Papers by Keyword: Defective Reduction

Abstract: This research focused on defects reduction in spheroidal graphite iron casting process of a jackscrew manufacturer in which graphite nodularity was lower than a given specification (75%). This situation could lead to serious issues and accident to end-users. The Six Sigma approach of DMAIC was employed to identify and eliminate the problems. The result obtained after implementing the Six Sigma showed that the process capability was improved from-0.47 to 2.04, and the average per cent graphite nodularity was increased significantly from 61.49% to 86.43%.

Abstract: This research aims to demonstrate Six Sigma methodology to reduce defective rate. A case of glass-mold defective reduction in plastic lenses manufacturing was studied. After applying systematic DMAIC steps and statistical tools suggested by Six Sigma approach, it was observed that the defective rate due to scratched molds was decreased from 2,512 ppm to 826 ppm, and the sigma level was improved from 4.31 to 4.65. In addition, the improvement could save the production cost up to 75,000 USD annually.

Abstract: The objective of this study is to develop an efficient washing system to remove cutting oil from machining part surface. The proposed washing system consists of two processes: the dipping process and the modified automatic ultrasonic washing process. The automatic ultrasonic washing process is redesigned and developed to reduce operating cost and increase productivity from the previously developed machine. For this proposed system, experiments have been performed to determine the washing conditions that yield satisfactory proportion of defectives due to oil contamination. Under the suggested operating conditions, the proportion of defectives due to oil contamination is reduced from 12.8% to 1.78%, which leads to $16,800 defective cost reduction. The proposed washing system yields 42.9% increase in washing productivity. Furthermore, it as has more standard procedure than the current washing process.