MICROSTRUCTURE AND SURFACE QUALITY ANALYSIS OF 17-4PH STAINLESS STEEL FILAMENT FABRICATED VIA VACUUM-ASSISTED FUSED DEPOSITION MODELING: PRE-DEBINDING & PRE-SINTERING

Abstract

In recent years, both polymer-based materials and stainless steel have been widely used in additive manufacturing, especially in the automotive and medical sectors. Among these materials, 17-4PH stainless steel filament, a polymer-based composite, has gained attention for aerospace and marine applications due to its excellent strength, corrosion resistance, and mechanical properties. However, with the growing use of fused deposition modeling (FDM) for metal fabrication, a deeper understanding of how the filament microstructure influences the final properties of printed components is needed. While previous research has emphasized microstructural integrity for successful debinding and sintering, limited attention has been given to the pre-processing stages. This study investigates the surface roughness of 17-4PH stainless steel filament fabricated via vacuum-assisted FDM before the debinding and sintering process. Samples measuring 10 mm x 10 mm x 5 mm were produced using an Ultimaker S5 at various vacuum pressures, layer heights, and printing speeds. Surface roughness was evaluated using a surface roughness tester, and surface morphology was analyzed using scanning electron microscopy (SEM). Each analysis shows that the sample printed using a vacuum has reduced surface roughness up to nearly 8.5 %. This improvement is attributed to vacuum-assisted printing, which reduces contamination, minimizing oxidation and porosity during the printing process. Besides that, outgassing characteristics and vacuum stability can also influence the printing. The printing parameters that are optimized can improve the mechanical properties of the products. These analyses are crucial, as they directly impact densification, porosity, and sintering behaviour, which in turn affect the mechanical properties of the final product.