Experimental investigation of hot chemical vapor smoothing parameters for enhanced surface quality control in SLS-fabricated PA12 parts

Purpose This study aims to enhance the postprocessing of selective laser sintering (SLS)–polyamide 12 (PA12) parts through hot chemical vapor smoothing (CVS) to achieve smoother surfaces and maintain dimensional accuracy suitable for biomedical and wearable assistive device applications. Design/methodology/approach A comprehensive experimental evaluation of the CVS process was performed using a trifluoroacetic acid (TFA)–dichloromethane (DCM) solvent system. A four-factor Face-Centered Central Composite Design (FC-CCD) was used to analyze the effects of TFA concentration, chamber temperature, exposure time and solvent volume on the surface roughness and dimensional accuracy of SLS-fabricated PA12 components. Findings The CVS results showed that exposure time and chamber temperature significantly influenced the surface finish of PA12 parts. Optimized parameters reduced Ra from 11.92 ± 0.34 to 3.45 ± 0.18 µm (71%) and Rz from 51.96 ± 1.42 to 12.57 ± 0.64 µm (76%), while minimizing dimensional deviation by 73%. Scanning electron microscopy revealed smoother, denser surfaces, and energy-dispersive X-ray confirmed that the chemical integrity of PA12 remained stable. Research limitations/implications This study is limited to a specific solvent–material combination for SLS-fabricated PA12 parts, potentially limiting its broader applicability. Future work should explore different solvent systems, more complex geometries and mechanical performance after smoothing. Originality/value This study provides a design of experiments–based optimization of chemical vapor smoothing parameters for SLS–PA12, revealing that solvent concentration, temperature and exposure time govern controlled surface quality.