An additive manufacturing device has a vessel for containing a polymerizable material, a build platform and a curing unit. The vessel has a flexible wall which is at least partially transparent to radiation at one or more wavelengths at which the material is polymerizable. The build platform is movable relative to the vessel to position a build surface thereof to face the flexible wall. The curing unit has a rigid component with a planar contact surface, the rigid component being at least partially transparent to radiation at the one or more curing wavelengths, and a radiation module positioned to emit radiation through the rigid component. The rigid component and the vessel are movable relative to each other. In a first position, the planar contact surface of the rigid component is in contact with the flexible wall, and in a second position, the rigid component is separated therefrom.