Computer-aided blanking sequence design of extruded aluminum materials

Extruded aluminum alloys are presently used for building materials. We developed an expert system for blanking process planning for these three-dimensional materials using feature elimination. We consider that blanking adds features to a raw material and process planning eliminates features from a product. We attempted to implement a feature elimination procedure on computers. The shape model of the product consists of two parts, the basic material model and features. The basic material model represents the shape of a raw extruded material. It is a plain surface model made of polygonal faces. Feature models are also surface models. However, they describe a negative volume that represents the blanked parts of the product. The system chooses one face of the basic material model at the beginning of process planning, and collects the features’ faces on it. It searches a database, which we call the “processing case-base”, for each feature and finds the blanking procedure that can eliminate or create it. Repeating the above from the product to its raw material, the system develops process plans for blanking of the product.