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Authors
Advisor(s)
Abstract(s)
A presente dissertação foi desenvolvida no âmbito da unidade curricular
Dissertação/Estágio, do Mestrado em Engenharia Química, ramo de Qualidade, do
Instituto Superior de Engenharia do Porto. O estágio realizou-se na empresa AQUITEX
– Acabamentos Químicos Têxteis, S.A e teve como principal objetivo a criação de uma
base de dados de forma a incluir dois tipos de pastas cerâmicas, de grés e de faiança.
O processo de desenvolvimento do trabalho consiste em duas etapas, a realização dos
ensaios práticos (pesagem, vidragem e cozedura das peças), tanto para a criação da base
de dados, como para o controlo de qualidade das amostras e a fase da implementação do
método espetrofotométrico.
O método desenvolvido teve por base o sistema de medição de cor CIELab, recorrendo
ao espetrofotómetro X-rite Color i5, da Neurtek Instruments. Para a leitura das amostras
foi utilizado o iluminante D65 (luz do dia média), sendo este pré-definido pelo sistema.
Foram criadas duas bases de dados, para as pastas de grés e de faiança. Para a pasta de
grés foram definidas cinco bases, sendo estas, branco mate, branco reativo, branco mate
reativo, mate e transparente brilhante. E para a pasta de faiança foram utilizadas duas
bases, transparente brilhante e opaco brilhante. Para todas as bases, fez-se variar as
concentrações dos corantes mais utilizados, para valores de 0,5 %, 1 %, 1,5 %, 2 %, 2,5
%, 3 %, 3,5 %, 4 % e 5 %., num total de 13 corantes.
Para o controlo de qualidade das amostras de produção foram definidos os parâmetros de
avaliação da cor ∆E*, sendo o respetivo valor limite de aprovação igual a 2 unidades, L*,
a*, b*, ∆L*, ∆a*, ∆b*, Opacidade e Gloss. Foi realizada a avaliação da conformidade de
320 amostras de vidrados em grés e 303 amostras de vidrados em faianças. As
formulações, através da leitura do PANTONE e da leitura da cor das peças cerâmicas,
permitem verificar a eficiência da implementação do método espetrofotométrico. No
entanto, a formulação que foi realizada necessita de ser corrigida, mas por falta de tempo,
terá de futuramente se realizar a correção desta cor.
This dissertation was developed as part of the Dissertation/Internship course of the Master's Degree in Chemical Engineering, Quality branch, at the Instituto Superior de Engenharia do Porto. The internship took place at the company AQUITEX - Acabamentos Químicos Têxteis, S.A. and its main objective was to create a database to include two types of ceramic pastes, stoneware and earthenware. The process of developing the work consisted of two stages: carrying out practical tests (weighing, glazing and firing the pieces), both for creating the database and for quality control of the samples, and implementing the spectrophotometric method. The method developed was based on the CIELab color measurement system, using the X-rite Color i5 spectrophotometer from Neurtek Instruments. The illuminant D65 (average daylight) was used to read the samples, which was predefined by the system. Two databases were created for the stoneware and earthenware pastes. For the stoneware paste, five bases were defined: matt white, reactive white, reactive matt white, matt and glossy transparent. For earthenware, two bases were used: transparent glossy and opaque glossy. For all the bases, the concentrations of the most commonly used colorants were varied to values of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% and 5%, for a total of 13 colorants. For the quality control of the production samples, the following parameters were defined: color ∆E*, with a limit value of 2 units, L*, a*, b*, ∆L*, ∆a*, ∆b*, Opacity and Gloss. A conformity assessment was carried out on 320 samples of stoneware glazes and 303 samples of earthenware glazes. The formulations, through the PANTONE reading and the color reading of the ceramic pieces, allow us to verify the efficiency of the implementation of the spectrophotometric method. However, the formulation that was made needs to be corrected, but due to lack of time, this color will have to be corrected in the future.
This dissertation was developed as part of the Dissertation/Internship course of the Master's Degree in Chemical Engineering, Quality branch, at the Instituto Superior de Engenharia do Porto. The internship took place at the company AQUITEX - Acabamentos Químicos Têxteis, S.A. and its main objective was to create a database to include two types of ceramic pastes, stoneware and earthenware. The process of developing the work consisted of two stages: carrying out practical tests (weighing, glazing and firing the pieces), both for creating the database and for quality control of the samples, and implementing the spectrophotometric method. The method developed was based on the CIELab color measurement system, using the X-rite Color i5 spectrophotometer from Neurtek Instruments. The illuminant D65 (average daylight) was used to read the samples, which was predefined by the system. Two databases were created for the stoneware and earthenware pastes. For the stoneware paste, five bases were defined: matt white, reactive white, reactive matt white, matt and glossy transparent. For earthenware, two bases were used: transparent glossy and opaque glossy. For all the bases, the concentrations of the most commonly used colorants were varied to values of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% and 5%, for a total of 13 colorants. For the quality control of the production samples, the following parameters were defined: color ∆E*, with a limit value of 2 units, L*, a*, b*, ∆L*, ∆a*, ∆b*, Opacity and Gloss. A conformity assessment was carried out on 320 samples of stoneware glazes and 303 samples of earthenware glazes. The formulations, through the PANTONE reading and the color reading of the ceramic pieces, allow us to verify the efficiency of the implementation of the spectrophotometric method. However, the formulation that was made needs to be corrected, but due to lack of time, this color will have to be corrected in the future.
Description
Keywords
CIELab Ceramics Coatings Glazes Spectrophotometry Stoneware Earthenware Terracotta