Recently, the demand for lightweight open-pore lattice structures with specific stiffness is increasing in many fields, such as the aeronautical, automotive, mechanical and bone tissue engineering sectors. For each concrete application, there is a need to predict its mechanical properties precisely and efficiently. There are several methods used to analyze the mechanical properties of lattice structures. Among them, the asymptotic expansion homogenization method is a more advantageous approach over the experimental, theoretical, and finite element methods, because it handles some of their limitations such as the time-consuming process, size effect, and the high amount of computational resources needed. Therefore, in this work, we use the asymptotic expansion homogenization method to perform a systematic parametric study to calculate the effective stiffness of different open-pore lattice structures. In addition, the designed models were fabricated using an SLA 3D printer, and the effective stiffness of the fabricated specimens was tested via UTM experiment to validate the numerical results computed by the asymptotic expansion homogenization method. Consequently, it was proved that this method is precise and effective for predicting the mechanical properties of lattice structures.

With advancements in the 3D printing technology, many industrial sectors are transitioning from traditional production methods, such as cutting processing, and casting, to utilizing 3D printers for manufacturing. For instance, in the automotive industry, the production of vehicle upright knuckle parts typically involves casting followed by machining processes, such as turning and milling, to achieve dimensional accuracy. However, this approach is associated with high processing costs and longer lead times. This study focuses on the production of vehicle upright knuckle parts using a selective laser melting (SLM)-type 3D printer, with SUS 630 as the material. To evaluate the feasibility of utilizing this method in industrial vehicles, this study conducts static and modal analyses, along with topology optimization. Additionally, experimental test drives are performed with the parts installed in KSAE BAJA vehicles, and modal frequency experiments are conducted. The objective of these analyses and experiments is to assess the performance, reliability, and applicability of utilizing SLM-based 3D printing for manufacturing vehicle upright knuckle parts by optimizing the design through topology optimization and evaluating the results through experiments and analysis.

Recently, competition in the manufacturing industry related to the preoccupation of new markets has drastically changed due to the increase in small quantity batch production products. Besides, business models utilizing 3D printing technology suitable for flexible manufacturing are gaining interest. As 3D printing technology is becoming more common, Design for Additive Manufacturing is also in the spotlight. However, the productivity of 3D printing technology is still insufficient in terms of mass production. In this study, the possibility of innovation in mass production process that combines 3D printing technology is presented through the case of innovation in manufacturing productivity of medium-speed engine cylinder head through the integration of sand 3D printing technology. It outlines how sand 3D printing technology is applied to cylinder head mass production processes, how the quality of cylinder head products can be improved compared to conventional pattern-based molding methods, and how productivity can be maximized by reducing process time and human error through hybrid production method with sand 3D printed integrated design cores. In conclusion, this paper presents the effectiveness of sand 3D printing technology which can secure product competitiveness by increasing the production capacity of mass production process, reducing production costs, improving quality, and reducing loss.

In this paper, a multi-material non-assemble 3-DOF Force-Sensor was proposed and developed to improve the efficiency in the manufacturing. The PLA-Filament was used to produce the frame-structure and the elastic-deformation, and the conductive-PLA-filament, to produce a transducer. A dual-nozzle 3D-Printer was applied to produce the monolithic-structuretype force-sensor with the multi-materials simultaneously in single-manufacturing-process. The sensor was designed in a tripod-structure to detect the 3-DOF force-components in an external-force and a mechanical-interpretation was conducted on the elastic-deformation, which acts as a load-cell. The output model of a Wheatstone-bridge circuit-based transducer serving as a strain-gauge was also produced. A calibration-testing device, comprising a rotating stage, which turns with 2- DOF (θ, ϕ), was also developed to apply force in every direction. By conducting the calibration test, the relations between the input and output were computed in as a matrix and the resolution of the sensor was determined through the evaluation of linearity and stability deviations.

The objective of this study is to verify the accuracy of performing surgery by developing and experimenting orthognathic surgical splints using 3D convergence technology. We performed the computation of the movement of the maxilla on the virtual simulation data for the surgery then designed the surgical splints using 3D CAD. We produced the designed splints and the test object and experimented on them using a 3D printer (accuracy ± 0.025 mm). The subjects were scanned using an optical scanner (accuracy ± 0.01 mm). We then compared and evaluated the simulated data and their accuracy. The evaluation results showed that the mean error range was within +0.313/-0.456 mm (average standard deviation 0.106), which was within the range of ±0.5 mm. These splints did not need for a reference point for external measurement to be set, neither did it need improving of the accuracy nor shortening the operation time. In addition, its advantage is that the amount of bone removal can be known accurately when the maxilla is repositioned.

Recent manufacturing methods for fabricating flexible devices have attracted a keen interest, with a strong demand by industrial manufactures. For thin film application on flexible devices, slot-die coating was found to be the most suitable method having excellent uniformity. Optimization of the reservoir of slot-die coater should be prioritized, since it is an important parameter affecting the uniformity of the final outcome of the coated layer. However, the numerous designs of reservoir makes prototyping difficult, and also results in high manufacturing cost. This study analyzed the velocity deviation of the slot-die coater outlet using CFD analysis, and shape optimization was performed by contour map. We introduce a facile and low-cost fabrication method for a slot-die coater, using polydimethylsiloxane materials and three-dimensional printing technique. The fabricated polymer slot-die coater was further evaluated by the leakage test of solution.