An apparatus for enhancing the surface quality of the parts fabricated by additive manufacturing was developed in this study. The surface of the parts fabricated by additive manufacturing with different tilt angles, different curvatures, different aspect ratios, and low-pressure wax injection rapid tooling were treated by acetone vapor using the developed apparatus. The results found that the advantages of this apparatus include ease of operation, no waste chemicals, and low costs. The surface quality improvement rate for low-pressure wax injection mold is about 88.82%. The maximum aspect ratio for surface quality improvement is about 5.2. The surface quality improvement rate for parts with different curvatures is about 83-90%. In addition, the surface quality improvement rate for parts with different tilt angles is about 84-96%.