Despite significant industrial adoption of digital light processing (DLP) thermosetting resins, material waste reduction remains critical for sustainable manufacturing. This study demonstrates the technical feasibility of mechanically recycling cured DLP resin as particulate fillers (2.5–10 wt.%, 39–88 µm) in fresh epoxy photopolymer composites. The optimal formulation (5 wt.%, 59–64 μm, 60 min cure) achieved an ultimate tensile strength of 43.84 ± 2.1 MPa, versus 42.06 ± 1.8 MPa for virgin resin. Substantial confidence interval overlap (virgin: 40.26–43.86 MPa; recycled: 41.74–45.94 MPa) indicates no statistically significant difference ( n = 5). Equivalence testing (TOST, ±5% margin, p < 0.05) confirmed recycled composites perform equivalently to virgin resin, demonstrating successful recycling without property degradation. Microstructural analysis revealed optimal particle dispersion at 59–64 μm despite void clustering and agglomeration at extreme sizes. Recycled particles functioned as structural fillers with reinforcement efficiency dependent on particle size and dispersion quality. This proof‐of‐concept establishes the technical viability of mechanically recycling thermoset DLP resins, providing a foundation for circular‐economy approaches. Future work should evaluate long‐term stability and multiple recycling cycles.
Rooney et al. (2026) studied this question.