Tuning 3D-printing parameters to produce vertical ultra-hydrophobic PETG parts with low ice adhesion: A food industry case study

Abstract

The food industry is a dynamic component of the European economy. A wide variety of products and small batch are demanded in a market that is accustomed to frequenting changes in food packaging formats. Cheaper and lighter 3D-printed tools are replacing expensive metallic ones, producing previously impossible product geometries and processing fish and meat products more quickly and in more reliable ways. In addition to food contact, these printed parts are often required to have hydrophobic surfaces that facilitate cleaning and have low adhesion both foodstuffs and ice. In this study, the surface wettability of PolyEthylene Terephthalate Glycol (PETG) printed parts via fused filament fabrication is assessed. Specifically, several printing parameters (layer height, extrusion temperature, printing speed, acceleration, and flow) and their influence on the hydrophobicity of 3D printed parts with vertical orientation are analyzed. The experimental results indicated that the parameter with the strongest influence on the wettability of the XZ parts was flow: low-flow values generated ultra-hydrophobic surfaces, with contact angles higher than 120°. Acceleration had no influence at low flow values; however, for high flow values, low acceleration rates yielded higher contact angles. In addition, it was experimentally proven that the 3D-printed PETG parts with high-contact angle surfaces showed lower adhesion to ice than those with low contact-angle surfaces. The technology was applied to a case study of a 3D-printed hopper for the ice duct of an ice-cube machine.