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Browsing by Author "Correia, A.I."

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  • Cost reduction and quality improvements in the printing industry
    Publication . Moreira, A.; Silva, F.J.G.; Correia, A.I.; Pereira, Maria Teresa; Ferreira, Luís Pinto; Almeida, F. de
    Competitiveness has been the key factor for the survival of the companies. The economic crisis that marked the beginning of this millennium forced the total readjustment of processes and operations which, in some cases, gave origin to deep changes in the organizations. In addition, concerns and consequent environmental constraints have begun to increase. Printing industry was strongly influenced by these factors. This study aims to reduce the use of toxic products and general costs in offset printing process, as well as promote a productivity increase in the printing industry. Because this kind of industry is largely influenced by weather conditions, historical data was collected, allowing to reach the balance between the printing consumables usage and working methodologies, leading to implementing important improvements. At the end of the study, it was possible to observe very good results, increasing the Overall Equipment Effectiveness (OEE) and the Mean Time Between Failure (MTBF) and reducing the Mean Time To Repair (MTTR) relatively to the equipment. The biggest achievement was the massive reduction of the isopropyl alcohol consumption in the offset printing process, increasing the air quality at the facilities, reducing the costs and most of the problems during the printing process.
    2018Journal article Open access Show more
  • Study On The Optimization Of TheTextile Coloristic Performance Of The Bleaching Process Using Pad-Steam
    Publication . Tavares, C.; Silva, F.J.G.; Correia, A.I.; Pereira, Maria Teresa; Ferreira, Luís Pinto; Almeida, F. de
    Information concerning the critical variables of the bleaching process (transformation of a raw fabric into bleached) by pad-steam is scarce, since it is considered a recent process in the textile industry. One hundred percent fine cotton fabrics present great difficulties in the standardization of bleaching across different production batches, which is even more complex when the fabric composition provided by the supplier is unknown. Thus, one carried out an evaluation of the variables that influence color yield in the bleaching process by pad-steam. The conditions used consisted of the reintroduction of the process of desizing by pad-batch, as well as washing and bleaching by pad-steam. The other variable changed was the chemical recipes (desizing and bleaching). As result of this research, the variables which most influenced color performance were the degree of whiteness (Berger) and the pH of extraction. Hence, a change in the production process for this type of 100% fine cotton is required. In this work, a statistical control was performed on the characteristics of the product obtained, which compared results before and during the study. The suggestions for improvement, some of which have already been implemented, are also presented. The results were then compared, enabling one to observe a significant improvement.
    2018Journal article Open access Show more