AbstractProcess capability indices are widely used inmanufacturing industry to measures process potential and performance inquantitative way. Process capability indices namely Cp and Cpk provide ameasurement to determine and predict the process’s performance. In this study,the mushroom bagging process data is acquired from C Mushroom CultivationFarm and process capability indices are calculated to determine the capabilityof the process. Lastly, some recommendations are provided based on the resultor data acquired to increase the capability of the process more effectively.Keywords.
Process Capability; Indices;Manufacturing Industry1 Introduction Process capability isestimation of performance level of the process in a long term. The process needs to be in control before it assessesits capability, else it will get incorrect estimates of process capability. Aprocess is a unique combination of machines, tools, methods and personnel engagedin providing a product or service. (Scoe, View, & Katikar, 2016) 8.Theoutput of a process can be product characteristic or process output parameter.Process capability indices provide a measurement to determine and predict theperformance of processes (Nagesh, 1800) 6 (P. C.
Lin, Y. T. Chung., 2007)9.
It can perform process capability graphically by drawing histograms andprobability plots. These graphics help to determine the distribution of thedata and whether the process is capable (C. C.
Wu, K. S. Chen, H. L. Kuo.
, 2003)2.It can also calculate capability indices, which are ratios of thespecification tolerance to the natural process variation (Federal, Offa, Federal, & Offa, 2013) 4. Process capability indices are a simple quantitativeway to measure the process capability.
It also can used to compare the capabilityof one process to another. Process capability indices measure the degree of theprocess produced output that meets customer’s specification and summarize processcapability information in a simple and easy way (Alan M. Polansky, S.N.U.A. Kirmani, 2003) 1 (K. S.
Chen, M. L. Huang, P. L.
Chang., 2006) 5. Cp and Cpk arequantitative expressions that personify the variability of its natural limitsrelative to the customer requirements.
There is some recommendations value forCp and Cpk to verify whether process capable or not. If Cp greater than 1 thenthe process is considered as capable (Silvano Bordignon, Michele Scagliarini, 2001)10, while Cpk is more widely used than Cp, since it takes into account themean and the standard deviation in its calculation (W. L. Pearn, K. S.
Chen., 1997) 11. The differencebetween Cp and Cpk is an indicator of how far the average of the process isfrom the target specification. When the average of the process approaches thetarget value, closer the gap between Cpk and Cp. When the average of thespecification is equal to the target value, then Cpk is equal to Cp.
Cpk cannever exceed Cp (Clara Novoa, Noel Artiles-Leon., 2008) 3 (N.F. Zhang, G.A. Stenback, D.M. Wardrop, 1990) 7.
In this study, the mushroombagging process data is acquired from C&C Mushroom Cultivation Farm andprocess capability indices are calculated to determine the capability of theprocess and show the application of process capability indices in manufacturingindustry.AcknowledgmentI had put lots of effortsin this technical paper. However apart from the efforts of me, it is impossibleto complete without the encouragement and guidelines from others.
Here is theopportunity for me to thanks to all of them. Firstly, I would like to show mygreatly appreciation to Dr. Shuhaida Ismail, my lecturer for Quality Improvement,who offered me invaluable assistance, support and guidance in all my way tocomplete this study. Besides, I would like to express my deepest gratitudetowards C&C Mushroom Cultivation Farm for their mushroom bagging weightdata and also provide necessary information regarding this study. Myappreciations same go to my family members and friends who are willing to helpme throughout this study with their abilities.