Influence of short carbon and glass fibers on the curing behavior and accuracy of photopolymers used in stereolithography

In this work, the influence of milled and chopped carbon and glass fibers on the curing behavior and accuracy of the acrylic-based photopolymer LOCTITE 3D 3860 was investigated. The analysis was performed using working curves and optical methods. A comparison between the two fiber types showed that using glass fibers leads to increased volume efficiency, which improved even more with increasing fiber weight fraction. The fiber length showed no significant influence. Superlogarithmic curing behavior under high exposure doses can be significantly reduced by using either fiber types. The increased volume efficiency compared to the pure photopolymer of glass fiber-filled photopolymers leads to a broadening in the xy-plane due to light scattering. In the case of carbon fibers, the effect is reduced, but with higher fiber weight fraction the achievable cure depth is strongly limited. The derivation of the exposure parameters for an accurate fabrication with fibers has been validated by a topology-optimized lightweight structure.