Abstract:
The purpose of thesis was to apply the new theory Six sigma to solve problems faced in business. The critical to cost problems which found in Fiber Optics manufacturing was selected to study in this thesis. From studying historical data, this manufacturing process had high failure rate due to high optical loss of material. This caused increasing of manufacturing cost 5.01 USD per unit by average and made company profit reducing. The study aimed to decrease the failure rate of fiber optic material due to optical loss high from 26,700 defect parts per million to 7,810 defect part per million or less. The First step was analyzing and evaluating measurement system next was analyzing each process to find root cause of problem. The researcher found that unsuitable temperature and humidity in cool down process were key input variable factor (KPIV) and caused optical loss of material higher than specification. In the improvement step, the design of experiment technique was selected to find the suitable environment. After setting new temperature and humidity of cool down process following to statistical analysis result, the failure rate of fiber optic material due to optical loss high is reducing to 7,550 ppm. This can save manufacturing cost about 8,372 USD per year. In control phase, the guidance to control KPIV was introduced. Finally, optical loss of optical material was ascertained and optical manufacturing cost was also reduced.