Continuous Process Improvement
Domain 2: Continuous Process Improvement
This domain tests your ability to improve a process using a factual, iterative method. Expect questions on PDCA, waste, standard work, 5S, kaizen, root cause, mistake proofing, SMED, TPM, OEE, and A3 thinking. The exam rewards problem clarity, direct observation, and countermeasures that change the process.
Core rules
- Start with the problem and current condition, not the solution.
- A standard is the baseline; without it, improvement cannot be sustained or measured.
- Pursue flow and remove waste: defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, excess processing.
- Go to the gemba and verify facts; do not rely on reports alone.
- Use root cause and mistake proofing where human error is predictable.
- PDCA: plan a small experiment, do it, check results, act by standardizing or adjusting.
- An A3 tells the story on one page: background, current and target condition, cause, countermeasures, plan, follow-up.
Worked example
A cell reports 12% defects. The team proposes "retrain all operators." A better response: stratify defects by type, time, shift, and station; observe the actual work; use 5 Whys. Suppose the torque driver drifts out of calibration after 500 cycles, and the check is visual only. The countermeasure is daily verification with a poka-yoke fixture that prevents use when out of range, plus standard work for calibration. Reasoning: training does not control drift, and the defect source is the process, not motivation.
Traps
- Jumping to training or "be more careful" without a process cause.
- Treating 5S as a cleaning campaign rather than a standard and visual control system.
- Calculating OEE incorrectly: availability × performance × quality, with planned time as the base.
- Confusing cycle time, lead time, and takt time.
- Closing an A3 at "implemented" without checking results and standardizing.