A product modeller for discrete components

Abstract

In designing a product, the product specifications are developed first, which conceptually constrains the geometry and functions of the product. Subsequently, its components are designed with the form in mind and achieve the functional requirements according to the specifications required. Conventional CAD systems are made for generating the geometric form of a part. This is meant to take the place of manual drafting. However, a system such as the one described above is incapable of capturing the non-geometric aspects of the designer's intent in a form that can be used for automatic process planning. The result is that tolerance, parts relationships, surface finish, etc. cannot be specified by the designer in the CAD environment unless some form of annotation is provided for. Product Modeller (ProMod) provides a concurrent product design environment for designers to assign the product specifications onto the parts' nominal geometry through a spatial relationships engine. With this information, the detailed design requirements, such as, tolerance and surface finish are generated by a dimension engine and tolerance propagation engine. Based on the functional requirements, the features of individual part are extracted through a form-function interpreter engine, then, they are mapped to the form and function database to establish manufacturing specifications such as machines and tools selection. Design evaluator evaluates the machinability and assemblability of features in accordance with the design rules, machine capability and geometric interference. Design advisor provides a way of incorporating modifications to improve the design. Design simulation unit formulates the problems which come from prototype design experiments and they are submitted to a design evaluator for further evaluation. When the iterative design procedures have been completed, the information, topology model, geometry model, dimension and tolerance model, form-function model, form-feature model, etc. are then created for generating the process planning.

Additional information

Notes on contributors

B. O. NNAJI

To whom correspondence should be addressed.