This paper aims to demonstrate an effective approach for improving the process reliability within a flexible packaging manufacturing organisation. As the need for efficient industrial processes grows globally, industries tend to seek robust methodologies to chart their path to business excellence in terms of quality products and services. This research is focused on DMAIC methodology for investigating the root cause of slitting machines in terms of  low performance, and to proffer best solution to improve the process. Data collection plan which is based on lowest performing machines was obtained, followed by qualitative and quantitative process analysis to identify potential cause(s) for the machines' low process reliability. Statistical tools were used to validate the potential factors that are most probably critical for the machines performance improvement. The Six Sigma and DMAIC analysis indicate that actual operating slitting speed was below standard speed due to possibility of defective slit rolls, and presence of flags on jumbo rolls that accounted for 20% – 40 % of the gross downtime. Employee’s inability to capture process downtime were also identified as some of the vital critical factors affecting the performance of slitting machines. After implementing the Six Sigma-DMAIC solutions in the orgsnisation’s slitting processes, 21% improvement in the process reliability was achieved without compromising the quality of the slit rolls.This research can be used as a guiding reference for managers and engineers to undertake specific process improvement projects in flexible packaging companies. This study demonstrates how the application of Six Sigma-DMAIC can help manufacturing organisations to achieve improvements in their processes and thus contribute to their search for business excellence.

Keywords: Six Sigma, DMAIC, Process Reliability, Slitting Machines, Flexible Packaging