REDUCING WAVY DEFECT ON HOT ROLLED COIL PRODUCT BY USING DMAIC APPROACH AT STEEL MANUFACTURER, BANTEN

Abstract

Quality of the finished product is one of the main concern from every company in order to satisfy the customers. PT. X well-known as steel manufacturer in Banten currently deals with a quality problem which is defect product. The company gain more losses due to defect product. DMAIC approach is used to reduce the number of defects and as a guidance for improvement process. It will create a way of identifying what caused products to fail to meet customer’s expectation and help to find out the root cause of defect problem. There are 8 categories of defect that contribute to repair issue in Hot Rolled Coil (HRC). From Pareto chart, wavy defect contribute to 44% of the total rework issue. Therefore, the research will focus on reducing the number of wavy defect. Based on fishbone diagram and five why analysis, the potential causes that contribute to the wavy defect is the heating temperature and sizing press temperature do not comply with the standard due to water seepage flows into the machine and cooling pipeline. This condition happened because the maintenance system is well-not managed. Maintenance interval time has been calculated in order to reach the desired reliability of furnace machine and to maintain the machine in a good condition. Preventive maintenance schedule has been made based on maintenance interval time. Checklist sheet, SOP, job evaluation and review are performed in order to maintaining and sustaining the improvement process. The result shows that the reliability of furnace machine after improvement is 81.39%. The total wavy defect per month is decreasing become 545.74 Ton and the sigma level increase 4% from 4.6 become 4.8.