Statistical process control (SPS) is the application of statistical methods for monitoring and controlling processes. We use CPK to control our manufacturing process. A high CPK value indicates a stable process.
Our customers want us to achieve CPK 1.33. This simply means that 99.9937% of our items will be manufactured within set tolerances (provided the process is stable).
The photo shows one of our monitors in production. The list is real-time for the properties that currently have the lowest CPK value for manufactured items (a range between CPK 1.6 to 7.0)
With an outcome like this, we and our customers can be confident that our manufacturing process is stable.