Construction and Usage of Control Charts for Some Properties of Sugar Crystals
Statistical process control benefits organization by providing a systemic method for monitoring and evaluation of process variation. In this research application of statistical process control using variables control charts on the data from Al Gunaid Sugar Factory season (2015 – 2016) to test quality for three properties of sugar crystal namely purity%, colour(IU) and moisture%. The samples were selected at systemic randomness to cover all the season days. The periodic interval of sample was about 2 hours, the sample size is equal 10 and the subgroups are equal 15. Two variables control charts were constructed ( - charts and R-- charts) for the purity%, colour (IU) and moisture % of sugar crystals. Six random samples were taken and measured for the purity%, colour and moisture and plotted on the constructed charts. The average of purity% was 98.03% . The charts for purity of sugar crystal showed that, Three points were located below lower action limit and one point was located above upper action limits other points were located within the stable limits. This means that process was out of control The average of colour was 342.24 (IU). The -chart for colour of sugar showed that three points were located above upper action limit and three points were located above upper warning limits. This means that the process was out of control and therefore the cause for that should be searched for. The average of moisture was 0.0572 %. – chart for moisture showed that one point was located above upper warning limit, other points were located between the upper and lower warning limits this indicated the process was under control. The study recommended to construct control charts for other properties of sugar crystal such as Ash% , and Brix% .