Improving the Quality of Asbestos Roofing at PT BBI using Six Sigma Methodology

Abstract

In Indonesia, many housing constructors are using asbestos as roofing which is partly supplied by PT BBI among many other suppliers. For PT BBI, the quality issue of asbestos roofing has been one of its key success factors in winning its customers loyalty. Therefore, PT BBI has set its strategic initiative to improve the quality of this product. Before the initiative was conducted, the sigma level was at 4.91 sigma with defect per million (DPMO) level at 200 units. By implementing six sigma methodology, the team found that this condition was mainly caused by side flat as its dominant defect type due to speeding up the curing time without simultaneously increasing its temperature. To solve this problem, the team has proposed that the company should increase its temperature up to to 350°C by DOE (Design of Experiment) if it needs to speed up the curing time from normally 5hours to 4hours. As the result, the quality figure was better with improved sigma level to 5.02 sigma and DPMO level at 180. This result might not be significant because there were still many other defect types found in the product that should be followed up by continuous improvement in the company.