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- The Exploitation of Polymer Based Nanocomposites for Additive Manufacturing: A Prospective ReviewPublication . Khan, Imran; Kamma-Lorger, Christina S.; Mohan, Saeed D.; Mateus, Artur; Mitchell, GeoffreyAdditive manufacturing (AM) is a well-known technology for making real three dimensional objects, based on metal, ceramic and plastic material used for various applications. The aim of this review is to explore and offer an insight in to the state of the art polymer based nanocomposites in to additive manufacturing applications. In context to this, the developing efforts and trends in nanocomposites development particularly for additive manufacturing processes were studied and summed up. The scope and limitations of nanocomposites into Stereolithography, selective laser sintering and fused deposition modeling was explored and highlighted. The review highlights widely accepted nanoparticles for range of applications including mechanical, electrical, flame retardance and crossing over into more biological with the use of polymer matrices. Acquisition of functional parts with limitations in regard to printing is highlighted. Overall, the review highlights successes, limitations and opportunities that the union of AM and polymer based nanocomposites can bring to science and technology.
- Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon FibersPublication . Reis Silva, Miguel; Pereira, António M.; Alves, Nuno; Mateus, Gonçalo; Mateus, Artur; Malça, C.This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.
- Biomechanically Inspired Shape Memory Effect Machines Driven by Muscle like Acting NiTi AlloysPublication . Raffaella Aversa; Francesco Tamburrino; Relly Victoria V. Petrescu; Florian Ion T. Petrescu; Mateus, Artur; Guanying, Chen; Antonio ApicellaThe research shows a bioinspired approach to be adopted to design of systems based on Shape Memory Alloys (SMAs), a class of Smart Materials that has in common with muscles the capability to react to an impulse (thermal for SMAs) with a contraction. The biomechanically inspired machine that is discussed in the paper refers to the antagonistic muscles pairs, which belongs to the Skeletal Muscles and are normally arranged in opposition so that as one group of muscles contract another group relaxes or lengthens. The study proposes a model, a solution not only to design a specific application, but also to provide an approach to be used for a wide range of adaptive applications (switchable windows, smart shadow systems, parking and urban shelters, etc.), where the shape changes in response to different external stimuli. The use of antagonist pairs mechanism provides a solution for better optimized systems based on SMAs where the main and proven advantages are: Easier and faster change of shape, lower need of energy for system operation, lower cost for SMA training and no problem of overheating.
- Rosin Based Composites for Additive ManufacturingPublication . Sousa, Dora; Biscaia, Sara; Viana, Tânia; Gaspar, Miguel Belbut; Mahendra, Vidhura; Mohan, Saeed D.; Mateus, Artur; Mitchell, GeoffreyRosins are the non-volatile exudates of pine resins with hydrophobic characteristics that are widely used as a precursor for many industrial applications. In this paper we discuss the nature, process and its applications as a matrix for a composite material for additive manufacturing. The composite material has been tailored to chemical and mechanical properties with respect to their applications.
- Large scale additive manufacturing of eco-compositesPublication . Horta, João; Simões, Fábio; Mateus, ArturThe evolution of additive manufacturing processes is enabling the production of parts with improved dimensional accuracy, mechanical, physical and chemical properties [1]. New materials also contribute to this trend, and in this scope, eco-composites, materials with environmental and ecological advantages, which include natural polymers, have been acquiring increased relevance [2]. The purpose of this study is to develop composite material parts manufactured from recycled thermoplastics and natural fibres, in this case, wood residues. Additive manufacturing (fused deposition modelling) will be accomplished using a robot combined with extrusion unit. The objective is to access the influence of the main manufacturing parameters, such as temperature, distance between layers or deposition speed, on the final part characteristics, especially dimensional accuracy. Reverse engineering and several material analysis techniques will be employed to achieve this goal.
