Parametric optimisation for 3D printing β-tricalcium phosphate tissue engineering scaffolds using direct ink writing

The quest for optimal bone tissue engineering materials has led to extensive research on tricalcium phosphate (TCP) ceramics, specifically the β-TCP phase, due to its superior biocompatibility and bioresorbability. Ensuring the structural fidelity and accuracy in creating porous architecture is very crucial for β-TCP scaffolds. In this regard, this study explores the critical role of 3D printing parameters such as pressure, nozzle diameter, print speed, and solid loading in determining the dimensional accuracy of β-tricalcium phosphate (β-TCP) scaffolds fabricated through direct ink writing (DIW). Experiments were conducted on a custom-built DIW system based on a four-factor, three-level L₉ Taguchi design. The influence of these parameters on dimensional accuracy was evaluated using Analysis of Variance (ANOVA). Optimal process conditions to print β-TCP were revealed as 3 bar pressure, 0.6 mm nozzle diameter, 5 mm/s print speed, and 55 vol% solid loading, yielding minimal dimensional error. ANOVA results highlighted nozzle diameter and pressure as significant factors, followed by solid loading and print speed. Validation experiments under these optimal conditions achieved a dimensional error of just 1.52 %. Additionally, the scaffold printed under optimal conditions demonstrated a compressive strength of 2.64 MPa.