TY - JOUR
T1 - A new process capability index for non-normal distributions
AU - Chen, Jann Pygn
AU - Ding, Cherng G.
PY - 2001/12/1
Y1 - 2001/12/1
N2 - Many process capability indices have been proposed to measure process performance. In this paper, we first review Cp, Cpk, Cpm and Cpmk, and their generalizations, CNp, CNpk, CNpm and CNpmk, and then propose a new index Spmk for any underlying distribution, which takes into account process variability, departure of the process mean from the target value, and proportion of nonconformity. Proportion of nonconformity can be exactly reflected by Spmk. Its superiority over CNpmk, a recently developed index, also taking into account process variability and departure from the target value, is demonstrated with several non-normal processes. A method is proposed to estimate Spmk, with illustrations.
AB - Many process capability indices have been proposed to measure process performance. In this paper, we first review Cp, Cpk, Cpm and Cpmk, and their generalizations, CNp, CNpk, CNpm and CNpmk, and then propose a new index Spmk for any underlying distribution, which takes into account process variability, departure of the process mean from the target value, and proportion of nonconformity. Proportion of nonconformity can be exactly reflected by Spmk. Its superiority over CNpmk, a recently developed index, also taking into account process variability and departure from the target value, is demonstrated with several non-normal processes. A method is proposed to estimate Spmk, with illustrations.
KW - Measurement
KW - Process efficiency
UR - http://www.scopus.com/inward/record.url?scp=31644440459&partnerID=8YFLogxK
U2 - 10.1108/02656710110396076
DO - 10.1108/02656710110396076
M3 - Review article
AN - SCOPUS:31644440459
SN - 0265-671X
VL - 18
SP - 762
EP - 770
JO - International Journal of Quality and Reliability Management
JF - International Journal of Quality and Reliability Management
IS - 7
ER -