Abstract:
This research aims to improve the process capability of the assembly process of hard disks of size 2.5 inches by reducing loss of write/read area on track zero, track maximum and the number of tracks per inch. This research follows the Six Sigma approach, which consists of five phases. Firstly in the define phase the problem, the objectives and the scope of the project were identified. In the measurement phase, the gage repeatability and reproducibility analysis and the process capability analysis of the three responses were performed. Then, the potential causes of variation were brainstormed and prioritized by using the Cause & Effect Matrix. Next in the analysis phase, the design of experiment (DOE) technique was used to determine significant causes to the mean and the standard deviation of the three responses. In the improvement phase, the response surface methodology was applied to define suitable factor levels that offer the mean of the responses closest to target. Finally In control phase, the control plan was set up to monitor responses and control the key process input variables. After the implementation of the new condition setting, the process capability indices of the three responses were higher than the acceptable standard value of 1.33. In addition, it was expected that the cost could be saved by 1,259,332 baht per month.