Types of Natural Inorganic Materials
Mother of Pearl
All materials have unique characteristics that dictate how the laser beam interacts and consequently modifies the material. The most common processes for natural inorganic materials are the following:
Laser Cutting of Natural Inorganic Materials
The energy of a CO2 laser beam is easily absorbed by natural inorganic materials. The laser beam heats the material directly in its path, causing it to vaporize. However, because natural inorganic materials are brittle, this local heating can cause the material to fracture before the laser beam can cut completely through. If the material is less than 0.010” thick (2.5 mm), the laser beam can cut through the material without fracturing. Mother of pearl is usually thin enough to be laser cut cleanly, with smooth edges and no chipping.
Laser Engraving of Natural Inorganic Materials
The power of the CO2 laser beam can be limited so that it removes (engraves) material to a specified depth. The laser engraving process can be used to create patterns and designs in the surface of natural inorganic materials. Laser engraving can also be used to convey information.
Laser Marking of Natural Inorganic Materials
Most natural inorganic materials can be laser marked using a CO2 laser beam. The energy of the laser beam causes micro-cracks to from on the surface of the material. The micro-cracks scatter light, causing the marked area to appear lighter and brighter than unmarked area. Laser marking can be used to create designs or to convey information.
The laser engraving and marking processes described above can be combined without having to move or re-fixture the material. Only very thin natural inorganic materials can be laser cut. So this process is not usually combined with other laser processes.