Glossiness distribution over the surface of stoneware floor tiles due to the polishing process

The industrial process for polishing floor tiles requires several polishing stages in order to produce the desirable glossiness. Works on floor tile polishing with focus on the distribution of glossiness still lack in literature. The present work intends to measure and analyze the distribution of glossiness over the surface of porcelain stoneware tiles polished using forward speed of 7.5 cm s−1 and lateral oscillation frequency and amplitude of 0.2 s−1 and 12 cm. The glossiness pattern generated by the polishing process over the surface of six tiles were presented in grey-scale graphics, where each pixel was univocally associated with a portion of the tile surface. Correlations between the glossiness pattern found and the polishing kinematics were developed. Significant differences of glossiness were registered either between tiles polished under the same polishing condition, or within the surface of the same tile, between adjacent regions. The use of lateral oscillation motion caused the glossiness pattern over the tile surface to follow a waveform pattern, and two corroborative hypotheses were made in order to explain such fact, considering the light-surface interaction as well as the overlapping of trajectories of adjacent polishing heads.