<![CDATA[Fused Deposition Modeling (FDM) 3D printing technology is one of the additive manufacturing methods widely used due to its relatively low production costs, ease of processing, and compatibility with various thermoplastic materials such as Acrylonitrile Butadiene Styrene (ABS). However, FDM products generally exhibit high surface roughness due to layer formation during printing and display mechanical properties influenced by printing orientation. Acetone vapor smoothing (AVS) is commonly applied to improve the surface quality of ABS components, although excessive exposure may affect mechanical performance. This study aims to analyze the effect of acetone vapor smoothing duration and printing orientation on the mechanical properties and surface characteristics of ABS specimens produced using FDM. Specimens were printed with vertical and horizontal orientations and treated with acetone vapor smoothing for 0, 20, 40, and 60 minutes. Tensile testing was conducted according to ASTM D638 Type IV, while surface characteristics were evaluated based on layer line visibility and edge rounding. The results indicate that printing orientation has a significant influence on tensile performance, with horizontal specimens consistently exhibiting higher strength than vertical specimens due to better load distribution along the extrusion direction. A 20-minute acetone vapor smoothing treatment provided the most balanced condition by improving surface quality while maintaining mechanical properties. Longer exposure durations further reduced layer line visibility but caused greater edge rounding and a decline in tensile performance. These findings demonstrate that controlling both printing orientation and post-processing duration is essential to achieve a balance between surface quality and mechanical reliability of FDM-printed ABS components.]]>
