A Quality Control Analysis for Improvement of Product Using Cumulative Sum (CUSUM) and Exponentially Weighted Moving Average (EWMA)

This work presents a comparative study of the performance of the Cumulative Sum (CUSUM) as well as the Exponentially Weighted Moving Average (EWMA) control charts. The research is about quality improvement and systematic approach to reduction or elimination of waste, as well as rework and loose in production system. Starting from the data of a production process collected from the company, CUSUM and EWMA control charts were used to determine the (average run length (ARL) to detect a condition out-of-control. ARL found by each chart which was then compared. It was observed that the CUSUM control chart practically did not sign point’s out-of-control for the levels of variation between 1.0 standard deviation. For these variation levels the EWMA control charts was more efficient than CUSUM. Among the variables the weighted parameter of EWMA control chart with constant λ = 0.20 with their respective control limits UCL = 532.43 of net content, 4.01 of gas volume and 11.81 of brix level were the ones that detected larger numbers of altered positions. The ARL results show that the EWMA chart is slightly superior to the CUSUM chart, when the process is out-of-control. However, when the process is in-control, the converse is true. Conclusively the Coca-Cola Company should invest more on research and development to establish whether it is possible for the organization to produce carbonated drinks that would have no side effects to the consumers