Rotation-Assisted Separation Model of Constrained-Surface Stereolithography

Among a variety of additive manufacturing technologies, constrained-surface image-projection-based stereolithography (SLA) technology has unique advantages in printing precision and commercial maturity. For the constrained-surface SLA process, separating the cured layer from the constrained surface is a crucial step that enables the fabrication of the current layer to accomplish. The separation process limits the accuracy of vertical printing and affects the reliability of fabricating. To reduce the separation force, current existing methods include coating nonsticky film, tilting the tank, sliding the tank, and vibrating the constrained glass. Compared with the above methods, the rotation-assisted separation method presented in this article has the advantages of simple structure and inexpensive equipment. The results of the simulation show that the pulling separation with rotating can reduce the separation force and shorten the separation time effectively. Besides, the timing of rotating is also crucial. A customized rotatable resin tank is used in the commercial liquid crystal display-based three-dimensional printer to reduce the separation force by breaking the vacuum environment between the cured layer and the fluorinated ethylene propylene film in advance. The analyzed results have demonstrated that this method can reduce the maximum separation force and the ultimate separation distance, and the reduction is related to the edge profile of the pattern.