Effects of light exposure intensity and time on printing quality and compressive strength of -TCP scaffolds fabricated with digital light processing

Digital light processing (DLP), derived from stereolithography (SL), is a lithography-based additive manufacturing (AM) process that offers the ability to tailor scaffold shape, size, material, and biometrics of fabricated scaffolds to patient requirements. The additive manufacturing of tricalcium phosphate (TCP) bioceramic scaffolds via DLP is explored in the proceeding research paper. Particularly, the role of exposure intensity and exposure time on resultant scaffold quality and mechanical properties is studied. Increased exposure intensity results in an increased deviation from the designed lattice structure and thus an increase in compressive strength. Scaffolds produced with the highest exposure intensity, resulted in a 27.6 % error increase in mean beam diameter, resulting from an increased scattering effect, penetration depth, and over-curing of peripheral slurry. TCP scaffolds with an exposure time of 3.5 s and exposure intensity of 40 mW/cm2 possessed the highest print accuracy, resulting in the lowest average compressive strength - 82 MPa for the scaffolds of cube structure and 48 MPa for the ones of I-WP structure. Statement of significance: Digital light processing (DLP) is an effective additive manufacturing (AM) method applicable for bioceramics. This study focuses on the influence of light exposure intensity on scaffold quality and compressive strength. The increase of exposure intensity can improve the compressive strength with the sacrifice of structure accuracy. The conclusions of this study can provide insights into the relationship of DLP printing parameters and scaffolds quality.