Title: A case study: applying Lean Six Sigma concepts to design a more efficient airfoil extrusion shimming process

Authors: Claiborne Hardeman, Paul L. Goethals

Addresses: G.E. Energy, Richmond, 23235, Virginia, USA. ' Department of Industrial Engineering, Clemson University, Clemson, 29634, South Carolina, USA

Abstract: When the objective of the manufacturer is to eliminate waste or create a more efficient process, innovative techniques are often sought for process improvement. The statistical tools used by Six Sigma practitioners are specifically designed for this purpose; they are frequently used to address problems across a wide number of production systems. Each manufacturing application, however, brings a unique array of potential causes and effects that must be considered to properly model process behaviour. This paper specifically examines a shimming process for a mechanically-driven screw press, whereby compressor airfoils (blades) are produced for a gas turbine. To enhance product quality and identify improvements in process performance, the five-phase approach to problem solving used in Six Sigma projects is applied. As a result of the changes implemented in this case study, the product defect level is reduced by as much as 94% and the Six Sigma rating is increased from 0.868 to 3.207.

Keywords: define measure analyse improve control; DMAIC; lean six sigma; critical-to-quality scorecard; failure mode and effects analysis; shimming process; airfoil extrusion; process design; screw press; compressor airfoils; compressor blades; gas turbines; product quality; product defects; process improvement.

DOI: 10.1504/IJSSCA.2011.039717

International Journal of Six Sigma and Competitive Advantage, 2011 Vol.6 No.3, pp.173 - 196

Published online: 15 Apr 2011 *

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