F. J. P. Sousa

Estudo da viabilidade de obtenção de isoladores elétricos a partir de resíduo de esmaltação

A gestao racional de residuos industriais e um dos serios problemas da sociedade atual. O presente trabalho tem por objetivo propor uma alternativa para o aproveitamento do residuo de esmaltacao da empresa Portinari, grupo Cecrisa S.A, por meio da utilizacao desse residuo como principal componente em massas cerâmicas para obtencao de isoladores eletricos de distribuicao secundaria. Foram estudadas formulacoes contendo no minimo 50% de residuo e quantidades variaveis de alumina, feldspato potassico e de quartzo. O residuo bruto foi primeiramente beneficiado e submetido as analises quimica, termica e mineralogica para fins de caracterizacao. Adotou-se o processo de conformacao plastica por torneamento para fabricacao das amostras a verde, as quais foram secadas ao ar livre. As amostras obtidas foram submetidas a um ciclo termico previamente indicado pela curva de gresificacao do residuo. Por fim, apos a queima, os prototipos foram ensaiados quanto a rigidez dieletrica. Os resultados indicaram a compatibilidade tecnica dos mesmos considerando o uso como isolador.

Gloss Enhancement Behaviour of Tiles with Different Initial Surface Conditions

This work addresses gloss enhancement by industrial polishing of porcelain stoneware tiles with different initial surface conditions. Tile samples were polished using a laboratory-scale CNC tribometer that properly simulated industrial processing conditions and the results of gloss and roughness evolution were compared with models proposed in the literature. The experimental data showed very good correlation with exponential regression models for situations in which the tiles’ initial surfaces had a fairly homogeneous and stable state in terms of gloss and roughness. For cases where the tiles have less homogeneous surfaces, which is closer to the industrial reality, data analysis showed an evident deviation from the exponential models, which is further discussed in the paper.

Evolution of Wear on the Abrasive Tool during the Polishing of Porcelain Tile Using Morphological Space

Costs with the polishing process represent nearly a third of what costumers pay for polished floor tiles. This is in part due to the high consumption of cemented-matrix abrasive tools, whose demand is about half kilogram per square meter final product. The present study addresses the wear of such abrasive tools, colloquially known as fickerts in the industrial polishing process of ceramic tiles. The focus was set on the evolution of the fickert ́s surface during polishing. The fickert ́s topography was periodically measured by both optical and confocal microscopy. The abrasive tool was submitted to a sequence of ten polishing steps of one second each. All variations were quantitatively characterized and were successfully represented by means of the morphological space. Such space is in turn composed by two statistical parameters: the skewness and kurtosis, both based on the distribution of heights collected from roughness profiles taken along the fickert ́s active surface. The experimental points showed a linear relationship between skewness and kurtosis, in a very good accordance with the behavior expected for typical abrasive wear.

Characterisation of the tool wear during ductile polishing of ceramic tiles using morphological space

The present work is focused on the wear of the abrasive tools during the industrial polishing process of porcelain stoneware tiles, aiming to extend the validity of using morphological space to quantify the wear when very fine abrasive tools are used. In such morphological space, the horizontal and vertical axes are respectively the skewness (Sk) and the kurtosis (K) of the distribution of heights taken from several surface profiles. Despite the existence of an intrinsic interaction between Sk and K, the approach enables the sequence of geometrical changes suffered by the fickert surface to be quantitatively evaluated. The experimental points obtained were nearly aligned and with a negative slope, just as expected for abrasive wear. Implausibly, the results for fine abrasive fickerts was much more scattered than for those with coarse abrasive particles found in literature.

Glanzsteigerungsverhalten von Fliesen mit unterschiedlichen Oberflächen-beschaffenheiten im Ausgangszustand

KurzfassungDiese Arbeit beschäftigt sich mit der Glanzsteigerung durch industrielle Polierverfahren von Feinsteinzeug-Fliesen mit unterschiedlichen Oberflächenbeschaffenheiten im Ausgangszustand. Fliesenproben wurden im Labormaßstab mittels CNC-Tribometer einem Polierverfahren unterzogen, was die industriellen Produktionsbedingungen gut simulierte. Die so erzielten Ergebnisse zur Entwicklung von Glanz und Rauheit wurden mit den in der Fachliteratur vorgeschlagenen Modellen verglichen. Die anhand der Versuche bestimmten Werte zeigten eine hohe Übereinstimmung mit exponentiellen Regressionsmodellen für Situationen, in denen die Ausgangsoberflächen der Fliesen hohe Homogenität und Stabilität in Bezug auf Glanz und Rauheit aufweisen. In den Fällen, in denen die Fliesen eine weniger homogene Oberflächenbeschaffenheit haben, was näher an der industriellen Realität liegt, zeigte die Auswertung der Werte eine offensichtliche Abweichung von den Exponentialmodellen und wird im Folgenden ausführlich diskutiert.AbstractThis work addresses gloss enhancement by industrial polishing of porcelain stoneware tiles with different initial surface conditions. Tile samples were polished using a laboratory-scale CNC tribometer that properly simulated industrial processing conditions and the results of gloss and roughness evolution were compared with models proposed in the literature. The experimental data showed very good correlation with exponential regression models for situations in which the tiles’ initial surfaces had a fairly homogeneous and stable state in terms of gloss and roughness. For cases where the tiles have less homogeneous surfaces, which is closer to the industrial reality, data analysis showed an evident deviation from the exponential models, which is further discussed in the paper.

Effect of Sense and Spacing in Parallel Scratches During Brittle Machining of Stoneware Tiles

Assuming that during the machining of stoneware tiles by flat grinding each grain on the abrasive wheel performs a single scratch, it is possible to simulate and analysis the effect generated by those employing esclerometry. This paper studied the effect between parallel scratches during brittle machining of stoneware tiles. Scratching tests were performed employing a CNC esclerometer; a Vickers indenter as abrasive tool; load of 10N by dead weight; three different configurations of sense in the same direction; three different configurations of spacing between the scratches incremented with a factor of 0.8, 1.0 and 1.2 times the average scratch width. The test samples were analyzed by optical microscopy and subsequent digital image analysis to quantify the worked area. The results showed variation of material removal as a function of the sense and spacing configuration. The sense configuration 1st R-3rd R-2nd R had the highest improve in material remotion. The spacing arrangement 1.2 remain with many not worked areas between the scratches, needing rework to remove this material. The configuration with 0.8 was found a redundancy of work specially when used with the sense configuration of 1st R-3rd L-2nd R.