Adjusting Off - Centering Process for A Blow Molded Plastic Product by use of Winqsb Software


In most manufacturing processes, and in spite of statistical control, several process capability indices refer tonon conformance of the true mean ( c  ) from the target mean ( T  ), and the variation is also high. In thispaper, data have been analyzed and studied for a blow molded plastic product (Zahi Bottle) (ZB).WinQSB software was used to facilitate the statistical process control, and process capability analysis andsome of capability indices. The relationship between different process capability indices and the true mean ofthe process were represented, and then with the standard deviation ( ), of achievement of process capabilityvalue that can reduce the standard deviation value and improve production out of theoretical controllimitations and cost reduction.The study exhibits that when adjusting the center to the target value by adjusting the mold to the machine,the capability index ( p C ) enhanced by (14.56 %), capability index ( pk C ) is enhanced by (14.48 %),capability index ( pm C ) is enhanced by (12.5 %) and accuracy index ( a C ) is enhanced by (14.49 %). Thepercentage of the specification band used up by the process ( P ) is reduced by (12.8 %) and the degree ofvariation increases.