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Item type:Publication, Access status: without files , The technology of continuous fibre-reinforced polymers: a review on extrusion additive manufacturing methods(Springer, 2021-03-02); ; ; ; Additive manufacturing technologies have transitioned from the fabrication of prototypes to final product manufacturing with competitive mechanical performance. The use of materials with high strength to weight ratio, and more specifically continuous fibre-reinforced composites, has demonstrated potential when fabricated through fused filament fabrication (FFF). The development and evaluation of such technologies has attracted a lot of attention in recent years, from both academic researchers and from industry, and a plethora of different techniques for its achievement has been proposed. This review presents different methods of FFF for the fabrication of continuous fibre-reinforced composite components as described in both patent and scholarly research literature. Different print head designs and techniques for combining and depositing polymers reinforced with continuous fibre have been developed including pre-impregnation, the use of multiple nozzles for the separate deposition of the fibre and the matrix material, and in situ impregnation of the reinforcing fibre with the matrix material. This review identifies the challenges associated with each of these approaches such as achieving a successful fibre/matrix impregnation, cutting of the continuous fibres during processing, and the introduction of high-performance thermoplastic polymers as the matrix material.Publicationtype: Journal Article61 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Parametric study on tensile and flexural properties of ULTEM 1010 specimens fabricated via FDM(Emerald, 2021-02-01); ; ; ; Purpose: Fused deposition modelling (FDM) is increasingly being explored as a commercial fabrication method due to its ability to produce net or near-net shape parts directly from a computer-aided design model. Other benefits of technology compared to conventional manufacturing include lower cost for short runs, reduced product lead times and rapid product design. High-performance polymers such as polyetherimide, have the potential for FDM fabrication and their high-temperature capabilities provide the potential of expanding the applications of FDM parts in automotive and aerospace industries. However, their relatively high glass transition temperature (215 °C) causes challenges during manufacturing due to the requirement of high-temperature build chambers and controlled cooling rates. The purpose of this study is to investigate the mechanical properties of ULTEM 1010, an unfilled polyetherimide grade. Design/methodology/approach: In this research, mechanical properties were evaluated through tensile and flexural tests. Analysis of variance was used to determine the significance of process parameters to the mechanical properties of the specimens, their main effects and interactions. The fractured surfaces were analysed by scanning electron microscopy and optical microscopy and porosity was assessed by X-ray microcomputed tomography. Findings: A range of mean tensile and flexural strengths, 60–94 MPa and 62–151 MPa, respectively, were obtained highlighting the dependence of performance on process parameters and their interactions. The specimens were found to fracture in a brittle manner. The porosity of tensile samples was measured between 0.18% and 1.09% and that of flexural samples between 0.14% and 1.24% depending on the process parameters. The percentage porosity was found to not directly correlate with mechanical performance, rather the location of those pores in the sample. Originality/value: This analysis quantifies the significance of the effect of each of the examined process parameters has on the mechanical performance of FDM-fabricated specimens. Further, it provides a better understanding of the effect process parameters and their interactions have on the mechanical properties and porosity of FDM-fabricated polyetherimide specimens. Additionally, the fracture surface of the tested specimens is qualitatively assessed.Publicationtype: Journal Article30