Using actual production runs of components to teach implementation of statistical process control techniques

As part of the Manufacturing and Plastics Engineering Technology (MET and PET) programs at Western Washington University, a different approach to teaching the implementation of statistical process control (SPC) methods has been undertaken. The MET students having already studied the fundamentals and applications of machining and computer numerical control (CNC) in required courses, produced small and medium batch runs of various machined metal parts in the machining processes laboratory. The PET students produced medium batch runs of injection moulded parts in the plastics processing laboratory. These parts were of various population sizes and had different quality characteristics and were used in teaching SPC techniques. Different quality characteristics which included both variables and attributes were monitored by the students during and after the manufacturing processes. The data collected was used to plot control charts for variables which included X bar, X, Range and Sigma charts. For attributes data, P, NP, C and U charts were plotted. An analysis of the charts was conducted to determine any special causes of variations using the application of run tests. The same data was used for conducting process capability analysis. With the use of actual produced parts and real data collection and interpretation, it was found that the students gained a better understanding of the fundamentals of SPC. The paper discusses the approach undertaken, its implementation, the results and some of the student reviews and evaluations collected after the process.