- Industry 4.0 - Digital Twin Applied to Direct Digital ManufacturingPublication . Vitorino, João; Ribeiro, Eliseu; Silva, Rúben; Santos, Cyril; Carreira, Pedro; Mitchell, Geoffrey; Mateus, ArturMarinha Grande is a city in Leiria’s district, Portugal. Marinha Grande is known as the moulding city, influenced by the glass, plastic and rapid manufacturing industry. Its history comes from the 18th century with the first glass factory. In order to improve technological development in the local industry, Centre for rapid and sustainable product development (CDRsp) was established in 2007. With that historical know-how and data-based moulding manufacturing, this work goal is to link that data with today’s technology, implementing the Industry 4.0. That information would be stored in a Cloud-Based Design and Manufacturing (CBDM) as well as the real-time operational data. Accessing to that cloud, the design and production engineers can work together to digitally create a product without having to stop the machinery. To implement these concepts, this paper suggests a Digital Twin (DT) to take advantage of the historical information allied to the existent industrial machinery. It suggests a digital twin of a robotic arm with an additive or hybrid manufacturing tool, printing big parts (e.g. garden benches or urban furniture) with reused materials such as tire, cork, wood or stone pow loads.
- High Efficiency Cooling and Heating Channels for Injection MouldingPublication . Freitas, Paulo; Santos, Cyril; Carreira, Pedro; Mateus, ArturFor many years traditional injection moulding has been the norm for obtaining polymer based products, and yet this cycle still shows potential for improvement. This paper will encompass the potential in the thermal part of the cycle, by introducing a novel approach to conventional tubular cooling designs, empowered by additive technologies this reiterates what’s being known as conformal cooling. Different geometries and techniques are compared to determine the optimal cross section layout of the fluid channels and inner surface of the moulding parts. If the cooling achieved is sufficiently fast the crystallographic growth of the material can be manipulated to obtain specific properties observable in the mesoscale. This however can be transversely applied in other heat exchanging structures in future studies.
- Produção de peças biodegradáveis de parede fina por injeçãoPublication . Santos, C.; Mendes, A.; Carreira, P.; Mateus, A.; Alves, N.Actualmente, a indústria dos moldes para responder às exigências do mercado procura diversificar os seus mercados, apostando em produtos diferenciados e de valor acrescentado. Foi neste sentido que se desenvolveu o projecto de concepção e fabrico de vasos biodegradáveis para germinação de plantas. O objectivo deste artigo de investigação passa pela concepção e desenvolvimento de um vaso para germinação de plantas produzido em material biodegradável. A validação do projecto desenvolvido para uma peça de paredes finas em material biodegradável, foi realizada através da fabricação da ferramenta (molde) e o processamento de peças (vasos biodegradáveis). Este estudo demonstrou-se promissor como pilar de apoio para o desenvolvimento de futuros produtos em materiais biodegradáveis de paredes finas, obtidos pelo processo de injecção de termoplásticos. Os resultados alcançados permitiram validar o processo desenvolvido, bem como o produto obtido de paredes finas em material biodegradável, que neste caso foi um vaso biodegradável para germinação de plantas.
- Sobre o cálculo dos ângulos de sopé e de convergência para veículos automóveisPublication . Martins-Ferreira, N.; Gaspar, Miguel Belbut; Mateus, Artur
- Direct Digital Manufacturing and PolymersPublication . Mitchell, Geoffrey; Alves, Nuno; Mateus, Artur Jorge dosPreface: This special issue contains selected papers presented at the second edition of the International Conference on Direct Digital Manufacturing and Polymers held in Marinha Grande, Portugal. The conference is heldbiannually and takes place in India(University of Karnatak)and Portugal(Institute Polytechnic of Leiria)on an alternating basis. In 2017 was held in Marinha Grande, an important industrial area of Portugal and home of the Centre for Rapid and Sustainable Product Development, Institute Polytechnic of Leiria. The conference coincided with the 10thanniversary of the foundation of the Centre and a special celebratory gala dinner was held at the Hotel Mar e Sol. Director of the Centre, Professor Nuno Alvespresented to ProfessorPramod Gai, the Vice-Chancellorthe University of Karnatak, the “International Institutional Collaborator2017” award. Other awardswere presented and the Director, Professor Alves acknowledged the strong support received by CDRSP from the President of the Marinha Grande MunicIpality.
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