7.A. INTRODUCTION

This chapter addresses the question of generating a good assembly sequence for a product. ^[1] The mathematics of assembly sequence analysis and the data models needed to support it take their form from the feature models of Chapter 3 and the constraint concepts of Chapter 4. Traditionally, choice of assembly sequence was the province of industrial or manufacturing engineers, and the choice was made after the product was designed, based on criteria that are relevant to factory operations. On this basis, the reader might expect to see this chapter grouped with others related to manufacture of assemblies. However, assembly sequence affects many aspects of product design and production, and is relevant to many life cycle issues of the product, so assembly sequence analysis should be part of early product design. In fact, assembly sequence choice focuses attention on so many strategic and tactical aspects of the product that this issue can serve as a natural launch pad for integrative product design.

Imagine a hypothetical product of six parts. We can build it many ways, among them bottom up, top down, or from three subassemblies of two parts each. What makes any of these ways better than the others?

There are construction reasons, such as space for tools that address fasteners or lubrication points. Similar considerations apply to ease of assembly, since some sequences may include some tricky part mates or awkward maneuvers whose...