Yulius Shan Romario’s research while affiliated with National Taipei University of Technology and other places

This study proposes the step-wise procedures involved in the development and fabrication of indigenous multi-resin 3D printer using vat photopolymerization process. The demand for simultaneous (i.e. single step) fabrication of multi-material intricate designs is exponentially increasing in the customization industries. The step-wise procedure involves the utilization of conceptual design approach to evaluate various sub-functions and their available solutions. Upon successfully identifying the sub-functions, their solutions, and the inter-dependency involved, three different types of multi-resin 3D printers are being be designed. Among the three proposed multi-resin 3D printer designs, the most optimized one is selected through the Verein Deutscher Ingenieure (VDI) 2225 guidelines. During the feasibility analysis as per the VDI 2225 guidelines, equal importance is given to the technical and economic aspects. Upon selection, the 3D printer is indigenously constructed using the locally available components and equipment. Moreover, the Taguchi method of level-3 is used to evaluate the best printing parameters for two different resins namely: DK-W (Dark-Water washable) and LT-W Light-Water washable). Furthermore, post-curing shrinkage analysis is carried out to examine the dimensional discrepancies. The excellent performance of the proposed printer was demonstrated by satisfactory printing of complex geometrical parts: Mobius ring and a ball inside a cage with acceptable accuracies.

The devastating effects of recent global events such as climate change and population explosion has demanded the need of natural resources beyond its availability. Apart from these devastating effects, the recent COVID-19 pandemic has made the world envisage the need for direct digital manufacturing to prevent upcoming supply-chain disruptions. In this study, a novel waste management technique is proposed in which the discarded oyster shell wastes are used as reinforcement in the additive manufacturing of clay components. To promote the concept of self-reliance, the clay-based material extrusion 3D printer is self-developed and the process parameters are optimized. The design for additive manufacturing principles is assessed to evaluate the threshold performance of the developed 3D printer using the oyster shell-reinforced clay material. Apart from that, the precision of the 3D printer is also evaluated using the 3D models to assess the efficacy of the 3D printer. The 3D printer can precisely print the minimum features of 8 mm, minimum width of 3 mm, overhanging angles of 32˚, and bridging length of 8 mm without any support requirement. The mechanical performance of the printed samples, treated with different sintering temperatures are also examined. The samples deliver excellent compressive and flexural strength of 429.57 MPa and 13.57 MPa, respectively at 1150˚C sintering temperature. Compared to the pure clay samples, the oyster shell reinforcement enhances the compressive and flexural strength of the composite by 26.5% and 34%, respectively. The composites also display enhanced tribological properties at ambient and elevated temperatures.

The sustainable replacement of automotive manufacturing sector is necessary to strengthen the sustainable development goals. Additive manufacturing (AM) equipped with topology optimization is known for fabricating components with reduced material and energy. In this study, the automotive flange fork is fabricated using laser-based powder bed fusion process (L-PBF). The topology optimization is carried out using the Ntopology software to generate two designs (i.e., design – 1 and design – 2) with the volume reductions of 26% and 46%, respectively. The compressive stresses exerted on the shaft and on the chassis by both the optimal designs of flange fork are examined using the finite element analysis (FEA). Considering the factor of safety of 2.5, design – 1 was found to be the optimal choice. The design is fabricated with the L-PBF using Inconel-718 material. Manufacturing quality analysis of the component shows the hatch distance of printed sample to be 18% lower than the set parameter. This difference was attributed to the non-homogenous size of the powder particles. Furthermore, the fabricated component is tested for its efficiency to withstand the torque of 300 Nm which is generated in most of the 4-wheeler automobiles. The torque analysis successfully demonstrated component’s ability without damage or cracks.