| Popis: |
Compared with traditional manufacturing methods, 3D printing is designed according to the needs of patients at a lower cost. Therefore, it has recently been developed vigorously in the application of medical equipment. The printing of biomedical materials with powder plastic (PEG-PCL) in the form of fused deposition modeling is one of the most recent key development projects. In this method, the plastic was heated and melted at the nozzle of the bucket and then printed. However, due to the existence of voids between the particles, the powder was melted, and the gas was coated in the melt. Due to the high viscosity of the melt, the air bubbles could not escape freely depending on the density difference, which led to a discontinuous plastic output during the printing process and, in turn, affected the appearance and material strength of the printed product. In this study, the Volume of Fluid method was used to simulate the rising process of bubbles in the molten liquid. By studying the internal flow of the liquid, the influence of the viscosity of different fluids on the rising of bubbles was discussed. In addition, the reliability of the simulation results was obtained through experimental verification. In the future, the rotating conical agitator should be used to generate forced convection inside the liquid to accelerate a rise in bubbles, and the influence of the conical agitator on the rise of bubbles at various speeds needs to be further studied. Finally, a suitable speed range was found for the most effective degassing effect. |
