Design For Assembly (DFA) is a method that is used in product design. With this method, the impact of influences of the choices that are made, can be seen in a early stage of the design. By connecting these effects (eg: cost, complexity) to characteristics of a design, it can be timely redesigned and adjusted as needed. Design For Assembly is part of a larger family of methods that are seen in the overall design methodology. This method is specifically aimed at optimizing designs for assembly, either manually or automatically.
The name DFA is the most widely used method and is connected to Geoff Boothroyd as developer of the method. Boothroyd developed this in 1977. There has been more a versions of this method, including one from the manufacturer of Hitachi. This was the so-called Assembly Evaluation Method (AEM). For each component was based on a single handling during assembly. Each additional action counts as a negative point. Optimization of the design for assembly was done by minimizing the number of points.
Boothroyd gives to any action a certain value (assembly time) and then looks for items such as quantity, symmetry, orientability and handling. In the analysis, values of the product are highly dependent on the ease with which it can be handled. For example, a symmetrical component is easier to orientate and a snap fit is faster to assemble then a screw connection. By distinguishing between different degrees of complexity in handling you not only can determine the exact assembly time but also the most expensive design decisions.