A Novel Method for Part Decomposition Based on Undercut Edges for Efficient Hybrid Rapid Prototyping
Layered Manufacturing allows physical prototypes of 3D parts to be built directly from their computer models, as a stack of 2D layers. This article proposes to decompose the model to be built into minimum number of layers and then build each layer separately by performing machining operations on a given sheet of metal, using a 3-axis CNC milling machine and adhering the layers, allowing large models to be built in parallel. The decomposition of the model is carried out in such a fashion that it decomposes all the inaccessible regions in the object such as under-cut concave edges. For a given build up direction, the undercut edges, which cause a part to be inaccessible by a tool, are extracted and eliminated in two decomposition steps ensuring that the number of layers are as least as possible, thus minimizing the build time.