Substrate and Build-Platform Adhesion in Vat Photopolymerisation: Wetting, Surface Treatment, Cure-State Coupling and Qualification

Weak build-platform adhesion can cause early detachment, layer slip or complete print failure, whereas excessive first-layer cure can increase dimensional distortion and make part removal difficult. Beyond the build plate, direct fabrication onto glass, silicon, ITO, metals and polymers requires a different evidence chain because successful printing is only the beginning of the interface life. Recent quantitative two-photon-polymerisation studies show that silanisation, plasma activation and polymeric interlayers can materially alter adhesion, and that geometry, solvent exposure and thermal history can change which treatment remains effective. DLP process studies likewise show that initial adhesion is coupled to exposure and separation loading. This review organises the evidence into six interacting variables: wetting and surface energy; chemical coupling; roughness and mechanical interlocking; interfacial cure state; residual stress and geometry; and competing separation loads. It proposes a minimum reporting and test architecture combining contact-angle/surface-energy characterisation, interface-specific mechanical testing, failure-location analysis and ageing. ISO 4624:2023, ISO 4587:2003 and ASTM D4541-22 are useful adjacent methods, but none is a dedicated VPP build-platform adhesion standard. 3Dresyns AA1, AA2 Bio, AA3 and AP1 are included only as manufacturer implementation examples; product positioning is not treated as independent proof of adhesion performance.