Development of a design for service methodology

Product serviceability affects several areas such as warranty costs, life cycle costs, manufacturers profit and customer satisfaction. This dissertation describes the development of a methodology to determine the cost of servicing products at the conceptual stages of product design, thus enabling design teams to consider this important issue early in the development process. The impact of product structure on serviceability was addressed. Extensive studies of repair operations on automobiles, heavy duty commercial vehicles and computer peripherals were conducted and difficulties in carrying out repair tasks were classified. A generalized scheme was established to penalize repair operations based on the labor involved in their performance. Based on the classification scheme, time standard databases which can be used in the early design stages, were developed. This scheme and the associated databases were tested for several repair tasks and yielded satisfactory estimates. Two types of metrics were developed to evaluate service tasks in terms of service efficiency. The cost based metrics compare the customer\u27s perception of value added during the service to the cost of performing the repair. Criteria for an ideal design for service have been proposed. The time based metrics use these criteria to compare the repair time of the actual design with that of the ideal design for service. These efficiency measures were used to evaluate service tasks related to automobiles and computer peripherals. A computer model to represent mechanical assemblies called the disassembly diagram was developed. Based on the disassembly diagram, an algorithm was developed for efficient generation of optimum repair sequences. A LISP program using this algorithm, generated the optimum repair sequences of all the parts in assemblies consisting of up to 216 parts, in polynomial time. The other assemblies modeled included an automobile alternator. Input to the repair sequence generation procedure was achieved through a feature based scheme for describing the product structure