Additive manufacturing technologies such as Multi-Jet Fusion (MJF) enable the production of polymer parts with relatively isotropic mechanical properties; however, their surface condition often limits direct functional application. This study investigates the feasibility of selected surface treatments applied to PA12GB (glass bead-filled PA12) parts manufactured by MJF, with the aim of improving abrasion resistance and temperature-related performance through the modification of surface properties. Five surface treatments were evaluated: base coating (BC), acrylic coating (AC), chemical vapor smoothing (PostPro3D), glasscoat (epoxy-based SiO2 system), and a ceramic-filled 2K epoxy coating. Untreated samples served as a reference. Surface layer thickness, roughness (ISO 21920-2:2021), coefficient of friction (ASTM G99-23), and Shore D hardness (ASTM D2240-15R21) were measured. The results showed significant differences among treatments. Glasscoat and ceramic coatings formed the thickest and hardest layers (≈265 μm and ≈409 μm; Shore D ≈ 84) but exhibited substantially increased friction coefficients. Vapor smoothing and BC produced thinner layers with properties comparable to untreated samples. Acrylic coating reduced surface roughness while moderately increasing hardness. The findings demonstrate that surface treatments substantially alter the tribological and mechanical surface behavior of MJF-printed PA12GB parts. The suitability of a given treatment strongly depends on the intended functional requirements, particularly with respect to friction and surface hardness.
Fink et al. (Fri,) studied this question.