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- DMLS technology for automotive toolingPublication . Leal, R.; Barreiros, Fatima; Alves, M.L.; Romeiro, F.; Vasco, J.; Santos, M.; Marto, C.The automotive industry is challenged every day, with companies competing and developing new models and facelifts in short term, requiring new tools or tool reshaping. Concerning the current world economic scenario, decreasing time-for-tooling becomes as important as decreasing time-to-market. Such scenario opens up the horizons for new manufacturing approaches like additive manufacturing. In this case-study, additive manufacturing is applied for tooling up a stamping process for the production of body panels for the automotive industry. This approach enables the manufacturing of stamping tool inserts with similar high performance alloy steel as in conventional tooling, although, without any loss of tool properties and saving a significant part of the tool manufacturing time. The evaluation of the tool performance and tool life estimation was carried out based on three point bending fatigue tests using specimens manufactured by the same additive process and using the same powder material. From these data, it was possible to establish realistic scenarios for the use of additive tooling and to evaluate its feasibility on the automotive industry.
- On the formability, geometrical accuracy, and surface quality of sheet metal parts produced by SPIFPublication . Alves, Maria; Silva, M. B.; Alves, L. M.; Martins, P. A. F.; Xiaoyuan He; Huimin Xie; YiLan KangConventional sheet metal forming processes are not suitable for flexible small-batch production and, therefore, are not appropriate for the growing agile manufacturing trends requiring very short life-cycles, development and production lead times. In fact, the present need for flexible sheet metal forming techniques requires the development of innovative technological solutions that are capable of reducing the fixed and capital costs of sheet metal forming to a level where small-batch production becomes economically feasible. Single point incremental forming (SPIF) is a new sheet metal forming process with a high potential economic payoff for rapid prototyping applications and for small quantity production. In general terms a typical SPIF set-up makes use of a small number of low cost active tools components; (i) a blankholder, (ii) a backing plate and (iii) a single point forming tool. The tool path is generated in a CNC machining center and during the process there is no backup die supporting the back surface of the sheet. Despite the contributions of many researchers on the development of industrial applications and better characterization of the forming limits of the process, several key topics related to the mechanics of deformation, likely mode of failure, geometric accuracy and surface quality of the formed parts remain little understood and scarcely systematized. This paper attempts to provide new contributions about the abovementioned issues by means of a comprehensive experimental investigation performed under laboratory controlled conditions.
- Study of Laser Metal Deposition (LMD) as a Manufacturing Technique in Automotive IndustryPublication . Quaresma Ramalho, Francisco Miguel; Alves, M.L.; Correia, M. S.; Vilhena, L. M.; Ramalho, A.The last few decades in the automotive industry have been marked by a heavy concern with the environment, saving energy and reducing material wastage, while aiming to maintain good mechanical properties, essential in the components usage. Additive manufacturing (AM) techniques present themselves as a viable option in the matter, with Laser Metal Deposition (LMD), rising as one of the most promising techniques within this category, capable of producing near-net shape components, with a layer upon layer construction of three-dimensional solid parts from a 3D CAD model, with good mechanical properties and acceptable surface finishing. Laser Metal Deposition is a relatively recent technique, which is made noticeable by the lack of clarification about the influence of several parameters in the final components characteristics, ultimately leading to a scarce availability of the process in the market. This paper aims to clarify and evaluate, how LMD produced parts can suit the automotive industry, by measuring and analysing their behaviour under several mechanical tests. These mechanical tests have specific focus on wear and abrasion behaviour, as well as elastic properties determination, as these are the characteristics that allow a better overview over the expected performance of LMD components for automotive applications.
- Morphology and Thermal Behaviour of New Mycelium-Based Composites with Different Types of SubstratesPublication . Alves, Rafael M. E.; Alves, M.L.; Campos, Maria J.The need for new green and sustainable materials has been fostering the development, research and introduction of biodegradable materials from natural and renewable sources. Commercially available biodegradable plastics, while minimizing their environmental impact and exhibiting a set of properties that enable the obtainment of industrial components, usually require complex processing methods, are costly and have limited applicability. A new growth of natural resources based paradigm applied as production process is increasing its relevance as an alternative production process. New materials that combine fungal mycelium with waste materials as coffee grounds or wood waste can be considered as promising to fulfill this new paradigm. This new biomaterial mycelium based composites present controllable and adjustable properties during their growth, being able to grow and penetrate organic substrates, thus forming a tangle of branched fibers and a structure that presents some thermo-mechanical properties similar to the ones of plastics. The aim of the present study was the selection of the optimal inoculation temperature, light, humidity and the best substrate for the fastest and consistent mycelium growth. Four types of mycelium were incubated, namely Pleurotus ostreatus (382), Hypsizygus ulmarius (420), Ganoderma lucidum (560) and Trametes versicolor (620). The influence of the three substrates (coffee grounds, pine waste and general wood waste) on the growth was analyzed both morphologically and thermo-mechanically by means of differential scanning calorimetry (DSC) and X-ray micro computed tomography (microCT).