their light source over time. The customer was not aware of this normal bulb characteristic, but rather was under the assumption that as long as the bulb lit, a stable intensity would be produced. In addition to making the trend visible, we incorporated warning limits. This helped proactively determine when to replace the light source, therefore eliminating process time delays, costly scrap and rework. Through the implementation of this very simple Six Sigma tool, it helped the customer see the true root cause of their issue.