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

Improving the Mechanical Properties of GlassFibre-Reinforced Laser-Sintered Parts Based on Degree of Crystallinity and Porosity Content Using a Warm Isostatic Pressing (WIP) Process

“…The WIP process was performed using a WIP machine consisting of a cylindrical chamber with a volume of 4400 cm 3 and upper limits for temperature and pressure of 350 • C and 100 bar, respectively. The LS-produced specimens were vacuum-packaged at room temperature using a polyimide film and sealant tape [9]. Afterwards, the vacuumpackaged specimens were placed inside the chamber.…”

“…Afterwards, the vacuumpackaged specimens were placed inside the chamber. Based on previous research by Park et al [9], the temperature during the WIP process was increased to 180 • C, after which a nitrogen gas at pressure of 90 bar was applied for one hour. The specimens were cooled in the chamber after the WIP process was finished.…”

“…However, after further analysis of the XCT data, as can be seen in Figure 8, some correlation can be observed regarding the residual fibre bundles and pores. Therefore, the influence of the porosity was investigated by applying the WIP process to the produced specimens to reduce porosity [9]. The WIP process was also performed in an effort to increase impregnation of the fibres as pressure is applied on the specimens at elevated temperatures.…”

“…Laser sintering (LS) is another AM technique which is often used to produce polymers and is regarded as the preferred polymer AM technology for producing structural components. This preference is attributed to its relatively low anisotropy in comparison to FFF and other extrusion technologies, superior surface quality, and final part properties akin to those achieved through conventional manufacturing techniques, thereby resulting in durable and robust components [9,10]. LS parts are extensively used across various industries, with 95% of these components manufactured from polyamide 12 (PA12), as the polymer proves itself to be well suited to the LS process [5,11].…”

“…To investigate the impact of porosity content on the LS specimens, the warm isostatic pressing (WIP) process was conducted. This method is well known for its ability to substantially reduce porosity content and enhance mechanical properties, primarily through an increase in the degree of crystallinity [1][2][3]9]. The effectiveness of the WIP process is investigated for both LS-produced specimens with and without fibres.…”