The drilling of slate tiles by a Nd:YAG laser

Abstract

We have undertaken a series of experiments to investigate the feasibility of using a Nd:YAG laser to drill slate tiles. Slate is used primarily as a roof building material after it is split into thin flat layers. The traditional fixation system of slate tiles in Europe consists of clamping the slate pieces by means of metallic clamps and overlapping the different tiles in order to form an impervious roof. An alternative to this clamping technique, is the use of nails to fix the slate tiles to a wooden frame. This method improves the fixation of the slate tiles and reduces the costs related to roof repair by extending the period between maintenance. However, the use of nails requires the production of holes in the slate pieces, which is currently achieved by a mechanical route that results in large holes and an extended manufacturing time. The aim of this work is to explore the capabilities of a pulsed Nd:YAG laser to drill tiny holes in slate tiles in order to produce a better quality drilled slate tile in a reduced time. Shallow holes were produced in slate samples using a 1 kW Nd:YAG pulsed laser focused onto the slate surface by an 80 mm fused silica lens. The results obtained in this study shows the enormous potential of Nd:YAG lasers in the production of slate tiles.