Applied Mechanics and Materials Vol. 890

Abstract: The interest around the additive manufacturing is increasing, with more and more solutions at both the industrial and desktop levels. As this is still a relatively recent issue for several industrial areas, there is a clear opportunity to explore in order to optimize the systems in the face of the needs of these same industries, and with increasing times, there are increasing factors to take into ac- count in initial phases of new product development. Presently, there is also a growing ecological awareness, with the concern of implementing a logic of waste reduction and implementation of the circular economy in new products with a view to the valuation of new alternative materials. With the development of solutions aimed at the optimization and feasibility of large additive manufacturing systems, the introduction of new alternative materials will be a reality, presenting in this article a solution and methodology for future tests for new materials. Thus, herein is studied a way of responding to both problems, new ecological materials and BAAM system optimization, presented through a hybrid and flexible solution based on the Pin Bed Forming principle applied to Big Area Additive Manufacturing systems.

Abstract: Additive manufacturing technologies have evolved from prototype to part production. Coupling this shift with organizational transformations evolved rapid prototyping industry into Direct Digital Manufacturing (DDM) industry. Any evolution in production systems is now, more than ever before, dependent on sustainability principles. The development of the DDM industry must be guided by these principles, taking the chance it offers to change the production paradigm. Circular Economy (CE) is a shift in the production and resource management model, and one of the ways to work towards sustainability. Coupling DDM with CE principles is thus contributing to change industrial production to a more sustainable one. This paper intends to relate DDM technologies with CE principles, to identify aspects where DDM is contributing to CE, as well as aspects that should be explored further for that purpose. It is observed that DDM can enable optimization of material and energy usage, modify logistics towards de-localized production and recycling and enable prolonged lifespan of products through better access to spare parts, for instance. It is also observed that DDM has good potential to shift materials usage towards natural materials, especially in a context of consumer or local community production, but not so much within the current industrial context. Education is shown to play a pivotal role, since incorporating circular economy principles in educational contexts should spark a shift in consumer perspectives, modifying demand and hence, industrial production.

Abstract: The additive manufacturing of multimaterial parts, e.g. metal/plastic, with functional gradients represents for current market demands a great potential of applications [1]. Metal Polymer parts combine the good mechanical properties of the metals with the low weight characteristics, good impact strength, good vibration and sound absorption of the polymers. Nevertheless, the coupling between metal and polymers is a great challenge since the processing factors for each one of them are very different. In addition, a system that makes the hybrid processing - metal/polymer - using only one operation is unknown [2, 3]. To overcome this drawback, a hybrid additive manufacturing system based on the additive technologies of SLM and SL was recently developed by the authors. The SLM and SL techniques joined enabling the production of a photopolymerization of the polymer in the voids of a 3D metal mesh previously produced by SLM [4]. The purpose of this work is the study on the metal/polymer interface of hybrid parts manufactured from the hybrid additive manufacturing system [5]. For this, a core of tool steel (H13) and two different types of photo-polymers: one elastomeric (BR3D-DL-Flex) and another one rigid (BR3D-DL-Hard) are considered. A set of six samples for each one of metal core/polymer combination was manufactured and submitted to tensile tests.

Abstract: For 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.

Abstract: Marinha 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.

Abstract: This work is concerned with 3D printing. It's main goal is to establish a conceptualsetting in which the theory of 3D printing can be developed. Following the analogy that aUniversal Turing Machine, in a veryprecise and specific way, computes everything that is computable, we propose to the development for the notion of a Universal PrintingMachine. It is an abstract notion that will simulate any 3d printer, either in existence or to be invented. In theory, it canproduce anything which can be printed. In other words, we areproposing to develop a theoretical model of a 3d printer which will serveas a reference to the current and future developments in the area.

Abstract: Rosins 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.

Abstract: Rosin is the non-volatile exudate of pine resin with hydrophobic characteristics that are widely used and modified as a precursor for many industrial applications such as paints, inks and adhesives. The review paper discusses the rosin, its nature, processing, production material development for green science. The composite materials have been designed and tailored with respect to desired applications to offer a potential replacement of petrochemical use. Rosin consists of different resin acids that can undergo isomerisation at elevated temperatures and interchange its form, which, can be used as a rigid building block to manipulate their mechanical properties and crystallisation behaviours. Modified rosin epoxy binders have been recognised as materials with resistance to a wide variety of chemical conditions that can be used to fabricate a variety of reinforced constructions. Rosin has been employed in foam making in addition to composite material, depicting its ability as a crosslinker.

Abstract: Additive manufacturing has surged in popularity as a route to designing and preparing functional parts. Depending on the parts function, certain attributes such as high mechanical performances may be desired. We develop a route for improving the mechanical properties of polymer devices, fabricated through additive manufacturing by combining electrospinning and stereo-lithography into one automated process. This process utilises the impressive mechanical properties of carbon nanotubes by encapsulating and aligning them in electrospun fibres. Composite fibres will be incorporated into polymer resins prepared with stereo-lithography, thereby providing resins that benefit from the composite fibres properties, enhancing their overall mechanical properties.