The Transition from Sampling to SPC
SourceModern quality control practice emphasizes the importance of process control in the creation of a quality product. When the process is in control it is possible to characterize the product forthcoming from the process, for the particular characteristic controlled, at the point in the process at which the control is instituted. When the process is out of control, the relationship between product and process is lost. It is then necessary to rely on acceptance sampling procedures to characterize the process. By combining the power of process control with the assurance of acceptance sampling, the process experimentation necessary for continual improvement can be undertaken with minimal risk to the consumer. An approach has been developed to transition from a process lacking control and/or capability to a controlled process with a Cpk value 1.33 indicating that the process is operating at an average level four sigma from the specification (s).