Recently, 3D printing has been actively studied. A representative material in this 3D printing technology is plastic, and PLA, an eco-friendly material, is widely used. FDM is widely used as a way to output these PLA materials. However, this method lacks mechanical properties compared to injection-molded products as it is a method of stacking materials by melting. Therefore, in this study, using an FDM-type 3D printer, a tensile test was performed after printing a tensile specimen with PLA filament with the layer angle and layer density as control factors. After that, changes in tensile properties according to the layer angle and density were compared and evaluated. As a result, to improve the tensile strength, the layer density had to be considered, and to improve the elastic modulus, both the layer angle and the layer density had to be considered.

A three-dimensional physical part can be fabricated from a three-dimensional digital model in a layer-wise manner via additive manufacturing (AM) technology, which is different from the conventional subtractive manufacturing technology. Numerous studies have been conducted to take advantage of the AM opportunities to penetrate bespoke custom product markets, functional engineering part markets, volatile low-volume markets, and spare part markets. Nevertheless, materials issues, machines issues, product issues, and qualification/certification issues still prevent the AM technology from being extensively adopted in industries. The present study briefly reviews the standard classification, technological structures, industrial applications, technological advances, and qualification/certification activities of the AM technology. The economics, productivity, quality, and reliability of the AM technology should be further improved to pass through the technology adoption lifecycle of innovation technology. The AM technology is continuously evolving through the introduction of PM materials, hybridization of AM and conventional manufacturing technologies, adoption of process diagnostics and control systems, and enhanced standardization of the whole lifecycle qualification and certification methodology.