Analytical Determination of the Distribution of Polishing Time over the Surface of Polished Tiles

Abstract

Several kinds of glossiness pattern can be seen on the surface of porcelain stoneware tiles right after the polishing process, as a function of the kinematics performed by the polishing heads. For the newest generation of industrial polishing trains, where a transverse oscillation is included, there is still a great need for literature about the resulting patterns. This paper intends to find the spatial distribution of time under polishing analytically using the kinematics equations involved in the polishing process. The measured values of glossiness collected from three polished tiles are also presented. The importance of adopting a good kinematics for the polishing process has been highlighted, and the equations developed herein are useful tools for further attempts at optimizing the polishing process.

Optimization of the Kinematics Available in the Polishing Process of Ceramic Tiles by Computational Simulations

“…Despite the different values of V and f , points 3 (43; 0.30) and 4 (50; 0.35) have shown the same value of CV=11.1%, and the same polishing pattern, except for some scale difference. According to a previous work, 10 the reason for this is that such conditions have approximately the same ratio V / f =143 mm, which in fact corresponds to the wavelength of the polishing trajectory.…”

“…As mentioned above, due to the resulting motion of the polishing heads, meaningful differences can be observed between the time that each region of the tile surface remains under polishing 2,10 . In other words, according to the kinematics selected for the polishing train, some regions of the tile surface have to undergo a longer duration of polishing than others, so that gloss gradients are generated.…”

“…(1). Further details on this are available in Sousa et al 10 : or: Function f S stands for the sine function performed by the center of the polishing head, designated as point C, which has coordinates X C and Y C . The hollow circle represents the effective work zone of the polishing head, and function f OC∩ represents the top half of the outer circle (radius R ), hence defining the reach of the abrasive blocks, also known as fickerts.…”

“…Thus, a wide range of the possible values inside the domain of both forward speed and transverse oscillation frequency were simulated in order to obtain their respective distributions of polishing time. These results were calculated according to previous studies by the same authors, 5,10 and were organized with the intention of providing a useful and quick guide for industries of the sector of polished tiles. The most recommended kinematics regarding a uniform distribution of abrasive contacts can be found highlighted in specific graphics.…”

Dependence of surface porosity on the polishing depth of porcelain stoneware tiles

“…Recent studies based on the speed and rate of polishing machines have revealed that the oscillations of the transversal and lateral movements of the buffer heads used in the kinematics of the industrial polishing process modify the area of the product's effectively polished surface and its gloss. 6,7 Experiments conducted by ARANTES 8 indicated that the pores in porcelain stoneware tile can be oriented in the pressing stage, showing a porosity gradient along the cross section of the product. This information is not supported by other investigations, but if those findings can occur under determined conditions, it can be concluded that another important variable to be considered is the thickness of the surface layer removed by polishing.…”