Improving properties of a part fabricated by polymer-based powder bed fusion using a warm isostatic press (WIP) process

Abstract

Owing to the deposition mechanism, parts fabricated by polymer-based powder bed fusion (PBF) contain numerous porosities, which deteriorate mechanical properties. To address this problem, a warm isostatic press (WIP) process was adopted to control the temperature and isostatic pressure in the chamber. When only the temperature was applied (annealing), the tensile strength increased, but the elongation at break decreased in specimens fabricated with powders of polyamide 12 (PA12) because of the increase in crystallinity without a decrease in porosities. However, when temperature and pressure were simultaneously applied, the tensile strength increased compared with tensile strengths of 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 fabricated by the PBF process, mechanical properties were quantitatively investigated. Additionally, tightness and injection moulding tests were performed to qualitatively estimate the effect. These tests verified the effectiveness of the WIP process in the PBF process.

Keywords

• Additive manufacturing (AM)
• Polymer-based powder bed fusion (PBF)
• Warm isostatic press (WIP)
• Tightness
• Injection moulding