The dimensional quality and mechanical properties of a fused filament fabrication (FFF)-printed 3D model are influenced by several process parameters. A forced-air cooling system that moves along with the print head was designed and installed on a commercial 3D FFF printer to control the cooling of the printed model. The quality of the printed polylactide (PLA) model, including the dimensions and mechanical properties, was investigated for different cooling air velocities. It was found that the cooling air velocity had different influences on the dimensional quality and mechanical strength of the printed model. More specifically, higher cooling speeds generated better geometric accuracy but lower mechanical strength. With the highest and lowest cooling air speeds of 5 m/s and 0 m/s, respectively, the tensile strengths of the printed models differed by 4-fold. In order to determine a suitable cooling air velocity setting for each specific printing material, a design model was proposed. The determined printing parameters were employed in the fabrication of a Rubik’s cube, as an example. The assembled cube demonstrated satisfactory performance both in the dimensional quality and in the mechanical function. Therefore, the cooling air velocity can be employed as an additional control parameter in 3D printing for a specified model.
Professor Chun-Ying Lee graduated from Department of Mechanical Engineering, National Taipei Institute of Technology, Taipei, Taiwan, in 1980, received M.S. degree in mechanical engineering from National Sun Yat-sen University, Kaohsiung, Taiwan, in 1985, and Ph. D. degree in engineering mechanics from Michigan State University, East Lansing, Michigan, U.S.A., in 1991. He is currently a Professor in the Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan. His current research interests include fiber-reinforced composites, smart materials, metamaterials, vibration control, tribocorrosion of electroplated coating, and supercritical carbon dioxide assisted plating process.