Enhanced Properties of a Part Fabricated by Polymer-Based Powder Bed Fusion Using a Warm Isostatic Press

Parts fabricated by polymer powder-bed fusion (PBF) have numerous air gaps because of their deposition mechanism. The air gaps lead to a deterioration in the mechanical properties. To address this problem, a warm isostatic press (WIP) process was adopted, which could control the temperature and isostatic pressure in the chamber. When only the temperature was applied (called annealing), the tensile strength increased, but the elongation at break decreased in the specimens fabricated with the powders of polyimide 12 (PA12) because of the increase in the crystallinity without the reduction in air gaps. However, when temperature and pressure were applied together, the tensile strength increased compared to the tensile strengths measured from specimens treated with and without post-processing. The elongation at break compensates for the reduced value obtained by annealing. To identify the effect of the WIP process on the specimens from the PBF process, the mechanical properties were quantitatively investigated, and tightness and injection molding tests were carried out to qualitatively estimate the effect. From these tests, the effectiveness of the WIP process in the PBF process can be verified.