Numerical modeling of part sedimentation during volumetric additive manufacturing

Volumetric additive manufacturing has a number of advantages as compared to conventional additive manufacturing methods, but it can still suffer from premature sedimentation in which the part sinks down during the printing process - especially in the final seconds- affecting the method’s geometric fidelity, resolution, and limits its applicability only to high-viscosity resins. In this study, a numerical model has been developed to investigate the effect of different material properties and process parameters on the sedimentation of the printed part. After a qualitative validation of the model, the role of the resin viscosity in the sedimentation phenomenon is elucidated, and it is shown how a rise in the cross-section ratio of the printed geometry to the container can reduce the sedimentation, while an increase in the curing time and the container’s rotation velocity can escalate the sinking of the part. Furthermore, it is found that raising the final density and viscosity of the curing material at the end of the print will worsen and mitigate the sinking effect, respectively. Finally, the effect of the orientation of the printed part on the sedimentation ratio is explored. The model developed herein illuminates a new avenue for better understanding the physics taking place during volumetric additive manufacturing, which is essential to further improve the applicability of the technology.