Design and surface enhancement of ABS parts manufactured by Arburg plastic freeforming (APF) using chemical vapor treatment

Abstract

Additive manufacturing (AM) has become a key technology for fabricating highly customized products without the need for specific tools. Despite the benefits, this technology has some limitations, such as a poor surface finish of the products. Chemical treatment methods have been proven effective for enhancement of surface finish. To this date, such treatments were applied to the objects manufactured by various AM methods, but there is no data available for the products manufactured by Arburg plastic freeforming (APF). The APF is a unique technique based on the deposition of tiny polymer droplets to build a final component directly from pellets. In this study, we investigate the effects of chemical treatment in hot acetone vapors on the surface roughness, (micro)mechanical properties, and optical and molecular changes of acrylonitrile butadiene styrene (ABS) samples produced by APF. The dynamics of the treatment process were studied as a function of exposure time to acetone vapors. The results showed that bulk mechanical properties were preserved, while significant changes occurred in the surface mechanics, specifically the indentation hardness. Along with the chemical treatment, the surface roughness exhibited nontrivial behavior but ultimately yielded a ∼ 90 % reduction after 35 s, texture homogenization with the simultaneous improvement in gloss, from 2.2 to 45 GU, and surface aesthetics. The surface finishing process was very fast and easily scalable, offering valuable information for the design of ABS products in industrial applications.