Date on Master's Thesis/Doctoral Dissertation


Document Type

Master's Thesis

Degree Name



Industrial Engineering

Committee Chair

Biles, William E.


Six sigma (Quality control standard); Manufacturing processes--Quality control--Statistical methods


The objective of this thesis was to apply what was learned from Six Sigma while working for General Electric, towards real applications to improve processes. Two manufacturing problems were targeted. One of the issues dealt with variation, in an assembly process, which caused a large amount of missed opportunities. The other issue was based on defects caused by a reflector coating process that was creating haze and affecting lumens generated by the lamp. While analyzing the missed opportunity issue, a DMAIC approach was followed, measuring the collected data and analyzing the variation and mean of the processes by the use of box plots, Cause and Effect analysis, Pareto Diagrams, and Statistical analysis. After analyzing the data, three improvements on the machine were implemented. After analyzing the haze issue, a DOE was conducted to prove what factor was causing the haze. The missed opportunities were improved upon by implementing a preventative maintenance schedule and driving some "Quick Hit" projects for a total annualized savings of $140,000. The haze issue was proven, by a very simple 2X2 Design of Experiment, to be caused by the environment. By controlling the environmental conditions, the business was able to save $121,000 annualized.