Process and productivity improvements through bottleneck reduction and design of experiments

Productivity improvements are critical to the long-term manufacturing success of a company. Much attention has recently focused on improving U.S. manufacturing productivity by using the lean production techniques demonstrated in Japan. A competing technique using the theory of constraints to optimize production has also gained some acceptance in U.S. industry. The objects of both techniques is to maximize production by the application of simple decision rules designed to minimize waste and focus resources where they can have the biggest impact. Additionally, design of experiments has been gaining wider currency as a means of improving the quality of manufacturing while simultaneously achieving the productivity improvements. This goal of this thesis was to evaluate the production operations of a large corporation engaged in the manufacture of a consumer durable product to search for ways to improve their productivity through the use of lean production, theory of constraints, and designed experimentation. One section of one plant was studied and implementation strategies designed and tested to study the application of these techniques in concert. This thesis examines the practical effects of implementing lean production and the theory of constraints as well as the use of designed experimentation in a production environment. It seeks to simplify an outline for deciding what changes to pursue and give practical experience in the problems of change implementation. It also discusses the use of design of experiments which was used primarily to identify process control variables and secondarily to optimize the process itself. This is of particular interest since it quickly identified the most important areas of the process to focus the plant's efforts to simultaneously improve both quality and productivity.