Etching is the changing of material surfaces for various purposes, and this can be achieved in many ways, through physical change, through the use of acids and the use of lasers. Laser etching does this by melting the surface of the material that needs to be etched. Lasers deliver a high amount of energy to small areas and this intensity is controlled by its settings.
When a laser beam of the right intensity is delivered to the plastic or metal it causes the material to melt, expand and then resolidify creating crevasses and bumps on the surface. This causes an optical phenomenon that reflects regular light. Small bumps cause the reflected light to be more diffuse and thus appear paler. Deeper crevasses will trap the ambient light and thus appear darker to the persons observing the etched surface.
Laser etching affects material on the surface to a depth of about 0.5 mm equivalent to 20 mils. These depths cause unevenness in the surface that can be felt when touched, and the design or writing can be read with the naked eye, also making them readable to automatic scanners. Materials that can be etched can be steel, aluminum, and many other metals. Laser etching can also be carried out on other materials like plastic or paper.
In a laser, a beam of light is created and amplified to produce a focal point. The light rays of lasers have the same wavelength and lead to a powerful concentration of energy, that allows it to heat and melt metal. Lasers are also used for marking or engraving. Marking creates high contrast marks that do not disrupt the material, whereas in engraving the material is removed to create cavities. In laser etching, high heat from lasers is used to melt the surface of the material to depths that are often less than 0.001 inches. It is this melted material that causes a raised mark after the melted material solidifies.
In laser etching, the surface finish of the materials is changed leading to altered reflectivity that enhances contrast. It can be carried out on metal surfaces that have been plated or anodized. It is also possible to etch ceramic surfaces.
Laser etching is often used to create definite part identification marks that are permanent and can go a long way in reducing errors while increasing safety. It can greatly help in tracing parts so that they are identified when needed.