A low-cost granular-medium hot quasi-isostatic pressing method for enhancing compressive properties of 3D printed structures

3D printed structures suffered weak bead-to-bead interfacial bonding due to the layer-by-layer manufacturing process. The hot isostatic pressing (HIP) method was effective in improving the micro-structures and enhancing the mechanical properties of 3D printed structures, but it was limited due to the high-cost device and process. Inspired by the HIP method, and aimed at improving the compressive properties of 3D printed thin-walled structures, this work proposed a low-cost granular-medium hot quasi-isostatic pressing (GMHQIP) method realized by the homemade equipment. The hot quasi-isostatic ambient pressure could be produced by pressing the granular medium in the high-temperature environment. The thin-walled structures treated by the GMHQIP method showed a more regular progressive deformation mode than non-treated structures. Compared to the non-treated structure, the specific energy absorption of thin-walled structures treated at 200 °C with 2 MPa for 8 h significantly increased by 170.4 % to the value of 4.95 J/g. The results indicated that the strength and toughness of 3D printed materials improved significantly after the GMHQIP treatment. The interfacial bonding of 3D printed structures was enhanced by using the GMHQIP method. This work offered a low-cost and efficient post-processing method for 3D printed structures to improve compressive properties.