In this study, the relationship between the color of the pigment added to the plastic resin and the size of the fractured part of the specimen was confirmed when processing ABS plastic tensile specimens using a sealed 3D printer. Through the test, it was confirmed that the fracture dimension existed in the range of 13.104 to 13.138 ㎜ and there was no significant difference in dimension according to the color of the additive, and the null hypothesis was adopted. In addition, it was confirmed that a significant difference occurred in the order of red, black, white, and green colors.
The amount of deflection that affect deflection caused by the load of steel board used to support concrete blocks were analyzed. By eliminating the central area of the cross section of board, it was possible to design a new board that reduces the weight of the board by about 50% while increasing the deflection by only about 10% for 5000N load. Since the deflection of the board is inversely proportional to the moment of inertia for area, it is most important to increase the cross-sectional height of the board to reduce the deflection, followed by the thickness of the upper and lower plates, and the thickness of the internal forming material played the smallest role. The other parts, the side supporting parts and reinforcing parts, were found to play a negligible role in preventing deflection. Applying the results of this study, we can predict the amount of board deflection and find the effective cross-sectional design of board without exceeding the deflection limit.
Research has been conducted on a wide variety of 3D printer circular fin heads. In this study, we proposed a sequence and method for a more efficient mesh study in the CFD model to calculate the Nusselt number of the circular fin head of an FDM 3D printer using the Taguchi method, sensitivity, and ANOVA. As a result, the CFD model to calculate the Nusselt number of the circular fin head of an FDM 3D printer has high sensitivity and contribution in the order of Base target mesh size, Prism layer number, and Prism layer thickness. We propose to increase work efficiency by performing mesh optimization in the order of factors with high sensitivity to level changes.
The purpose of this study intends to development of a lap scale 1-ton standard combustion chamber. The manufactured standard combustion chamber analyzes pilot combustion tests and emission standard data of MGO fuel oil. The actual capacity of the standard combustion chamber is about 900L, total weight of 265kg. As a result of the pilot combustion test, the O2 was about 8.01% and the CO2 was about 9.34%. In the case of NOx, it was about 33.50 ppm, and SOx (SO2) was about 0.76ppm. The combustion efficiency was about 72.41%, the exhaust gas temperature was 366.7℃, and the combustion chamber internal temperature was about 448.0℃.