Product Design and Simulation for Metal Binder Jetting - An investigation of sintering deformation and design compensation in Simufact Additive

Examensarbete för masterexamen
Master's Thesis
Product development (MPPDE), MSc
Andersson , Simon
Dawson, Garrett
Metal Binder Jetting (MBJ) is an Additive Manufacturing (AM) method in which parts are built layer-by-layer using metal powder and a selectively deposited liquid bonding agent. MBJ can produce complex geometries with competitive physical properties. The as-printed part must undergo sintering to densify the component from ~50% to over 95% relative density and to achieve the desired physical properties. This densification corresponds to linear part shrinkage on the scale of 20% in addition to other deformations that may result from the high-temperature process. Shrinkage and deformation act as obstacles to creating parts with required geometrical tolerances when using MBJ. Simulations of the sintering stage of the process present one possible way to improve geometry when addressing and compensating for shrinkage and deformation. The Simufact Additive Binder Jet module, developed by Hexagon AB, uses a finite element analysis (FEA) simulation of the sintering process and material model to predict the change of the geometry and the deviation from the desired tolerances. Additionally, there is the option to create a compensated, pre-deformed geometry that should sinter to the desired geometry based on the simulation results. This work has focused on investigating the sensitivity of input parameters of the simulations and the accuracy of simulation predictions compared to experimentally printed and sintered parts. Investigation of simple 10mm cube geometries has shown that the Simufact simulations predict shrinkage on a similar scale to previous research but underestimate the shrinkage anisotropy in the build direction. When using the default material model, the pre-deformed geometry created by Simufact lead to an improvement in compliance with geometrical tolerances in 3 out of 5 tested geometries after sintering. An adjusted model applied to a complex geometry showed improved results from the default settings but with room for further improvement, indicating that adjusting simulation settings can improve simulation fidelity compared to real parts. Adjustments to the material model showed a more substantial influence on the results of simulation compared to adjustments in the sintering profile, with temperature notably showing little to no effect on predicted densification.
additive manufacturing , metal binder jetting , Simufact Additive , Sintering , shrinkage , deformation , simulation , design compensation
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