Discuss industrial applications of laser.
Answers
Lasers in Industry
Lasers are used in industry in a huge variety of applications. These applications can be divided between those that involve the processing of materials and all other applications. Materials processing includes cutting, drilling, welding, etc., and generally involves the use of high-powered lasers.
Materials Processing
The advantages of using lasers in materials processing include:
there is no contact tool required, unlike normal machining in which the tool bit must be sharpened and often replaced.
brittle or very pliable materials that are very difficult or impossible to machine with tools can be processed using lasers. In fact, one of the first materials processing applications of a laser in the 1960's was to make the holes in rubber baby bottle nipples, a difficult task to do otherwise with drilling.
using fiber optics, access to previously inaccessible locations is available.
laser processing is easily automated to allow computer and robot control.
new types of processing has and continues to be developed, including producing new surface alloys and hardening of materials.
Some of the problems with using lasers for processing include:
certain tasks, such as drilling large diameter holes, are difficult to accomplish with lasers, as we will see.
lasers and optics work best in clean and vibration-free environments, often difficult to achieve on the manufacturing floor.
initial costs can be large and so laser systems have been limited to large industry
Let's now discuss how a laser interacts with materials differently as the laser power is increased (see the figure below). At low power, the surface of the material gets heated, depending on the material properties for absorption and conduction of heat. A mirror clearly reflects most of the light, while a dull black surface absorbs most of the light. Better conductive properties means that the heat will flow more quickly and the local temperature will not get as hot. When the laser power increases sufficiently to increase the temperature enough, the surface begins to melt, turning from solid to liquid. If the power is considerably higher, the material may directly vaporize, the surface atoms turning to a gas. At even higher powers these gas molecules that form become ionized to form what is known as a plasma, a cloud of charged ions. At this point, the efficiency dramatically drops because the plasma begins to block the incident laser beam.