CO2 Laser as a Sustainable Alternative for the Mitigation of Sanitary Ware Manufacturing Defects

The development of society through the centuries led to the improvement of healthcare and hygiene conditions throughout the world and, thus, the generalization of ceramic sanitary ware. Indeed, this industry possesses a huge financial impact on the global economy, employing thousands of people worldwide. In spite of their high production levels and increased efficiency, the sanitary ware manufacturing process is still characterized by some defects which make the commercialization of these products unfeasible. Currently, these flaws are rectified by a refiring in the kiln; however the defective parts occupy space intended for new ones to be produced and there is a high chance of new defects arising or the component to break due to the excessive heat of a second firing, hugely increasing the production costs. Accordingly, in this article a sustainable alternative is proposed, using a CO2 laser to repair only the defect area, thus leaving the remaining part untouched. Several laser parameters were tested in experimental tests of two different kinds of defects, using quantitative and qualitative analysis methods, through colour difference reading (with an ANOVA approach), and the optical microscope, SEM-EDS and chemical analyses, respectively. The best results considering defects provoked on a white coloured part were obtained with the manual firing for a laser power between 50 and 70 W, and an interaction time of 1 to 3 firings of 10 s each. These values apply for both pinholes and fissures, with a 50 W power and an interaction of 30 s being the best.