A Robot-Centered Path-Planning Algorithm for Multidirectional Additive Manufacturing for WAAM Processes and Pure Object Manipulation

Abstract

Previous algorithms for slicing, path planning or trajectory planning of additive manufacturing cannot be used consistently for multidirectional additive manufacturing with pure object manipulation in wire-arc additive manufacturing. This work presents a novel path planning approach that directly takes robot kinematics into account and thus ensures the reachability of all critical path poses. In an additional step, the planned path segments are smoothed so that joint velocity limits are respected. It is shown that the implemented path planner generates executable robot paths and at the same time maintains the process quality (in this case, sufficient coverage of the slice area). While the introduced method enables the generation of reachable printing paths, the smoothing algorithm allows for the execution of the path with respect to the robot’s velocity limits and at the same time improves the slice coverage. Future experiments will show the realization of the real robot setup presented.

Development of a Multidirectional Wire Arc Additive Manufacturing (WAAM) Process with Pure Object Manipulation: Process Introduction and First Prototypes

“…For this application, pure OM is advantageous. For a pure OM holding the weld head including the periphery, the print component will perform large rotational movements [10].…”

“…The path planning algorithms related to this work were introduced by Schmitz et al [10]. For complex slices, the polygon is approximated, expanded, and then decomposed into multiple convex polygons for simplified planning.…”

“…These polygons can be filled with different infill strategies and different major orientations. To generate a connected path from the decomposition that is executable and optimized under welding and robotic requirements, a clustered hamilton path (CHP) is searched in a graph generated specifically for this use case [10]. The result of this calculation is mostly a very edged path, which cannot be executed by the robot due to the multidirectional properties of the process presented in this work [10].…”

“…In addition, collision risks are associated with eccentric wire feeding, since the attachment of the wire feeder to the moving and rotating torch can be twisted. By taking the abovementioned issues into consideration, in this research, pure object manipulation [10] is implemented for layer-by-layer deposition with multi degrees of freedom of movement.…”

Preliminary Process and Microstructure Examination of Flux-Cored Wire Arc Additive Manufactured 18Ni-12Co-4Mo-Ti Maraging Steel

“…By laying successive layers of appropriate dimensions, it is possible to shape the final form of the product. Unfortunately, a few starts and stops of the arc passing from one layer to another cause transient phenomena that slow down the printing process, which can be eliminated by using CTPP-Continuous Three-dimensional Path Planning [14] or Robot-Centered Path-Planning [15]. Attention is also paid to the detection of defects using High Dynamic Range Images [16].…”