What is the difference between Lean, Six Sigma, and Theory of Constraints?
IW: Lean manufacturing focuses on the elimination of waste, while Six Sigma is a quality-based initiative, and Theory of Constraints is concerned with bottlenecks in processes. Lean manufacturing is an initiative focused on eliminating all waste in manufacturing processes. Principles of lean include zero waiting time, zero inventory, scheduling (internal customer pull instead of push system), batch to flow (cut batch sizes), line balancing and cutting actual process times. Six Sigma is a program that originated at Motorola where the objective is customer satisfaction through continuous improvement in quality. Six Sigma means products and processes will experience only 3.4 defects per million opportunities or 99.99966% good. The Theory of Constraints methodology of management, developed by Eliyahu M. Goldratt, proposes that in any complex system at any point in time, there is most often only one aspect of that system that is limiting its ability to achieve more of its goal. For that sys
