Toolpath planning for multi-gantry additive manufacturing

Additive Manufacturing (AM), specifically Fused Filament Fabrication (FFF) is revolutionizing the production of many products. FFF is one of the most popular AM processes because it is inexpensive, requires little maintenance, and has high material utilization. Unfortunately, long cycle times are a significant drawback that prevents FFF from being more widely implemented, especially for large-scale components. In response to this, printers that employ multiple independent FFF printheads simultaneously working on the same part have been developed, and multi-gantry configurations are now commercially available; however, there is a dearth of formal research on multi-gantry path planning, and current practices do not maximize printhead utilization or as-built mechanical properties. This article proposes a novel methodology for generating collision-free toolpaths for multi-gantry printers that yields shorter print times and superior mechanical properties compared with the state of the art. In this, a metaheuristic approach is used to seek near-optimal segmentation and scheduling of each layer while a collision checking and resolution algorithm enforces kinematic constraints to ensure collision-free solutions. Simulation is used to show the resulting makespan reduction for various layers, and the proposed methodology is physically implemented and verified. Tensile testing on samples printed via the current and proposed methods confirm that the proposed methodology results in superior mechanical properties.