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Design of multi-scaffold fabrication system for various 3D scaffolds
사민우,김종영 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10
Three-dimensional (3D) porous scaffolds have been fabricated recently for tissue engineering applications through solid free-form fabrication (SFF) technologies. A multi-scaffold fabrication system for the fabrication of scaffolds, such as polymer, polymer/ceramic, ceramic,and nanofiber, was designed in this study. The various components, including a dispenser with a maximum pressure of 750 kPa, a thermostat with a maximum temperature of 250˚C, a high-voltage power supply with a maximum output of 60 kV, and a syringe pump with small flow control, play important roles in determining the process characteristics of scaffolds. The system can process applicable biomaterials with extremely high accuracy with a precision nozzle. Several 3D scaffolds, including PCL, PCL/PLGA/β-TCP, β-TCP, and PCL nanofibers, were fabricated. The morphology and pore size of fabricated scaffolds were observed through scanning electron microscopy. Results show that the scaffolds manufactured in this study can be effectively utilized as bone regeneration scaffolds.
FDM 3D 프린터를 이용한 바이오 세라믹 인공지지체 제작을위한 몰드 조건의 최적화
사민우,김종영 한국기계가공학회 2024 한국기계가공학회지 Vol.23 No.1
This study fabricated and evaluated 3D bioceramic scaffolds for bone tissue engineering using a mold generatedusing a fused deposition modeling (FDM) 3D printer. The line width of the mold creates pores in the scaffold. Producing a mold for the designed dimensions using a 3D printer does not yield the desired line dimensions andshapes. Therefore, in this study, experiments were conducted using the Taguchi method, and the optimalconditions were analyzed. The mold was optimized using process parameters such as the Stereo Lithography(STL), number of shells, and layer height. Bioceramic slurry with a mold was then sintered at 1150 °C toobtain a bioceramic scaffold. The compressive strength of the fabricated bioceramic scaffolds was evaluated bycalculating the stress strain curve. This bioceramic scaffold, fabricated through the mold method using FDM 3D –printing is a promising substrate for regenerating defective bone tissue.
반경방향 단조용 초경합금 맨드렐 및 해머 소재의 기계적특성 평가에 관한 시험 연구
사민우 한국기계가공학회 2024 한국기계가공학회지 Vol.23 No.1
This study aims to determine the applicability of mass production of products according to the radial forgingmethod. Mechanical properties and performance were compared and analyzed by exploring cemented carbidematerials that are currently recommended as mandrel and hammer materials. Two samples were prepared toexplore the suitability of cemented carbide materials for cold forging processes, which require wear and impactresistance, and to evaluate their mechanical properties. Tensile strength, bending strength, impact, and wear testswere selected as mechanical property tests. It was confirmed that a specimen made of a tungsten carbidematerial with a high Co content of 18% exhibited excellent impact resistance properties in the hammer material. However, in the wear evaluation, it was confirmed that the low Co content of 12% had less wear.
사민우,김종영 한국정밀공학회 2013 International Journal of Precision Engineering and Vol.14 No.4
Threedimensional (3D) scaffolds for tissue engineering have been described using a variety of molding and solid freeform fabrication (SFF) technologies. In this study, we developed a polymer deposition system for the fabrication of a scaffold similar to a bio-mimic tissue or organ. A 3D scaffold with a controllable pore size and high porosity can be implemented using this system. A precision 200 μm nozzle, thermostat with a maximum temperature of 250oC, and dispenser with a maximum pressure of 850 kPa play important roles in determining the deposition characteristics of molten polymer. Poly (ε-caprolactone) (PCL) and poly-lactic-co-glycolic acid (PLGA) were used to fabricate a biodegradable 3D scaffold. The dimensions of this scaffold were 25.0 × 10.0 × 4.0 mm. Scanning electron microscopy (SEM, Tescan VEGA Ⅱ LMU, Czech) was used to acquire images of the 3D scaffold. Biodegradable synthetic polymers were fabricated into 3D scaffolds for tissue engineering using various blending ratios: PCL, blended PCL(75)/PLGA(25),blended PCL(50)/PLGA(50), blended PCL(25)/PLGA(75), and PLGA. In this research, the compressive strength and modulus of the fabricated 3D scaffolds were measured from the stress-strain curves. Moreover, a CCK8 assay and the growth of MC3T3-E1 cells were evaluated at 37oC in a 5% CO2 incubator.