Concurrent consideration of product usability and functionality: Part I – development of integrated design guidelines

The market forces are pushing manufacturers to develop products which deliver the intended functions to users' satisfaction. Development of a successful product requires identification and incorporation of important product attributes. Since successful product designs require that a product be functional as well as usable, we aimed at integrating previously developed product usability and functionality design guidelines. These guidelines were developed from linking usability and functionality requirements to manufacturing variables. Part I of this three-part paper presents the procedural details for developing these integrated design guidelines. To integrate existing design guidelines a framework for a design process inclusive of several design criteria was established. An example case was used to integrate and generalise design guidelines. In Part II, the guidelines are validated by applying them to a consumer product that is directly used by consumers. In Part III, the guidelines are further applied to a sub-system of a complex consumer product.