An Additive Manufacturing Path Generation Method Based on CAD Models for Robot Manipulators
Abstract
Traditional extrusion based Additive Manufacturing (AM) is realized using a 3 Degreesof Freedom (DOF), translation only, 3D printer. Here, the printer must be larger thanthe printed part. One way of enabling AM in large-scale is to combine AM withrobotics. By using a 6 DOF robot manipulator to extrude a fast-curing material, theworkspace of the build would be greatly expanded and it would be possible to increasethe flexibility of the building process itself since the structure would no longer haveto be built from the bottom-up approach which is necessary for most existing formsof AM. This could possibly reduce the need for support structures to the point ofonly relying of anchoring and stabilizing. In this thesis, a method for generating apath for AM using robot manipulators that takes advantages of the robots DOF ispresented. The path is generated based on simple surfaces in CAD models. First, thesurface(s) is sampled and the samples are gathered in a point cloud. Then, a path isgenerated based on the point cloud using a path generation algorithm. Three differentpath generation algorithms was implemented and tested: greedy choice, weightedgreedy choice and Travelling Salesman Problem (TSP). Out of the three algorithms,the weighted greedy choice algorithm shows the most promise. With this algorithm,paths that enable printing along curved surfaces and reducing the need for supportstructures was generated. The method is effective, and by interfacing with FreeCAD, itis easy to review the generated paths through visual aids. It is, however, important tomention that the method only generates paths based on simple surfaces and is basedon the assumption of fast-curing material enabling mid-air printing.