This research has two objectives: an economic model of flexible assembly systems that embodies accepted accounting practices, describes different part management methods, and allows different types of technology, different production batching strategies, and different product life cycles to be described; and assembly system design aids that help a designer to identify suitable assembly sequences, select assembly equipment (people, robots, fixed workheads, assembly cells) in the best mix, and create a system floor layout so that production volume, model mix, and economic return goals are met. The approach is to modify and extend two software programs, packaging and documenting them so that they can be distributed to industrial firms. An attempt will be made to generate an "expert system" for design purposes. Finally, various assemblies will be characterized as networks. These will be studied to determine their suitability for generating assembly sequences.