Part decomposition for die pattern machining

Casting patterns are usually made of weak materials that can be machined easily, and thus they are good candidates to be fabricated by hybrid RP machines that involve both deposition and 3-axis machining processes. However, the setup and machining time, and the number of required workpiece in the sequential processes are proportional to the number of the decomposed components. Hence, reducing the number of decomposed components at the pre-processing stage is an essential requirement to reduce the production time and the number of required workpiece. Existing hybrid RP machines, however, consider only one machining direction for all layers in decomposing a part into layers. This usually produces more layers than a method allowing different machining directions for each layer. This paper proposes a novel decomposition method for pattern fabrication that can reduce the number of components at the pre-processing stage. To this end, we propose a new three-step decomposition method, which comprises: (1) the determination of a set of machining directions, (2) the grouping of a part’s outer faces, and (3) the decomposition of a part’s inner region. The proposed approach in this paper could reduce the number of decomposed components, therefore would decrease the production time.