Path Planning for Additive Friction Stir Deposition: Process-Specific Considerations

Conference Abstract: Additive friction stir deposition (AFSD) is an emerging solid state metal additive manufacturing technology, which can produce fully dense parts at a relatively high deposition rate in multiple alloy systems. Due to its advantages, AFSD can help address current limitations in the large scale castings and forgings supply chain. For broad implementation, however, automated path planning is required. This presentation describes path planning requirements that are specific to AFSD, including feed rate adjustments when overlaps conditions exist for adjacent tracks. In AFSD, parallel tracks are often deposited where the tool overlaps the previously deposited track, reprocessing that material into the current track. This ensures that the deposit is fully dense and that the neighboring tracks are fully bonded. However, feed rates must be adjusted to prevent both an overfed condition, which produces excess squeeze flash and increases forces, or an underfed condition, which leads to galling, voids, and a decrease in layer height. A method for calculating material and tool feed rates is presented that is based on the volume of material for a given track geometry (linear or curvilinear). The method is demonstrated for various geometries.