Abstract. Multiple-stream processes (MSP) can usually be found in a factory. MSP control chart is one of the tools used to control these processes. It is required that MSP control charts are selected appropriately based on streams characteristics, in order to minimize false decision on process status and irrelevant action on the process. This paper presents the guideline and a case study of selecting MSP control charts by considering the major factors, which are correlation among streams, number of streams, limitation to use one chart per stream, difference among streams average, and shift size of streams average to be detected.

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This paper aims to study the effect of using Oxidized White Liquor (OWL) on pulp brightness in peroxide bleaching. The proper setting of the concentration of hydrogen peroxide, the bleaching temperature, and the bleaching time was also studied. The Central Composite Design (CCD) was proposed to generate necessary experimental runs. Regression analysis was used to determine the relationship equation. Optimization helped determine that to obtain the targeted brightness of 83%, the ratio between the volume of OWL and sodium hydroxide should be 50:50. This ratio should be used with a concentration of hydrogen peroxide at 6.9 g/kg, a bleaching temperature of 90 oC and a bleaching time of 75 minutes.

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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.