Laser Cutting Natural Stone

A unique mathematical model to simulate the process of cutting natural stones in rectilinear (straight line) path, by carbon dioxide (CO2) laser, was implemented in a personal computer. The implemented model determined the shape and dimension of the kerf (cut slots or channels) using such variables as the thermo-physical characteristics of the marble, the characteristics of the laser beam and the variables of the process. In the stone processing field it represents an absolutely innovative technology, allowing both cutting as well as surface treatment of the material. The results obtained showed very good agreement with values obtained in the experiments conducted using commercially available CO2 laser.

The natural stone used in the experiments was the famous Royal Perlato of Coreno, which is a marble quarried in the South of Lazio, Italy. It is mainly composed of calcium carbonate (99%) and represents the earliest example of polymorphism (a very long duration natural process) found in natural substances (like carbon's polymorphism into diamonds). Polymorphism is a complex phenomenon which involves both chemical and physical aspects. From a chemical point of view, the substance is defined polymorphism, only if its atoms or molecules can assume two different asymmetrical spatial structures in a condensed state. Polymorphism transforms calcium carbonate molecules into structures called calcite and aragonite due to micro-organisms activity and because of amalgamation of river and sea waters involving an over saturation of calcium carbonate that accelerates its becoming calcite or aragonite.