Printing Resolution and Depth-Of-Cure Study For Stereolithography 3D Printing Resins

Stereolithography (SLA) is a method of 3D printing of polymer resins using photoinitiated polymerization. Polymer thermosets with crosslinked networks are being formed in SLA. We have studied how the characteristics of SLA photocurable resins affect the 3D printing resolution and mechanical properties. Characteristics include the viscosity and the depth dependent UV polymerization kinetics. Real time FTIR with attenuated total reflectance sample stage was used to thoroughly study the UV penetration depth effects on the photopolymerization kinetics in terms of the rate of polymerization, on-set time for photopolymerization and monomer conversion. Three types of commercially available SLA resins are compared for the printing resolution and depth-of-cure characteristics. Additional tuning of depth-of-cure characteristics has been performed by mixing additional photoinitiator or inhibitor for the investigation of 3d printing resolution studies. Controlled post UV-curing is also performed to further manipulate their mechanical properties with an aim to elucidate how the network structure in SLA samples affect the stress-strain behavior of thermosets under tensile elongation. The layer curing process and morphology has been also investigated by DSC and microscopy techniques.