The $C_{pk}$ Target Range

A Process Capability Game

Your Goal:

You are a quality manager. Your job is to make your process *capable* of meeting customer demands.

Key Terms:

  • Specification Limits (LSL/USL): The blue "goalposts." This is what the *customer* demands. They are fixed.
  • Your Process (Bell Curve): This is what you *actually* produce. You can change it.
  • $C_{pk}$ Score: A grade for how well your process (the curve) fits *inside* the customer's limits (the goalposts).

The Rules:

- A $C_{pk}$ below 1.0 is failing. You are producing defects.
- A $C_{pk}$ above 1.0 is capable.
- A $C_{pk}$ of 2.0 is Six Sigma (nearly perfect).

Challenge 1: The "Wide" Process

$C_{pk}$ Score:

0.00

Goal: Your process is too wide (high variation). Reduce the variation to make $C_{pk}$ > 1.0!

100
10

All Challenges Complete!

Performance Review:

You've mastered process capability! You learned:

  • How to reduce **variation (spread)** to make a process capable.
  • How to **center** a process to improve its $C_{pk}$ score.
  • That a capable process ($C_{pk}$ > 1) must be both **narrow** and **centered**.