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Viscoelastic Properties of Polymer-Based Bionanocomposites Reinforced with Inorganic Fillers
Published in Senthil Muthu Kumar Thiagamani, Md Enamul Hoque, Senthilkumar Krishnasamy, Chandrasekar Muthukumar, Suchart Siengchin, Vibration and Damping Behavior of Biocomposites, 2022
Yeniova et al. (2016) investigated the viscoelastic properties of PLA/HNT nanocomposites with two types of plasticizer/toughening agent (i.e., polyethylene glycol and thermoplastic polyurethane) prepared using micro-injection molding. The E′, E″, and tan δ of the PLA/HNT nanocomposites was characterized using dynamic mechanical analyzer (testing parameters: tensile mode, heating rate: 1°C/minutes, and frequency = 1 Hz). From their study, it was found that the E′ was increased with the increasing loading of nanofiller. This is associated with the higher energy that is stored per cycle of oscillation, as well as the reinforcing effects of the HNT. The stiffening effects of the HNT are more prominent at temperatures below Tg (glass transition temperature). On the contrary, adding polyethylene glycol and thermoplastic polyurethane reduces the storage modulus of PLA/HNT nanocomposites.
Spark Erosion Machining
Published in Neelesh Kumar Jain, Kapil Gupta, Spark Erosion Machining, 2020
Originally, µ-SEM was developed to manufacture holes larger than 200 µm in diameter, in the metallic foils. It uses a tool electrode in the form of a tubular rod with dielectric fluid pumped through it to enhance the flushing within the working gap (Meeusen 2003). After the initial investigations, research interests in this field started fading till late 1980s, when Masuzawa et al. (1985) rediscovered this process by manufacturing very thin tool electrodes on-the-machine by using the WSEG process. These very thin electrodes were meant to be used as micro-pins to manufacture micro-holes. Further development in WSEG took place rather quickly, resulting in cylindrical tool electrodes less than 3 µm in diameter being produced. Tool electrode generation and re-generation is now considered a key enabling technology for stimulating the revival of µ-SEM, for it not only allows process scale down but also minimizes electrode wear. Hence, research interest in and applications of µ-SEM have been increasing continuously. It has thus become an effective and flexible process for the manufacture of complex 3D microstructures, cooling air channels in aerospace turbine blades, tooling inserts for micro-injection molding, micro-filters and micro-fluidic devices, micro-parts for watches, keyhole surgery, housings for micro-engines, and tooling inserts for the fabrication of micro-filters and micro-fluidics devices (Rees et al. 2007). Figure 1.11 illustrates micro-features manufactured by µ-SEM. Furthermore, μ-SEM can be combined with other processes to develop hybrid processes to expand the applications of μ-SEM (Ho et al. 2004).
Deep Proton Writing: A tool for rapid prototyping of polymer micro-opto-mechanical modules
Published in Paulo Jorge Bártolo, Artur Jorge Mateus, Fernando da Conceição Batista, Henrique Amorim Almeida, João Manuel Matias, Joel Correia Vasco, Jorge Brites Gaspar, Mário António Correia, Nuno Carpinteiro André, Nuno Fernandes Alves, Paulo Parente Novo, Pedro Gonçalves Martinho, Rui Adriano Carvalho, Virtual and Rapid Manufacturing, 2007
C. Debaes, J. Van Erps, M. Vervaeke, L. Desmet, H. Ottevaere, V. Gomez, S. Van Overmeire, P. Vynck, A. Hermanne, H. Thienpont
It is obvious that with a total cycle time of about half a day per component and the required cyclotron facilities, the DPW cannot be regarded as a mass fabrication technology as such. However, one of its assets is that it can be made compatible with low-cost replication techniques. Indeed, once the master component has been prototyped with DPW, a metal mould can be generated from the master by applying electroplating. After removal of the master, this metal mould can be used as a shim in final micro-injection molding or hot embossing step (Heckele and Schomburg 2004).
Precise WEDM of micro-textured mould for micro-injection molding of hydrophobic polymer surface
Published in Materials and Manufacturing Processes, 2019
Yanjun Lu, Fumin Chen, Xiaoyu Wu, Chaolan Zhou, Hang Zhao, Liejun Li, Yong Tang
Micro-injection molding was one of the most potential single-step replication methods to fabricate multi-scale hydrophobic polymer surfaces.[10] The micro-/nanostructure was first fabricated on the surface of a mold; then the micro-feature structure was transferred onto a polymer surface by single-step replication molding method. Due to the advantages such as simple forming process, stable product quality, high production efficiency, low cost, and easy mass production, micro-injection molding has been applied to wholesale produce plastic micro-parts in many fields, including health care, biology, sensor and actuator, micro-manufacturing and mechanical engineering, optical communication, and data storage.[11] Therefore, in this paper, micro-injection molding was employed to efficiently fabricate micro-textured structures on the surface of the polymer.