There is an expression that “no two snowflakes are alike.”  Similarly quality characteristics of parts produced from the same production process are not alike.

A simple production process, e.g., turning, can have variations in the machined diameter of a shaft because of play in the tooling or operators skill.  These variations lead to “quality risks,” i.e., if variations in the process are not controlled there is a risk of producing out-of-specification machined shafts. Continue reading →