An aperture system for a bottom-up stereolithography device including a reservoir having a lower opening, an aperture including a flexible membrane positioned within the reservoir and covering the lower opening, and a boundary seal positioned around a periphery of the flexible membrane, the boundary seal including one or more boundary seal components and immobilizing the periphery of the flexible membrane against the reservoir. The flexible membrane is formed of a material having a low affinity for a liquid resin used in the stereolithography device as well as cured photopolymer resin parts produced by the device. In addition, the flexible membrane is able to deform as the cured resin part is pulled away from the aperture, thus enabling lower energy mixed mode adhesive failure to occur at the interface between the cured resin and the aperture and reducing the chance of cohesive damage to the cured photopolymer part.