การลดของเสียในกระบวนการพิมพ์พลาสติกโดยแนวทางซิกซ์ ซิกมา / วิทยา เจนจิวัฒนกุล = Defect reduction in plastic printing process by six sigma approach / Wittaya Jenjiwattanakul
This research applied the Six Sigma method for defect reduction in the printing process. The method is significantly based on statistical quality control concept. The Six Sigma approach has five steps in working process, which are Define Phase, Measurement Phase, Analysis Phase, Improvement Phase and Control Phase, respectively. This research followed the five steps according to five terms as follows : 1) Define Phase, defined the problems of the specified factory. Plastic printing process had the highest amount of defects of 41,759 Kg from the production of 357,486 Kg, or equivalent to 11.68%, in 2009. 2) Measurement Phase, started with the inspection of measurement system which had the result that met the acceptance criteria. Next, analyzed the problems by using fish bone diagram to get 20 factors. Then, screened the factors with Cause and Effect Matrix, and use FMEA technique to analyze until there were 3 factors left. 3) Analysis Phase, analyzed these 3 factors by using statistical method which verified that these factors contributed to defect occurrence. 4) Improvement Phase, used factorial experimental design to conduct experiment two times in order to get optimal value of each factor. 5) Control Phase, established guidelines to control and minimize the defect amount after an improvement. After improving the printing process, the results before and after the improvement were compared. The percentage of defect amount decreased from 11.68% to 1.53%, which means that the improvement process could reduce 86.90% of defects.