P10: Numerical Simulations of Sintering Coupled with Heat Transfer and Application to Food 3D Printing

Pietro Rando, and Marco Ramaioli

University of Surrey, UK

3D printing is an additive manufacturing process in which materials are deposited layer-by-layer and bond (sinter) to form 3D objects that are customised in shape and/or composition. This process is investigated to produce personalised food, targeting the specific nutrition and texture requirements of each age group [1,2].

During sintering two solids bond together and reduce the total surface to minimize their interfacial energy. It is an important phenomenon in many manufacturing processes, including 3D printing, where the sintering of printed layers conditions strongly the mechanical properties of printed objects. Heat transfer can strongly affect the sintering dynamics [3]. At lower temperature the viscous dissipation increases, due to the higher viscosity, slowing down the sintering dynamics. Numerical simulations of sintering consider fluid inertia resulting in slower dynamics compared to the simplified analytical models. However, up to now, even the numerical simulations have neglected the strong viscosity gradients that can result from temperature gradients and have instead considered an uniform effective viscosity.

In this study, we present a novel and generic approach to simulate the sintering of 3D printed layers coupled with heat transfer. This approach can be applied to materials with a strong dependency of viscosity with temperature. The effect of the layer size, external and nozzle temperatures and heat transfer coefficient on the sintering and cooling dynamics is investigated. Lowering the layer thickness enhances both the sintering and cooling dynamics; whereas lower nozzle temperature slows down the sintering process due to the lower initial viscosity.

The results presented in this study can help optimising printing conditions or the formulation of the products to be printed. The novel simulation approach presented can be applied to a wide range of other sintering processes where viscosity gradients cannot be neglected.

Key dates

Registration deadline:

31 January 2022

Organised by the IOP Food Physics Group