Process–Property Relationships and Mechanical Tunability of MEX-Fabricated Polycaprolactone for Bioresorbable Stent Materials

Material extrusion (MEX) has emerged as a promising method for fabricating bioresorbable stents (BRS); however, a systematic understanding of how process parameters regulate material-level compressive and flexural behaviour of polycaprolactone (PCL) under different loading modes remains limited. In this study, the effects of extrusion temperature (T _E ), material deposition speed (v _D ) and extrusion multiplier (M _E ) on the compressive and flexural responses of MEX-fabricated PCL were investigated using a response surface methodology framework. Distinct parameter sensitivities were observed between loading modes, with M _E identified as the dominant factor governing both strength and modulus through its control of volumetric material delivery and consolidation quality, while T _E and v _D acted as secondary modulators. Regression-based statistical models were developed to capture the nonlinear process–property relationships and were subsequently employed to define compression-focused, flexural-focused and multi-objective optimisation pathways, reflecting the clinically relevant trade-off between radial support and conformability in coronary stent design. Microstructural observations from cross-sectional SEM imaging provided mechanistic support for the parameter-dependent trends by revealing variations in material continuity, void distribution and defect suppression. By isolating material behaviour from geometric effects, this work establishes a tunable, geometry-independent mechanical window for MEX-fabricated PCL, offering a quantitative material baseline to support future design and optimisation of BRS architectures.