The desired shape of the protective packaging was firstly engineered to present a truncated cone geometry, conceptualized, and designed using CAD software. According to the length of the fibers used in the study, the mould geometry features a pattern of square-shaped apertures designed to execute the filtration function. The dimensions of the apertures were selected to ensure effective dewatering while preserving the shape of the filtered cellulose fibers.

The 3D-printing process was executed using a Bambu Lab 3D-printer, which has been validated for its precision, reliability and speed in similar applications. Utilizing a 0.4 mm nozzle, process was parameterized with an optimal layer height to ensure optimal resolution and mechanical integrity of the screen.

To provide dimensionally more stable samples, the wet pulp was blown into a heated aluminium mould and pressed with a heated counter-mould. Both, aluminium mould as well as counter-mould were prepared to fit with the 2 mm thick sample. The aluminium mould and counter mould for thermoforming were prepared by CNC mechanical processing.

As a reference pulp, commercial softwood and hardwood pulp in the ratio 40:60 was used. To this mixture, 20%, 30% and 40% of fibers obtained from Japanese knotweed and fibers obtained from Canadian goldenrod were added to prepare six different samples of pulp (besides reference). The fiber mixture was disintegrated and diluted to 0.9% concentration.

For the sample preparation, the 3D-printed mould which was fitted on a vacuum head was immersed into the fiber suspension and was sucked through the mould to form the fiber sample on the surface of the mould. After the formation, the sample was counter blown into the heated aluminium mould and manually pressed with a heated counter-mould. After this step the final drying was done by an oven with additional thermoforming.