Binder jet printing (BJP) offers a cost-effective and highly efficient alternative to other additive manufacturing techniques. The engineering performance of printed parts is positively correlated with their densification. However, achieving high-density components for 316L stainless steel via BJP remains challenging, as numerous factors during both the printing and post-processing stages can influence the final density of the samples.
In this study, a printer and a proprietary binder developed by Concr3de were employed to fabricate samples using two sizes of 316L stainless steel powders (<18 µm and <25 µm). Following the standard workflow of printing, debinding, and sintering, various samples were produced by adjusting the printing and sintering parameters. Through characterization and comparative analysis, several key findings and conclusions were drawn.
The sintering process and density were examined, revealing that when the sintering curve included debinding at 450°C for 5 hours followed by sintering at 1400°C or 1410°C for another 5 hours, the sample density stabilized at approximately 94%, with peak values reaching around 98%. This provides a theoretical basis for future post-processing of BJP-manufactured 316L stainless steel samples in industrial applications.
Mechanical properties and shrinkage were also analyzed, showing that the mechanical properties (e.g., hardness) of the samples varied significantly under different sintering atmospheres. Additionally, the shrinkage rate perpendicular to the printing direction (N-direction) reached up to approximately 21% after sintering. Analysis of the printing process, combined with comparisons to other studies, suggests that the green parts in the N-direction exhibit a significant amount of compressible space, indicating that the current printing process leaves room for improvement in the densification of green parts.
Microstructural observations using SEM and OM revealed the presence of voids within the samples. These voids are suspected to be Type III pores during the sintering process.Binder jet printing (BJP) offers a cost-effective and highly efficient alternative to other additive manufacturing techniques. The engineering performance of printed parts is positively correlated with their densification. However, achieving high-density components for 316L stainless steel via BJP remains challenging, as numerous factors during both the printing and post-processing stages can influence the final density of the samples.
In this study, a printer and a proprietary binder developed by Concr3de were employed to fabricate samples using two sizes of 316L stainless steel powders (<18 µm and <25 µm). Following the standard workflow of printing, debinding, and sintering, various samples were produced by adjusting the printing and sintering parameters. Through characterization and comparative analysis, several key findings and conclusions were drawn.
The sintering process and density were examined, revealing that when the sintering curve included debinding at 450°C for 5 hours followed by sintering at 1400°C or 1410°C for another 5 hours, the sample density stabilized at approximately 94%, with peak values reaching around 98%. This provides a theoretical basis for future post-processing of BJP-manufactured 316L stainless steel samples in industrial applications.
Mechanical properties and shrinkage were also analyzed, showing that the mechanical properties (e.g., hardness) of the samples varied significantly under different sintering atmospheres. Additionally, the shrinkage rate perpendicular to the printing direction (N-direction) reached up to approximately 21% after sintering. Analysis of the printing process, combined with comparisons to other studies, suggests that the green parts in the N-direction exhibit a significant amount of compressible space, indicating that the current printing process leaves room for improvement in the densification of green parts.
Microstructural observations using SEM and OM revealed the presence of voids within the samples. These voids are suspected to be Type III pores during the sintering process.