Browsing by Author "Morris, Peter"

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    Additive manufacturing of heat-sensitive polymer melt using a pallet-fed material extrusion
    (Elsevier, 2018-10-28) Zhou, Zuoxin; Salaoru, Iulia; Morris, Peter; Gibbons, Gregory
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    Development of a direct feed fused deposition modelling technology for multi-material manufacturing
    (AIP publishing (American Institute of Physics), 2016) Zhou, Zuoxin; Salaoru, Iulia; Morris, Peter; Gibbons, Gregory
    Fused Deposition Modelling (FDM) is one of the most widely used Additive Manufacturing (AM) technologies to fabricate a three-dimensional (3D) object via melt processing of a thermoplastic filament. However, it is limited in the variety of materials that can be fed and mixed during the process. In this study, a concept of direct feed FDM technology was presented, which allowed co-feeding of multiple materials in any available form. Different materials were mixed at predetermined ratios and deposited together to form a 3D object with variable properties and functionalities that meet specific requirements. To demonstrate the capability of this AM system, heat-sensitive polyvinyl alcohol (PVOH) and its additives were processed. A geometry with various features was successfully manufactured with dimensions closely matching those of the design specification. The FDM processed PVOH showed insignificant thermal decomposition as it retained its original colour, flexibility, and water solubility. During the process, a fluorescent whitening agent was successfully incorporated into the polymer melt. Therefore, the printed sample exhibited a strong fluorescence effect from the UV-visible and fluorimeter results.
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    Inkjet printing of polyvinyl alcohol multilayers for additive manufacturing applications
    (Wiley, 2016-03-17) Salaoru, Iulia; Zhou, Zuoxin; Morris, Peter; Gibbons, Gregory
    Here we demonstrate that inkjet printing technology is capable of producing polyvinyl alcohol (PVOH) multilayer structures. PVOH water-based inks were formulated with the addition of additives such as humectant and pigments. The intrinsic properties of the inks, such as surface tension, rheological behavior, pH, wetting, and time stability were investigated. The ink's surface tension was in the range 30–40 mN/m. All formulated inks displayed a pseudoplastic (non-Newtonian shear thinning and thixotropic) behavior at low-shear rates and a Newtonian behavior at high-shear rates; were neutral solutions (pH7) and demonstrated a good time stability. A proprietary 3D inkjet printing system was utilized to print polymer multilayer structures. The morphology, surface profile, and the thickness uniformity of inkjet printed multilayers were evaluated by optical microscopy and FT-IR microscopy
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    Inkjet-printed polyvinyl alcohol multilayers
    (JOVE, 2017) Salaoru, Iulia; Gibbons, Gregory; Zhou, Zuoxin; Morris, Peter
    Inkjet printing is a modern method for polymer processing, and in this work, we demonstrate that this technology is capable of producing polyvinyl alcohol (PVOH) multilayer structures. A polyvinyl alcohol aqueous solution was formulated. The intrinsic properties of the ink, such as surface tension, viscosity, pH, and time stability, were investigated. The PVOH-based ink was a neutral solution (pH 6.7) with a surface tension of 39.3 mN/m and a viscosity of 7.5 cP. The ink displayed pseudoplastic (non-Newtonian shear thinning) behavior at low shear rates, and overall, it demonstrated good time stability. The wettability of the ink on different substrates was investigated, and glass was identified as the most suitable substrate in this particular case. A proprietary 3D inkjet printer was employed to manufacture polymer multilayer structures.The morphology, surface profile, and thickness uniformity of inkjet-printed multilayers were evaluated via optical microscopy.