Most products are assemblies of components. The number of components can range from a few tens to a few millions. Assembly design involves the specification of component locations and orientations and the types of joints between them to achieve certain functional requirements. Current approaches to assembly modeling provide the designer the ability to specify high-level mating constraints between components which are then used to generate their locations and orientations. However, this provides little information about what types of joints have been created which have direct relevance to the functional performance of the product.
In this paper, we present a new methodology for computing component degrees of freedom from the specified high-level mating constraints. Two types of surface mating constraints are considered: fits and against. We show how multiple constraints of these two types constrain the component degrees of freedom. If the assembly being designed has a grounded component, the components’ degrees of freedom can be used to compute the joints that exist in the assembly. Eleven different types of constrained component degrees of freedom are defined ranging from unconstrained to completely constrained. An example is presented to illustrate some of the degrees of freedom.