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.
