3D Printing of Grinding and Milling Fractions of Rice Husk

Abstract

With the aim of sustainability approaches and production of designer 3D food packages, the present work examined the effect of printability of rice husk fractions of different size reduction methods: milled rice husk (MRH) and mixer ground rice husk (MGRH) with and without the addition of guar gum (GG). Extrusion test was performed for both the rice husk fractions and 3D printing process parameters were optimized for the ‘box’ shaped 3D model. Rheological behavior and physical characteristics were analyzed for all the material supplies. Printability of rice husk was only achieved in MRH + GG as the extrusion test revealed that MRH with GG was only found to be flowable out of the nozzle. Material supply namely MRH, MGRH, MGRH + GG showed shear-thinning behavior but found to be non-extrudable. Optimized conditions of printing were obtained at 2100 mm/min printing speed, 300 rpm motor speed with constant 4 bar pressure. Desired printing with stable layers was observed at a critical nozzle height of 0.2 mm and the flow rate of 0.678 ± 0.003 g/min. Thus, the work demonstrates the conversion of non-printable rice husk to the printable form by the addition of GG into the milled fraction of rice husk which can be further utilized in food packaging thereby reducing the dependency on non-degradable petroleum-based plastics.