Profile offsetting for feature extraction and feature tool mapping in sheet metal

It is widely accepted that automatic process planning is the key solution to bridging the gap between design and manufacturing. In order to realize this, it is important that the CAD system should not only allow the designer to work in terms of features which relate to manufacturing operations but also be able to extract features and recognize them. Extraction of features internal to the contour of the sheet metal involves identifying groups that are connected to members within itself but not connected to any other group. However the same rationale cannot be adopted for features on the contour due to their lack of connectivity. This paper presents a new approach towards extracting contour features by generating the offset of the contour. It is important that once the features have been extracted and recognized, appropriate tools for creating the feature be identified. This paper proposes a tool mapping algorithm based on the medial axis transformation (MAT). Since stamping is assumed to be the method of manufacturing, feature-tool mapping involves identifying the punch which can stamp the feature.