Selectively polymerizing tung oil-based bio-resins by visible wavelength lasers

Bio-resin can be altered to experience chemical activation using a range of visible wavelength light sources, paving the way for an environment friendly resin curing mechanism with a potential application for additive manufacturing technology. Currently, additive manufacturing utilizes petroleum-based resins activated with an ultraviolet light source. In this experimental investigation, a tung oil-based bio-resin is used to examine how visible wavelength lasers cure resin only in localized areas either on surface or in subsurface and what parameters can be considered for process optimization. Additionally, experimental results are reported to observe the impact of color additives on the curing rate of the resin. Three different visible wavelength lasers are used for conducting the curing process—405, 450, and 532nm. The lasers run at their maximum power as well as equivalent energy density to observe their performances on the curing process. On the other hand, two types of initiators and two types of energy-absorbing pigment additives are mixed in combination to find out which combination improves the curing process the most. Trials are carried out on both base resin and additive-mixed resins to observe the effects of the additives. While both surface and subsurface curing of base resin is observed using 450nm wavelength laser exposure, subsurface curing of additive-mixed resin is observed using 405 and 532nm wavelength lasers. The tunability of these tung-oil based resins makes them attractive candidates for further research for numerous laser additive manufacturing processes.