Hi, I’m Dolf Klomp and I’m a member of the Polymer Technology research group within the Department of Mechanical Engineering. My research topic entails the creation of a multi-material powder bed for 3D food printing. The research itself focuses on the prediction of powder flow behavior during the creation of a multi-material powder bed with a Discrete Element Method (DEM) simulation.
3D food printing is a very new field and is still expanding very rapidly. In this field, my research will help make the step towards multi-material food printing. After opening up the possibilitiy of being able to print multiple materials, the next step is to print anything that can be thought up by a culinary chef or food company.
For the simulation of powder flow, a DEM simulation is written that is specifically able to handle arbitrarily-shaped powders with a wide range of properties. The DEM simulation is based on 2D polygonal shapes that remain extendable towards 3D, keeping the required computational power to a minimum. The initial validation of the model is based on theory, while further validation will be based on experimental results.
In the creation of a multi-material powder bed, micro-dosing using an ultrasonic vibrating nozzle allows for the accurate dispersal of powder voxels. An experimental setup with several selected model powders was successfully used to validate this concept. The same experimental setup will be used to validate the DEM model.
THE UPS and DOWNS
It’s particularly tough to create a DEM model that can handle plastic-viscoelastic powder consisting of arbitrarily-shaped particles, as these can have multiple contact points. The main challenge is keeping this physically relevant while not relying on complete FEM models or known contact shapes. The challenge in the experimental validation, meanwhile, is in translating measurable bulk powder and material properties into microscopic material properties. This micro-macro transition is one of the main difficulties in DEM research. We have, however, been able to produce a DEM model that is capable of handling arbitrarily-shaped particles with different properties and is able to predict powder flow behavior through a miniaturized hopper.
Creating a foundation
This research ties in closely with that of Nicky Jonkers, in that my project simulates the initial steps in 3D food printing while his work simulates the outcome of this 3D food printing. Similar techniques can thus be used for analyzing the systems, and the acquired data can be used in both of our PhDs. Collaboration takes place on a personal, ad-hoc basis in which we keep each other abreast of the results of our research.