Diode lasers produce clean seal

17 Jun 2002

High-power diode lasers create a germ-free seal between ceramic tiles.

Laser grouting

A group of researchers from Singapore and the UK has developed a high-power diode laser (HPDL) system that can be used to grout ceramic tiles. The system, developed by the Nanyang Technological University (NTU) in Singapore and the University of Manchester Institute of Science and Technology, UK, produces a permanent and contamination-free seal between the tiles and is suitable for industrial applications (Optics and Laser Technology 34 27).

The researchers have formulated a tough and inexpensive grout material that is suitable for laser glazing. A fiber-coupled HPDL is then scanned across the 1.5 mm gap between ceramic tiles creating a permanent seal with no cracks or porosity in a single-stage process.

The team uses an HPDL operating at 810 nm in continuous wave mode. This type of laser is typically used in medical applications. Using power densities as low as 200 kW/mm² , they have successfully sealed tiles at rates up to 60 cm/min.

Jonathan Lawrence, a researcher based at NTU, told Optics.org that "previous studies have shown this is the most appropriate laser to use in terms of wavelength. It is arguably the only laser that is truly portable and can be used in-situ".

The grout contains a crushed ceramic tile mix acting as a tough, bulk substrate and is specially designed to minimize heat transfer in the tiles and prevent them from cracking. An enamel layer is added to cap the grout and, when the laser is applied, this combination provides an impervious seal.

"The grout material is designed for use with glazed ceramic tiles only. We are working on grouts that can be used in clay quarry tiles, marble and granite tiles," said Lawrence. The team is also hoping to generate seals that are strong enough to be used on floor tiles.

The technique is currently designed for industrial applications but the researchers are exploring the possibility of adapting it for domestic use. Field trials are currently being carried out with a view to commerializing the technique.

Author
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.