Definition of Control Plan:
The intent of a process control plan is to control the product characteristics and the associated process variables to ensure capability (around the identified target or nominal) and stability of the product over time.
The process Failure Modes and Effects Analysis (FMEA) is a document to identify the risks associated with something potentially going wrong (creating a defect – out of specification) in the production of the product. The FMEA identifies what controls are placed in the production process to catch any defects at various stages on the processing.
Every completed Six Sigma project should have not only a control chart (if applicable), but a control plan. This ensures that the process doesn’t revert to the way it previously operated.