Multi-Nozzle Pneumatic Extrusion Based Additive Manufacturing System for Fabricating a Sandwich Structure with Soft and Hard Material

The additive manufacturing is an intelligent manufacturing technology that can quickly build a variety of complex objects with single or different functional materials. If additive manufacturing technology can be used to print mechanical structure with sensing or electronic feature, it will be able to break through the development bottleneck of a smart gripper and achieve the goal of rapid industrial development. In this study, a multi-nozzle pneumatic extrusion additive manufacturing system for printing soft and hard material structure was developed. The structure is made of a multi-material polymer which can be fabricated by using 3D printing machine. The liquid material is extruded through a tiny nozzle and then cured by a UV lighting source. The system architecture includes a CNC controller, which controls the nozzle through two stepping motors, both positive and negative pressures and curing light source are also manipulated with peripheral I/Os. A DA controller is also applied to flexibly control the air pressure for requirement of different injected flow speed. The program part is automatically executed with a numerical control software in CNC and PLC. Different pressures were set for extrusion nozzles with different materials. The G-code data was processed by Python Language and sent to the multi-nozzle pneumatic extrusion additive manufacturing system. This paper successfully printed a sandwich pad with soft and hard material structure, including double-layer material pad and three-layer material pad. A finer printing performance than a traditional FDM machine is achieved.