Exceptional mechanical performance by spatial printing with continuous fibre

For models giving complex 3D stress distribution under loads, typical planar-layer based fibre placement usually fails to provide sufficient reinforcement due to their orientations being constrained to planes. The effectiveness of fibre reinforcement could be maximized by using multi-axis additive manufacturing (MAAM) to better control the orientation of continuous fibres in 3D-printed composites.

They propose a computational approach to generate 3D fibre toolpaths that satisfy two reinforcement objectives: 

1) following the maximal stress directions in critical regions

2) connecting multiple load-bearing regions by continuous fibres

A hardware system with dual robotic arms is employed to conduct the physical MAAM tasks depositing polymer or fibre reinforced polymer composite materials by applying a force normal to the extrusion plane to aid consolidation. Details of the robot-assist manufacturing system (Hardware & Control) can be found at: https://github.com/zhangty019/Support_Generation_for_Curved_RoboFDM

When comparing to planar-layer based printing results in tension, up to 644% breaking forces and 240% stiffness are observed on shapes fabricated by their spatial printing method (with same amount of material usage). Material characterization of the breaking regions shown that the material failure has changed from the delamination between fibre and matrix material (up) into the fibre fracture (bottom) with fibre reinforcement printed with spatial toolpath. They demonstrate the versatility of their approach through various complex load cases which demonstrate their successful implementation of continuous fibre printing in various 3D models (please refer to technical paper for details).

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