Numerical Investigations On Sprue Configuration For Multi-Cavity Mould
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Date
2022-08-24
Authors
Badrul Hisham, Alya Nabilah
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Polypropylene is a thermoplastic addition polymer which is made up of several
propylene monomers. PP is a popular material used commercially as it is a versatile
material. Manufacturing of PP products through injection moulding and extrusion is
common. Injection moulding is a manufacturing technique that enables large-scale
production of items which includes injecting molten materials into a mould. The overall
goal of the study is to better understand how PP flows during injection moulding. The
first goal is to design a sprue configuration for multi-cavity mould. The second objective
is to conduct numerical investigations on the configuration to find the pressure in the
runners, and fluid velocity during injection. The final objective is to compare the
flowability between commercial grade PP and medical grade PP. The investigation is
done by conducting a numerical simulation, which is carried out using Ansys Fluent
2020 R1, while the sprues are meshed in Ansys Mechanical 2021 and modelled in
SolidWorks 2020. The simulation results show that higher injection pressure (49 MPa)
results in higher runner pressure (26466.66 KPa) as well as the fluid velocity (256.06
m/s) which gives lower fill time (0.91615 s) as opposed to lower injection pressure (45
MPa). On the other hand, higher injection temperature (220°C) results in runner
pressure (27973.42 KPa) but lower fluid velocity (233.34 m/s) which gives lower fill
time (0.90745 s) as opposed to lower injection temperature (180°C). This phenomenon
may occur due to shear thinning which influence the viscosity of a non-Newtonian fluid
where the viscosity decreases under shear strain Other than that, the medical grade PP
LB6331 generally has a higher flowability than the commercial grade PP TP6331 due
to exhibiting higher runner pressure (26888.08 KPa), higher fluid velocity (257.02 m/s),
and lower fill time (0.93265 s).