A layerless additive manufacturing process based on CNC accumulation

Purpose - Most current additive manufacturing (AM) processes are layer based. By converting a three-dimensional model into two-dimensional layers, the process planning can be dramatically simplified. However, there are also drawbacks associated with such an approach such as inconsistent material properties and difficulty in embedding existing components. The purpose of this paper is to present a novel AM process that is non-layer based and demonstrate its unique capability. Design/methodology/approach - An AM process named computer numerically controlled (CNC) accumulation has been developed. In such a layerless AM process, a fiber optic-cable connected with an ultraviolet (UV) LED and related lens is served as an accumulation tool. The cable is then merged inside a tank that is filled with UV-curable liquid resin. By controlling the on/off state of the UV-LED and the multi-axis motion of the cable, a physical model can be built by selectively curing liquid resin into solid. Findings - It is found that the cured resin can be safely detached from the accumulation tool by applying a Teflon coating on the tip of the fiber-optic cable, and controlling an appropriate gap between the cable and the base. The experimental results verified the curing and attaching force models. Research limitations/implications - A proof-of-concept testbed has been developed based on a curing tool that has a diameter around 2 mm. The relatively large tool size limits the geometry resolution and part quality of the built parts. Originality/value - By incorporating multi-axis tool motion, the CNC accumulation process can be beneficial for applications such as plastic part repairing, addition of new design features, and building around inserts.