Dual-Wavelength Vat Photopolymerization with Dissolvable, Recyclable Support Structures

Vat photopolymerization (VP) is widely used for additive manufacturing due to its speed, precision, and material versatility. However, traditional support structures limit printable geometries, require manual post-processing, and produce non-recyclable waste. We introduce a wavelength-selective resin for VP that enables single-vat, multi-material printing with dissolvable supports. Exposure to one wavelength produces a rigid, dissolvable thermoplastic, while a second wavelength forms a crosslinked thermoset resistant to dissolution. This selective solubility vat photopolymerization (SSVP) process allows for the fabrication of complex objects with support structures removable using non-toxic solvents like mineral oil. Heat treatment further tailors crosslink density and solubility. Dissolved supports can be recycled into fresh resin and reprinted without mechanical property loss, eliminating waste and paving the way for fully automated, sustainable manufacturing workflows.