PKSC 4300: Stats 4 - process capability exam
What is a specification?: a defined requirement for a process or product property
What are good specification?: - its clearly understandable
a relevant requirement
is measurable with an agreed upon standard test method
has realistic and achievable limits
!!! based on statistics and normal distribution
What are bad specification?: - requirements exceed current state of art equipment
have imbalanced tolerances
How statistical tool with provide good specifications?: 1) Process capability index, C_p
2) C_pk
What is the purpose of the process capability index?: a tool for predicting the ability of a
process to meet a specification when the center of variation and center of specification are the same
How do you calculate a process capability index?: C_p = (USL - LSL)/(6*standard deviation)
USL=upper specification limit
LSL=lower specification limit
What does C_p > 1 mean?: Process is capable of matching specification
What is a specification?: a defined requirement for a process or product property
What are good specification?: - its clearly understandable
a relevant requirement
is measurable with an agreed upon standard test method
has realistic and achievable limits
!!! based on statistics and normal distribution
What are bad specification?: - requirements exceed current state of art equipment
have imbalanced tolerances
How statistical tool with provide good specifications?: 1) Process capability index, C_p
2) C_pk
What is the purpose of the process capability index?: a tool for predicting the ability of a
process to meet a specification when the center of variation and center of specification are the same
How do you calculate a process capability index?: C_p = (USL - LSL)/(6*standard deviation)
USL=upper specification limit
LSL=lower specification limit
What does C_p > 1 mean?: Process is capable of matching specification
