SPC Implementation

Bill,
Implement slowly, and only on processes that are well understood. (through Six Sigma method) The successes I’ve had have been with charting  X’s, or process inputs such as temperature, pressure, etc. and not Y’s.
When an output is out of control, the operator has to know HOW to react. Otherwise, tweaking the process will occur creating worse conditions. This is a common downfall of SPC.