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<abstract> <p>In recent years, recycling of plastics has opened several doors of advancements in the field of additive manufacturing (AM). The process of fused deposition modelling (FDM) has already been utilized for reprocessing waste plastics into filaments and finally printing them into useful products. Yet another concept of extrusion additive manufacturing (EAM) is gaining lots of attention. In this work, a screw assisted system based on EAM is designed and installed alongside a pre-existing FDM system. This system is referred to as the direct FDM (DFDM) system throughout this work. The DFDM system used operates with a 1.75 mm nozzle and has the ability of giving a high throughput. The focus of this work is to use this hybrid system (combination of FDM and DFDM systems) to print both virgin as well as recycled plastics. The scope of this work is to use one technology (either FDM or DFDM) at a time and to use both simultaneously for multi-material printing in future. After several trials of printing and setting up some printing parameters, the proposed system has been able to print with virgin as well as recycled PLA.</p> </abstract>

A successful attempt has been made to develop coir fibre composites reinforced with graphene, epoxy and carbon fibre. The carbon fibres were arranged in an intercalated manner, which is similar to the coir fibres. The percentage composition of graphene was varied as 1, 2, 4 and 6% by weight of the holding matrix. Suitable surface modifications were done by treating natural fibres by 5% NaOH and 0.3% KMnO4 for better adhesion of fibre and epoxy resin. Sonication and cetyl trimethyl ammonium bromide treatments were also done to achieve the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were made as per D638 American Society for Testing and Materials (ASTM) standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. Tensile testing was carried out to determine the mechanical properties of the composites. Two-way analysis of variance was used as a statistical tool to find the effect of parameters such as ‘Percentage composition of graphene’ and ‘Type of mould’ on the modulus of the composites. Fourier transform infrared spectroscopy was conducted to determine the interferential adhesion and homogeneous distribution of fibres in the composite matrix. At last, field emission scanning electron microscopy analyses were also done to the specimens before and after tensile testing to determine the morphology of different entities present in the composites.

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In this paper, tensile behaviour of the natural fiber composites such as the areca nut composites and the sunn hemp composites were determined. The fibers were arranged in different orientations such as the uniaxial, biaxial and the criss-cross arrangements. For both the types of fiber composites, specimens were made with and without the incorporation of E-glass fibers. Comparisons were done on the basis of fiber orientation, E-glass fibers incorporation and the type of natural fiber used. Initially, the fibers were treated with alkali, i.e. Sodium hydroxide (NaOH) in order to get better bonding at the fiber-matrix interface. The conventional hand lay-up technique followed by the soft compression molding technique was carried out for fabricating the composite specimens. It was inferred from the results that the tensile strength was more for uniaxial arrangement and the least for biaxial arrangement in case of both the fibers. Further, for both the fibers, E-glass fiber incorporation increased the tensile strength as compared to the non-incorporated E-glass fiber composites. Also, sunn hemp composites showed better tensile strength than areca nut composites. The research suggested that the areca nut and sunn hemp composites were assets to many potential applications that did not require very high load bearing capabilities. These examined composites can be considered as very reliable materials for fabrication of lightweight materials used in automobile industry, packaging materials, medical field, etc.