Objective criterion for evaluation of the quality decoration in ceramic floor tile production prior to the sintering process

Abstract

In the ceramic tile decoration process, the set of variables that can cause hue variation is quite wide and independent of the methodology used in the production. The understanding of the effects of these variables over the final expected result is of great importance to the producers, especially if it could be done before the ceramic tile's sintering stage. The quality of the decoration is linked to the deposited dot shape and its filling with ink. It is proposed in this paper the determination of a 'quality index', comparing the theoretical deposition pattern and a real deposition obtained with samples. Measuring the values of the areas with and without ink, using the statistical tool of the ROC curve, it was obtained the values for sensibility=0.791, specificity=0.830, precision=0.802 and quality index=0.768. The method is intended to be used prior to the sintering step for hue variation control.