What does a high Cp or Cpk imply about a process's ability to meet specifications?

What does a high Cp or Cpk imply about a process's ability to meet specifications?

• A. The process is capable only if it is stable and centered near the target.
• B. The process is not capable under any circumstances.
• C. It guarantees zero defects in production.
• D. It reflects only the spread of data, not the process capability.

Answer: (A)

Cp and Cpk measure how well a process can meet specification limits given its variability. A high Cp means the process spread is small relative to the tolerance window, signaling potential to meet specifications, but this potential is meaningful only if the process is in statistical control (stable) and centered near the target. Cpk adds the reality of any offset from the target, showing the actual capability when the process may not be perfectly centered. Together, a high value indicates the process can meet specs if it’s stable and well centered around the target. It does not guarantee zero defects, and it isn’t just about the spread alone—it also reflects where the process is relative to the specification limits.

Cp and Cpk measure how well a process can meet specification limits given its variability. A high Cp means the process spread is small relative to the tolerance window, signaling potential to meet specifications, but this potential is meaningful only if the process is in statistical control (stable) and centered near the target. Cpk adds the reality of any offset from the target, showing the actual capability when the process may not be perfectly centered. Together, a high value indicates the process can meet specs if it’s stable and well centered around the target. It does not guarantee zero defects, and it isn’t just about the spread alone—it also reflects where the process is relative to the specification limits.