What is Laser Cutting?
Laser cutting is basically a precise method of carving designs from a given material using a sample given by the client. It involves firing up of laser which cuts by melting, vaporizing or burning the material.
The beam is actually emitted from the laser tube and is reflected back several mirrors into the laser head like a periscope. Inside the head is a lens that focuses the beam onto the surface of the material for cutting or carving. Laser cutting comes into production in 1965 and was initially used to drill holes in diamond mines. Slowly, pioneering work was conducted to cut through different types of metals and carbon dioxide lasers were adopted to cut non-metals.
Types of Lasers:
- Carbon dioxide (CO2) lasers: It is suited for cutting, engraving and boring. They are also applicable for welding operations. They are used for industrial cutting of numerous materials such as titanium, aluminum, fabrics, stainless steel and paper along with other materials.
- Neodymium (Nd) lasers: It is used for boring where there is a requirement of high energy and low repetition cycles are required.
- Neodymium yttrium aluminum garnet (Nd-YAG) Lasers: It is identical to Neodymium lasers but differs in the application. It is used where high power for boring and engraving is required. It can also be operated for welding purposes. These are primarily used for cutting, scribing metals and ceramics.
- Fiber lasers: These are newly evolved solid-state lasers that unlike CO2 utilize solid gain medium as opposed to liquid or gas medium. These have a very small wavelength and hence can produce extremely small spot sizes thereby making it ideal for cutting the metal. It is one of the biggest advantages of fiber over CO2.
Some of the important parameters that can affect the cut quality and when done under controlled medium can result in excellent carving are the maintenance of distance and focal point. Laser cutting quality can be affected by slight raising or lowering of the focal point just above or below or at the surface.
How Does it Work?
- The laser beam comprises of the very high intensity of light of a single wavelength as it travels from the resonator producing a beam that goes through the machine’s beam path.
- The focused laser beam travels through the bore of the nozzle before striking the plate along with either oxygen or nitrogen.
- After focusing the beam towards a focal point, the heat density is intensified at that spot. It will result in rapid melting, heating or partial vaporization of the material.
Apart from this, there are many different methods for engraving via laser cutting of different types to cut through different materials. Some of them require vaporization, melt blow and burn, scribing or burning stabilized laser cutting.
- Vaporization Cutting: In this method, the focused beam heats the material to its boiling point and generates a keyhole that results in the increase of absorptivity and deepens the hole. Non-melting materials such as wood, plastics, and carbon are cut by this method.
- Melt and Blow: It uses high-pressure gas to blow away the molten material and thereby greatly decreasing the power required. Usually, metals are cut using this method.
- Reactive Cutting: It is also called as burning stabilized laser gas cutting or flame cutting. It is like an oxygen torch cutting equipped with a laser beam as an ignition source. It is mostly employed to cut thick steel plates with less laser power requirement.