Percorrer por autor "Fernandes, Nuno O."
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- Improving the Machining Process of the Metalwork Industry by Upgrading Operative Sequences, Standard Manufacturing Times and Production Procedure ChangesPublication . Monteiro, Carlos; Ferreira, Luís Pinto; Fernandes, Nuno O.; Silva, F.J.G.; Amaral, IvoManufacturing industries are currently experiencing important changes towards digitization and autonomous production control, which is known as Industry 4.0. However, the profitability of some companies, namely Small and Medium Enterprises (SMEs), and of some industrial sectors does not allow for great investments, meaning that is necessary to undertake simple changes that potentially can lead to significant gains. This is the case for the metalwork company under study, where wastes related to the large parts movement and non-conformities detected before and after the parts delivered to the customers have been identified. The elimination of these wastes can contribute to a significant increase in the profitability of the company. The use and integration of several Lean tools made it possible to achieve this goal for this company. Amongst other improvements on productivity and waste reducing, a 59% reduction in the time required to move parts of up to 1000 kg, a reduction of 2.04% on the external non-conformities (i.e. on non-conformities detected outside the company) and 3.99% on the internal non-conformities, was achieved.
- Improving the Machining Process of the Metalworking Industry Using the Lean Tool SMEDPublication . Monteiro, Carlos; Ferreira, Luís Pinto; Fernandes, Nuno O.; Sá, José Carlos; Pereira, Maria Teresa Ribeiro; Silva, F.J.G.The project here presented was developed in a metalworking company, where several areas requiring improvement were identified. The study addresses the elimination of waste and increase of productivity in the machining sector of the company. To this purpose key processes were identified and mapped using flowcharts and VSM (Value Stream Mapping). Achieved improvements involved decreasing setup times by resorting to the lean tool SMED (Single Minute Exchange of Die). Setup times were reduced in 40% on the vertical milling machine of the company, and in 57% on the horizontal milling machine.
- POLCA Control in Two-Stage Production SystemsPublication . Fernandes, Nuno O.; Thürer, Matthias; Mirzaei, Nima; Ferreira, Luís Pinto; Silva, Francisco J. G.; Carmo-Silva, SílvioPOLCA (Paired-cell Overlapping Loops of Cards with Authorization) is a decision support system for material flow control under Quick Response Manufacturing. It operates in the context of low-volume, high-mix, and cellular manufacturing. While there is an increasing literature on POLCA performance, current studies usually assume full availability of components (or parts) at assembly stations, neglecting parts manufacturing and feeding. Therefore, this study uses simulation to assess POLCA performance in a two-stage production system, where at the first stage parts are manufactured and at the second, they are assembled into end-products. The study demonstrates that using POLCA to control both production stages, manufacturing and assembly, significantly outperforms the use of POLCA at the assembly stage only, leading to important reductions of the total throughput time of orders and on the percentage of tardy orders. Statistical analysis of our results was conducted using ANOVA.