Identificação das variáveis que ocasionam a variação de tonalidade utilizando a técnica de decoração por cilindros de silicone gravados a laser
Abstract
A major problem in the production of ceramic tiles for coating is the variation of
tonality. The determination of their origin within the entire production process and to
minimize its occurrence by the manufacturer is essential. In 2014 the production was
903.3 million square meters, with an estimate production for 2015 of 969.3 million
square meters, which justifies studies of varying shades in production lines ceramic
tiles. For the execution of this work, some variables will be fixed without any loss in
accuracy of the results to be obtained, if only because some of them are already
inherent in the product development flow: ink (formulation); type of glaze and
engobe, decorating cylinder characteristics (type of silicone, incisions, cylinder size),
basic design, set-up decoration equipment and operating condition. The variables
studied were: Density and viscosity of silkscreen ink; Temperature of the ceramic
carrier; Production speed; Cylinder pressure on the tile; Blade Pressure on the
cylinder; Blade angle of attack and support surface humidity. It was observed that the
variables density and viscosity; Decorating speed and variation of blade height on the
cylinder are the variables that most affect the tone variation factor within a
production. For the three cases studied, none of the incisions resulted in filling and
form an ideal decorated dot regarding to the expected geometry and desired for an
ideal decoration (spherical points or ellipse) in any of the tested variables. In all
cases there is a maximum point reached by the variables studied, which gave a
better discharge and consequently a better decoration. In each tone range studied
there is a combination of variables which best accomplishes the deposition points on
the enamel.