Laser surface blasting of granite stones using a laser scanning system

Granite stones are the most abundant rock of the crust. Due to their beauty, durability, and virtually zero maintenance, they have been used widely since ancient times in all types of construction, as a structural or decorative element. Commonly, this material is used with a polished finishing, but there has been an increased interest in giving it a rustic aspect, mainly for decorative or functional reasons, e.g., to reduce slipping. Rough surfaces are usually produced by means of bush hammering, but this is an extremely noisy and inefficient process. In this work we have explored the capabilities and limits of a laser blasting process assisted by a scanning system in order to produce precise and controllable roughness on two varieties of granite plates. It was found that laser blasting of thin granite tiles can be accomplished with processing widths up to 250 mm at medium-low laser power, obtaining a rustic aspect suitable for use in façades, paving, or flooring. Moreover, laser scanner systems are capable of enhancing the productivity of this process up to ten times greater than that found in previous works.