Professional Detailing1 min read

Ceramic Coating Quality Charts: Control Limits Are Not Specification Limits

Control limits describe process behaviour from data; specification limits define an acceptance requirement. They answer different questions.

Updated · NANOLAB Knowledge

Practical approach

Keep both sets of limits identified and use an appropriate statistical method for the process.

A stable filling process can still be centred outside the required fill specification. Conversely, one acceptable bottle does not establish process stability.

Decision limits

Do not replace the customer's specification with limits calculated from whatever the current process happens to produce.

Related guidance

Method reference: NIST: control and specification limits. References describe their stated methods or products; they do not certify NANOLAB products or establish compatibility with an unlisted surface.

Ask NANOLAB about the exact product and intended use. Use the current product documentation for formulation-specific instructions.