marking applications are pumped by diodes (in the past by flash lamps). The most common laser types in this category areNd:YAG (neodymium-doped yttrium aluminum garnet) and Nd:YVO (neodymium-doped yttrium ortho-vanadate), named after the doping element neodymium and the carrier crystal. With 1.064 micrometers, crystal lasers have the same wavelength as fiber lasers and are thus also suited for marking metals and plastics.
Unlike fiber lasers, these laser types include the relatively expensive pump diodes, which are wearing parts. They must be replaced after approx. 8,000 to max. 15,000 laser hours. The crystal itself also has a shorter service life than a fiber laser.
Suited for the following materials: Metals, coated metals, plastics, to some extent also for ceramic