Assessing Surface Topographies of 3D‐Printed Polymer Tooling: Implications for Enhanced Injection Moulding Performance

Injection moulding (IM) is a precise manufacturing process capable of producing tight‐tolerance, functional plastic components with high‐quality surface finishes. However, the growing use of stereolithography (SLA) 3D printing for rapid, low‐cost mould fabrication presents a challenge, as the layer‐by‐layer process produces a stair‐step geometry that promotes a keying effect, leading to reduced surface quality, premature tool wear and poor part release during moulding. The study addresses the problem by examining the influence of print orientation on the stair‐step effect on SLA‐printed tooling by assessing how post‐processing (bead blasting, polishing) and CAD‐applied textures can improve surface integrity and tool longevity. A short production trial using polypropylene (PP) coupons measured surface roughness, contact angle and tool degradation. Post‐processed and CAD‐textured moulds effectively masked the stair‐step effect and improved lifespan, achieving Ra values consistent with IM standards (0.2–2.5 µm). In contrast, untreated moulds exhibited progressive wear and chipping before 20 cycles. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), scanning electron microscopy (SEM) and energy‐dispersive X‐ray (EDX) spectroscopy confirmed mould material transfer causing surface contamination, while CT scans revealed warpage and dimensional variation of up to 13% due to print orientation. These findings demonstrate that targeted surface modification strategies significantly enhance the performance of SLA‐printed moulds, providing a viable solution for short‐run IM applications.