Integration of Lean Six Sigma and Ergonomics: A Proposed Model Combining Mura Waste and a RULA Tool to Examine Assembly Workstations

Abstract

Lean Six Sigma and Ergonomics have great importance in the implementation of continuous improvement. By combining Lean with Six Sigma, waste is eliminated and errors reduced by limiting activities that do not add value to processes, thus enhancing productivity levels. Increased productivity can also increase psychological and psychological stress on workers, however. Continuous improvement with the integration of Ergonomics principles in Lean Six Sigma enables productivity increases without compromising worker safety, generating healthy and comfortable work conditions within proper workstation layouts. Mura translates as unevenness or irregularity, and it occurs when there is an uneven process leading to inconsistencies. Mura can be applied to mechanical and human situations with regard to postural and biomechanical for desired tasks. Rapid Upper Limb Assessment (RULA) was used to assess postural movement associated with upper extremity Musculoskeletal Disorder tasks where the workers were standing or seated without moving about. The methodology of this research proposed a model based on the integration of Lean Six Sigma and Ergonomics by designing a diagnostic expert system combining tools focused on Mura time waste and a Rapid Upper Limb Assessment to identify the risk levels inherent in the postural movements of workers as part of the lean practice undertaken within the workstations in the assembly line.