Production Speed and its Influence on Hue Variation on Tiles Decoration Based on Silicon Cylinder Technique Laser Engraving Method Fabio Ferraço 1,a , Anselmo Ortega Boschi 1,b , Ana Gabriela Storion 2,c 1 Universidade Federal de São Carlos – UFSCar, DEMa Rodovia Washington Luís, Km 235, 13565-905, São Carlos/SP, Brazil. 2 Universidade Federal de Alfenas – UNIFAL Rodovia José Aurélio Vilela, BR 267, n. 11999, 37715-400, Cidade Universitária Poços de Caldas/MG, Brazil a fbferraco@uol.com.br, b daob@ufscar.br, c gabiags@hotmail.com Keywords: ceramic tile decoration, hue variation, silicone cylinder, laser engraving. Abstract. On the ceramic tile production there are plenty of different possible origins inside the process that can lead to hue variation. Many tile producers use to increase the speed of production and the machinery industry follow this tendency to please their costumers; and so this scenario creates a need of a study on the influence of the speed production on hue variation. In this work this influence was verified using the silicon laser engraving method, one of the most methods worldwide used. Introduction Hue variation is one of the most critical problems on ceramic tiles production. This hue variation, if it is present, can be easily seen after the installation on floor or wall covering, and for the costumer it is undesirable. So the constancy of color characteristics is a producers concern because it diminishes the product quality. The major volume of ceramic tiles production in Brazil is held with machines that uses silicon cylinder laser engraved. In this particular method, the hue variation is connected to the shape of the decorate dots and the volume of ink discharged by the alveolus created by the laser beam. The ideal shape of the alveolus should be round but as the drawing is transferred to the cylinder, it spins below the engraving head, an so, the real shape of the alveolus is elliptical.[1] If all the ink volume is discharged from the alveolus to the glaze surface, it will spread and make a perfect full round hub cap, meaning that the final tile hue will be the pre desired one. On the other hand if this dot is formed by a partial volume of discharged ink, neither the shape nor the volume of ink will be enough for the tile to obtain the ideal final hue. Many authors have studied the influence of cylinder types, different decoration machines, operational methods, glazes, inks, etc. [2, 3] The influence of speed production in this method of decoration is strongly connected to the volume of discharged ink by the alveolus and so forth on the achievement of the ideal tile hue, because an ideal discharge depends on the contact time between the tile and the cylinder. The objective of this work was to study the effect production speed increase on the shape of printed dots, ink volume discharge and the final hue of the surface covered area by the decoration. Materials and methods Some of the process variables regarding to the decoration process were held fixed for the experiment: ink formulation, engobe and glaze coating and type of supports (dry route), type of cylinder (type of silicon, dimensions, engraving and base drawing) and angle and pressure of the steel blade. Materials Science Forum Submitted: 2016-03-07 ISSN: 1662-9752, Vol. 869, pp 136-140 Accepted: 2016-06-21 doi:10.4028/www.scientific.net/MSF.869.136 Online: 2016-08-31 © 2016 Trans Tech Publications, Switzerland All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (#73298261-26/01/17,13:17:45)