Design of thermoformed plastic container using mould from three-dimensional printing for pear protective performance

Thermoforming is a widely used plastic packaging method due to its affordability, high protective performance, and ability to prevent mechanical damage to fruits during transportation. This study aimed to investigate the factors influencing the thermoforming packaging moulding process, evaluate the structural strength of thermoformed packaging, and assess the effectiveness of various shaped thermoformed containers in protecting pears. The prototype design was based on different geometric shapes and dimensions, divided into four relief geometries: cylindrical (M1), semi-circular (M2), geodesic dome (M3), square (M4), and commercial dome shapes. According to the mould thermoforming process, the mockups of each pattern were modelled using SolidWorks software and formed using a 3D printer. Polyvinyl chloride (PVC) plastic sheets were formed in a container mould with a thermoformed machine under the same parameter conditions of time, temperature, and pressure. The compression resistance of the thermoformed containers was tested. According to these findings, the compression force was higher in inferior thermoformed containers than in superior thermoformed containers. This is due to the relief size, geometry, and dimensions of the thermoformed containers. Then, thermoformed containers were employed to perform the dart drop impact test, with the pears dropped from heights of 20, 40, and 60 cm. The thermoformed container sample with a square shape (M4) had the lowest proportion of bruises (8.33%) on fruit. For container sample M4, the bruised area (BA) was assessed at drop heights of 20, 40, and 60 cm at 97.12, 140.75, and 206.02 square millimeters, respectively. Based on this finding, the bruise volume increased as the impact height increased. Additionally, a drop test was performed at a height of 90 cm using a thermoformed container with pears in a double-wall corrugated board for the BC flute. A higher total area of bruises on pears without thermoformed containers was observed in the evaluation of bruised damage. Therefore, this study concludes that the shape, size, and relief position of thermoformed containers reduce the damage caused by the compression strength and dropping height during transportation.