A process for manufacturing ceramic tiles

Abstract

A process for manufacturing ceramic tiles by ceramic powder pressing in cavities of a die provided with an isostatic punch a membrane of which rests on oil contained in adjacent and non-communicating chambers in continuous operation, characterised in that it comprises following operations: detection of a density of the powders pressed in a plurality of points n uniformly distributed in each area of a tile which plurality of points corresponds to a chamber of of the punch; performing a calculation of a mean of density readings taken at all the points in each area; comparing read values with a desired optimal density value; removing or, respectively, adding oil to each isostatic chamber of the punch if the mean of densities in the chamber is above or respectively below the optimal density value.

Description

technical field [0001] The present invention relates to a method of manufacturing ceramic tiles by powder compaction and subsequent firing at high temperature. Background technique [0002] The powder, called ceramic powder, intended to be pressed into the cavity of the mould, has a humidity of about 6%, generally comprised between 4% and 8%. [0003] The powder is supplied to the cavity of the die by means of a trolley equipped with a bottomless frame, filled with powder, positioned above the cavity of the die; the lower punch of the die is raised to the level of the upper edge of the cavity. [0004] The punch is then lowered by an amount equal to the thickness of the soft powder to be pressed causing the required amount of powder to fall into the cavity, which is smoothed by the trolley itself as it passes to allow the upper punch to drop. [0005] The cavity of the die contains a lower punch firmly constrained to the die mechanism, and an upper punch firmly constrained ...

AI Technical Summary

Problems solved by technology

[0009] However, there is a further problem arising from the fact that the density completely determines the shrinkage of the tiles, resulting in fired tiles being smaller than unfired tiles

It has been suggested to vary the pressure according to the humidity of the inlet powder, but this system by itself has not proved sufficient to solve the problem, because given equal pressure, the density is not only affected by the humidity, although an isostatic die is used, but the distribution and particle size of the powder is related to the humidity. , that is, parameters that can vary over time in various regions of the mold cavity act synergistically

[0018] The above considerations for molds with a single cavity are further complicated by molds with more than one cavity