Fundamentals of Laser Technology
List of Laser Processes
Lasers are playing an ever-expanding role in material processing, from new product development to high volume manufacturing. For all laser processes, the energy of a laser beam interacts with a material to transform it in some way. Each transformation (or laser process) is controlled by precisely regulating the wavelength, power, duty cycle and repetition rate of the laser beam. These laser processes include the following:
The energy of the laser beam heats the material directly in its path causing it to undergo a phase change (for example, from amorphous to polycrystalline).
The energy of the laser beam rapidly heats and vaporizes the material directly in its path. To create a laser cut, the laser beam energy must be sufficient to penetrate the entire thickness of the material.
Similar to laser cutting. However, the laser beam motion is controlled to create a single hole, or an array of holes, rather than a continuous cut path.
The energy of the laser beam is controlled to vaporize the material directly in its path to a prescribed depth, without penetrating the thickness of the material.
This process is synonymous with laser engraving.
The processes of laser cutting, engraving and drilling are used to create a finished part without using mechanical tools with conventional cutting blades.
The energy of the laser beam is controlled to heat the material directly in its path to modify the surface of the material in a manner that changes its appearance with respect to the surrounding material (for example, surface oxidation or surface bleaching).
The processes of laser cutting, engraving and drilling are used to create a finished part with microscopic features, without using mechanical tools with conventional cutting blades.
Laser perforating uses the laser to drill a series of holes along a continuous path. Laser perforating allows a laser cut shape to remain attached to the original sheet of material and allows it to be detached easily when needed.
Laser Photo Engraving
Image processing software (such as 1-Touch™ Laser Photo) is used to convert a photograph to a bitmap that can be laser engraved into the surface of the material.
Laser Photo Marking
Image processing software (such as 1-Touch™ Laser Photo) is used to convert a photograph to a bitmap that can be laser marked onto the surface of the material.
Laser scoring is using the laser to engrave in a continuous path (often a straight line). Laser scoring is often used to create a seam in thin materials to allow them to be folded easily.
Laser energy is used to heat a powdered metal or ceramic to form a solid film. The laser beam energy is controlled so that the surface of each powder grain melts and fuses to the surface of the adjacent grain. The laser sintering process can be repeated multiple times to create 3-dimensional shapes.
Laser Surface Modification
The energy of the laser beam is controlled to heat the material directly in its path to modify the surface of the material.
Selective Laser Ablation
The energy of the laser beam heats and vaporizes the top layer of a multilayer material, without affecting the underlying material. The laser wavelength must be chosen so that it is absorbed by the top layer, and reflected by the underlying material (for example, ablating paint from metal with a 10.6 microns CO2 laser).
Environmental, Health & Safety Considerations for Plastic Laser Material Processing
Laser-material interactions almost always create gaseous effluent and/or particles. The effluent will include various volatile organic compounds (VOCs) and should be routed to an exterior environment. Alternatively, it may be treated with a filtration system first and then routed to an exterior environment. Plastics that contain chlorine, such as PVC, should never be laser processed. Plastic combustion is inherent to laser processing and may produce flames. Therefore, plastic laser material processing should always be supervised.