Chemical vapor treatment of ABS parts built by FDM: Analysis of surface finish and mechanical strength

The present study investigates the simultaneous effect of part building orientation (along the X, Y, and Z axis) and raster angle (0°, 30°, 60°, and 90°) on surface roughness, tensile strength, flexural strength, consumption of model, support material, and building time of acrylonitrile butadiene styrene (ABS) test specimens fabricated by fused deposition modeling (FDM) process. Mechanical properties and surface roughness show a strong anisotropic behavior for the parts. For parts built with the X or Y orientations and 30° or 60° raster angle, pulling of fiber and a small amount of necking along with tearing are observed, which are responsible for higher strength. Post-built treatment of the parts with cold vapors of dimethyl ketone resulted in an immense improvement in surface finish. Exposing the parts in cold vapors turns the surfaces to a soft/mushy-like state due to the weakening of the secondary bonds, and the minor flow of polymer layers fills the cavity region between the adjacent layers and helps in improving the surface finish after the treatment.