Percorrer por autor "Pouzada, A.S."
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- Polymer flow dynamics in microimpressions: An experimental approachPublication . Zhiltsova, T.V.; Oliveira, M.S.A.; Ferreira, J.A.; J C Vasco; Pouzada, A.S.; Pontes, A.J.The melt flow dynamics of acrylonitrile-butadiene-styrene (ABS) and polypropylene (PP) in a variable thickness microimpression was assessed by monitoring cavity temperature and pressure as relevant process parameters. A micromoulding block with a variable thickness cavity was designed, manufactured and instrumented with pressure and temperature sensors, acting as monitoring devices as well as flow position markers during filling. A full factorial design of experiment (DOE) was carried to optimize the filling of the microimpression. This study with ABS and PP suggests that mould temperature is the more important parameter for the entire micromoulding thickness range under analysis. Nevertheless, the influence of the melt temperature and the injection speed were found to depend on the micromoulding thickness and the polymer type.
- Thermo-rheological behaviour of polymer melts in microinjection mouldingPublication . Vasco, Joel; Maia, J.M.; Pouzada, A.S.Microinjection has proven to be one of the most efficient replication methods for microcomponents and microsystems in various domains of microengineering. The use of available commercial microinjection equipment to evaluate the polymeric flow in microchannels would surely contribute to enhancing knowledge on polymeric flow at the microscale under industrial conditions. This approach is appropriate since rheological phenomena such as wall slip, surface tension, melt pressure drop and polymer flow length can be studied. These aspects are not fully dealt with in current commercial simulation software packages. In this study a micromould was designed to assess and characterize the flow in microchannels under realistic industrial conditions.