APPLICATION OF STATISTICAL PROCESS CONTROL CHARTS: A CASE STUDY IN DAIRY INDUSTRY

Abstract

Quality is a major part for entire industrial ecosystem when it comes to achieving, maintaining, and, improving the quality of products and services taking consideration of customer needs. Special causes responsible for controllable variations can be detected with the help of quality control charts-one of the quality management tools. Process can be improved by removing detected causes of variation bringing process under control. Statistical Process Control (SPC) Charts are quality control tools based on statistical principles which help to achieve quality of products by detecting special cause(s) of variation in the process involved. This paper incorporates a case study on application of Statistical Process Control (SPC) Charts tested at Sujal Dairy Pvt Ltd, Kathmandu, Nepal. Corresponding mean charts (Xbar charts) and range charts (R-Charts) represent data regarding quality variation for weight of milk pouch and SNF (Solid-Non-Fats) for both packaging machine 1 and machine 2. Results show that SNF variation for both machine and weight variation for machine 2 have been found to be under control whereas weight variation for machine 1 has been found to be out of control. Possible causes of variation have been grouped with the help of fishbone diagram and then compared with standard operating procedures for machine which led to detection of causes of variation. Finally, process has been better improved after removal of detected causes of variation bringing process under control.