Abstract:
The objective of this thesis is to improve the production process to increase productivity of D-dye type dye. This research applied the Six Sigma improvement approach. In the Define phase, it was found that in reverse osmosis process and spray drying process, the productivity of D-dye type was 19.97%, which was the lowest among all types. The goal of this thesis is to increase the productivity by 50%. In the Measure phase, it was found that the measuring machines are regularly calibrated. Thus, it was certain that the measuring machines give reliable measurements. In the Analyze phase, possible factors affecting productivity were listed out using by relation diagram and cause-and-effect diagram. Then, the cause-and-effect matrix was used to prioritize the causes. In the Improvement phase, onefactoratatime and Box-Behnken experiments were performed to test the significance of factors and find the optimal setting. The optimal setting was using one nozzle, with the diameter of 2.5 mm., amount of membrane washing water of 1712 kg., amount of process washing water of 324 kg. and the hot air temperature of 114 Co. In the Control phase, the confirmatory run was performed. The control plan was updated. Check sheet, work instruction control chart and graphs were created to control process factors, productivity and quality indicators to be within specification limits. After improvement, the productivity increased from 19.97% to 31.69%, equilavent to 58.66 % improvement.