There is significant work published in recent years about natural fibres polymeric composites. Most of the studies are about the characterization of natural fibres and their comparison with conventional composites regarding mechanical behaviour and application performance. There are dozens of types of natural fibres with different properties influencing their use, or not, in specific industrial applications. The natural origin of these materials causes, in general, a wide range of variations in properties depending mainly on the harvesting location and conditions, making it difficult to select the appropriate fibre for a specific application. In this paper, a comprehensive review about the properties of natural fibres used as composite materials reinforcement is presented, aiming to map where each type of fibre is positioned in several properties. Recent published work on emergent types of fibres is also reviewed. A bibliometric study regarding applications of natural fibres composites is presented. A prospective analysis about the future trends of natural fibres applications and the required developments to broaden their applications is also presented and discussed.

Additive manufacturing (AM) of polymer large parts is a technological research area with great growth potential if the main barriers to its implementation are successfully addressed. In this research, a review of large-format AM (LFAM) processes for polymers is presented, followed by market research concerning the identification of large-format polymer commercial printers. An overview was performed covering the current LFAM systems configurations and their control aspects. The design and modelling approaches related with the fabrication of polymer large parts by AM, and the materials currently being applied and under development, were described. Finally, a summary of LFAM applications with a focus in the Transportation, Academic, Construction and Energy sectors, was presented. The current main advances in the LFAM of polymers are linked with the possibility of producing large parts in a faster, cheaper, and reliable way. The market research analysis concerning results for all AM families involving polymer materials reveals that, currently, the material extrusion AM process family is potentially the most suitable to produce large parts, with a significant number of applications attesting its capability to produce such large-format components.

Purpose: – For decades multiple management philosophies directed toward lean production and mass were assumed as to respond to process inefficiencies and rampant consumerism, optimizing operation costs. However, new customization and flexible productions philosophies have been gaining ground in some industries, such as the agile manufacturing. From a literature review that addresses the history of this philosophy, it is clear that agile manufacturing is not fully comprehended, with very scarce information about practical cases. The paper aims to discuss these issues. Design/methodology/approach: – In this paper the authors describe an exploratory methodology approach, with three semi-structured case study interviews. The goal is to study which of agile manufacturing practices are being applied in the studied companies and what is the perceived effect that these have on operational performance. Since most of these companies develop highly customized products, the role of agility on new product development can have a huge impact on their operational performance. Findings: – Agile manufacturing is not yet a widespread philosophy of managing for the companies studied, being virtually unknown as a global concept. However, it was found that many of the practices of agile manufacturing are already implemented in these companies without association with this philosophy. It was also concluded, by the finding through respondents opinions, that agile practices contribute positively to the studied companies operating performance. Originality/value: – The novelty of this research derives from observation of agile manufacturing practices in SMEs. This research is useful to SMEs implementing agile manufacturing principles.

Purpose: The purpose of this paper is to investigate the effect of a sealing protective treatment on the water absorption and mechanical properties of acrylonitrile butadiene styrene (ABS)-printed parts by fused deposition modelling. Protective products include aqueous acetone solutions with different concentrations, polyurethane wood sealer and aqueous acrylic-based varnish. Design/methodology/approach: Open porosity was estimated by the absorption coefficient and the total amount of water retained, obtained from water absorption tests. Mechanical characterization was performed by compressive and tensile tests. Different specimens with different build directions and raster angles were used. Findings: The treatments with acetone solutions were not effective in reducing the porosity of ABS parts, as the amount of acetone that reduces effectively the porosity will also affect the sample dimensional stability. The polyurethane treatment was found to reduce the absorption coefficient, but the maximum water content and the open porosity remain almost unchanged in comparison with the ones obtained for untreated specimens. The treatment with an acrylic-based varnish was found to preserve the dimensional stability of the specimens, to reduce the open porosity and to maintain the compression and tension properties of the specimens in different build directions and raster angles. Originality/value: Surface modification for water tight applications of ABS 3D printing parts enables new designs where both sealing and the preservation of mechanical properties are important. As per the knowledge of the authors, the water absorption and the mechanical behaviour of ABS 3D printed parts, before and after treatment, were not previously investigated.