Structural analysis of the heat affected zone of marble and limestone tiles cut by CO2 laser

Portugal has a long tradition in high quality ornamental stone production, particularly marble and limestone. Quarrying and transformation of these stones are a major value for the Portuguese economy with an important contribution to its GNP. Laser cutting has been investigated to evaluate its potential in ornamental stone processing. This paper presents a report on the structural modifications observed on the cut surfaces produced with CO2 lasers in commercial tiles of calcitic marble and limestone. It was found that marble and limestone can be cut by CO2 laser and the cut surface quality is very much dependent on the chemical and mineralogical compositions of the stone, namely on the chemical composition of calcite and on the degree of crystallinity on the rock.