Percorrer por autor "Sousa, Vitor"
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- Experimental study on the wear behavior of B4C and TiB2 monolayered PVD coatings under high contact loadsPublication . Casais, Rafaela B.; Baptista, António Monteiro; Silva, Francisco J. G.; Andrade, Fátima; Sousa, Vitor; Marques, Maria JoséThere are several ways to characterize the wear resistance of coatings in the laboratory, almost all of them applying relatively low loads, both punctually and more widely. Pin-on-disc, reciprocal sliding, and micro-abrasion wear tests are quite common configurations for this purpose. Thus, a gap was identified in terms of characterization of hard PVD coatings subject to higher loads. This work aims to study and compare the wear behavior of two different coatings obtained by PVD, both monolayer, B4C (boron carbide) and TiB2 (titanium diboride), focused on identifying the wear mechanisms present in different coatings provided with high hardness. Both coatings were initially characterized in terms of chemical composition, thickness, morphology, structure, hardness, and adhesion to the substrate, being subsequently tested in laboratory equipment for wear tests following the block-on-ring configuration and relatively high loads; with a view to study the failure mechanisms of the coatings and their wear rate, it was found that the main wear mechanism, sustained by the analyzed coatings, was abrasive wear in the contact area. In the craters left by the tests, it was determined that the main wear mechanism was two-body abrasion. The B4C and TiB2 coatings performed well in relation to the load and configuration used, in line with the behavior already observed in other used wear test configurations. However, under the imposed conditions, and comparing the two coatings, TiB2 is the best option when high loads need to be applied to the coated surfaces, as these coatings did not suffer perforation during testing and the amount of removed volume was inferior to that of the B4C coated samples.
- Increasing the Sustainability of Manufacturing Processes in Plastic Injection: Recovering Out-Of-Service Robots to Eliminate Manual Assembly OperationsPublication . Costa, Rúben; Sousa, Vitor; Silva, Francisco J. G.; Campilho, Raul; Sá, José Carlos; Pinto, Arnaldo; Pereira, JoãoIn the 20th century, there was a burst concerning the development of the automobile industry, which has become an essential asset for society. With its evolution, this industry created a foundation that based its competitiveness on satisfying people’s needs with the highest possible quality and always respecting the delivery deadlines. With the growth in demand, the improvement of certain processes was needed to achieve the desired production goals, accomplished through automation and robotics, as production and assembly lines increasingly used fully automated processes. In plastic injection lines, production is constant and carried out quickly, so it is desirable to perform component assembly steps that immediately support the output of the injection mould parts. This work consists of adapting an obsolete robotic cell to be implemented in one of the production lines to insert components into the injected parts, replacing labour work. Through a mechanical project and an automation design, the equipment was concluded and is currently in production, fulfilling the necessary requirements and improving the process’ cycle time. This proves that it is possible to recover old equipment, which is able to improve current tasks and common needs in modern industry, increasing the economic sustainability of the processes and saving resources