Unlike traditional gantry-based additive manufacturing (AM), robotic multi-axis AM processes offer the opportunity to continuously vary deposition path directions and tool orientations throughout the part. Since material can be deposited outside of the XY-plane, the multi-axis printing toolpath can be tailored such that the extruded composite material is aligned in full 3D with a part’s anticipated load path. In this way, the relatively weak layer interfaces are removed from the load paths, thus applying more of the load to the printed reinforcement and increasing the part’s mechanical properties.
This capability can be leveraged in conjunction with the geometric flexibility offered by AM, such that a part’s strength-to-weight ratio can be maximized through simultaneous topology and toolpath optimization (TTO). To enable the fabrication of structures within this context, the authors have created a novel TTO workflow that preferentially aligns and distributes composite materials in 3D via multi-axis AM. Specifically, this workflow employs a custom topology optimization algorithm to determine material distribution and orientation (in 3D) relative to the input load cases, aligns material depositions (i.e., the composite reinforcement) to those optimized directions, and orders the deposition paths for collision-free fabrication. In this presentation, printed parts resulting from the TTO workflow are compared to those made through conventional planar AM to demonstrate significant enhancement of structural efficiency.
- Describe the concept of multi-axis AM and define how it can be used to preferentially align anisotropy in a printed part.
- Describe how topology and toolpath can be simultaneously optimized to both lightweight a part and maximize its strength.
- Quantitively define the improvements in a part's structural efficiency gained through the TTO workflow, as compared to conventional planar AM.