การลดของเสียในกระบวนการเขียนสัญญาณบนฮาร์ดดิสก์ไดร์ฟโดยใช้แนวคิดลีน ซิกซ์ ซิกมา / กันตา สุวรรณฤทธิ์ = Defect reduction of signal writing process in hard disk drive by lean six sigma / Kanta Suwannarit
This research was carried out in hard disk drive manufacturer. The preliminary survey indicated that the signal writing process of 2.5” Shasta product had high defects with 85,125 DPPM. The research aims to find the root causes of defect in signal writing process and reduce the ‘drive exceeded time limit’ defect which causes high fallout in the 2.5” Shasta product. Lean Six Sigma method is used as a process tools in this research. The methodology consists five phases which are define phase, measurement phase, analyze phase, improve phase and control phase. The result of the process is to determine KPIVs that significantly effect to drive exceeded time limit failure in signal writing process. Three KPIVs (screw driving speed, screw torque and helium pressure) have been used to perform and experiment. The result from Design of Experiment (DOE) is found that the appropriate screw driving speed is 1,200 rpm., screw torque is 4 in.lb. and helium pressure is 1.2 atm. Non-value added activity of the quality problem in signal writing process used Kanban system and ECRS to improve all the key process input to reduce drive exceeded time limit defect. Finally, the new process by standard practice and control in the acceptance level was developed as process control system. The data of drive exceeded time limit and overall defects on 2.5” Shasta product after improving the process show 39,346 DPPM and 45,420 DPPM improvement.
