Lean Six Sigma Black Belt Certification Advanced Lean and Enterprise 3 — Questions and Answers
Question 1: In a lean enterprise, 'takt time' is calculated as:
- Total production time divided by number of workers
- Available production time divided by customer demand rate (Correct answer)
- Cycle time multiplied by number of process steps
- Shift length divided by planned downtime
Correct answer: Available production time divided by customer demand rate
Takt time = available production time ÷ customer demand, setting the required pace of production to meet demand without overproduction.
Question 2: Which of the following best describes 'mura' in the context of lean waste?
- Overburden placed on workers or equipment
- Unevenness or variability in production flow (Correct answer)
- Physical waste materials from manufacturing
- Defects causing rework
Correct answer: Unevenness or variability in production flow
Mura refers to unevenness or inconsistency in work flow, which leads to the other wastes (muda) and overburdening (muri).
Question 3: What is the role of a 'milk run' in lean supply chain management?
- A daily supervisor walkthrough of the shop floor
- A scheduled route for collecting small lots from multiple suppliers (Correct answer)
- A production smoothing technique for high-volume parts
- An audit process for incoming quality inspection
Correct answer: A scheduled route for collecting small lots from multiple suppliers
A milk run is a logistics method where a vehicle follows a fixed route to collect small, frequent shipments from multiple suppliers, reducing inventory and improving flow.
Question 4: In lean enterprise, which tool is used to balance workload evenly across operators to match takt time?
- SIPOC diagram
- Operator balance chart (yamazumi) (Correct answer)
- Spaghetti diagram
- FMEA
Correct answer: Operator balance chart (yamazumi)
An operator balance chart (yamazumi) visually compares each operator's cycle time against takt time to identify imbalances and redistribute work.
Question 5: What is 'heijunka' in lean production?
- Immediate line stoppage when a defect is detected
- Production leveling to smooth volume and mix over time (Correct answer)
- Error-proofing through device design
- Visual management of work-in-process
Correct answer: Production leveling to smooth volume and mix over time
Heijunka is production leveling, distributing production volume and product mix evenly over time to reduce mura (unevenness) and enable JIT supply.
Question 6: A Black Belt notices that a lean project's gains are eroding six months after completion. Which enterprise lean element was most likely missing?
- SIPOC mapping at project start
- Sustained standard work and layered auditing (Correct answer)
- Initial VSM current-state analysis
- Root cause analysis during the Analyze phase
Correct answer: Sustained standard work and layered auditing
Sustained standard work combined with layered process audits (LPA) is the lean control mechanism that prevents process regression after improvement.
Question 7: In a lean transformation, what does 'genchi genbutsu' require leaders to do?
- Delegate problem-solving entirely to frontline teams
- Go and observe the actual place where work happens (Correct answer)
- Conduct remote data analysis before visiting the floor
- Assign an A3 champion for each project
Correct answer: Go and observe the actual place where work happens
Genchi genbutsu (go and see) requires leaders to personally observe work at the gemba (actual workplace) to understand problems directly rather than relying solely on reports.
Lean Six Sigma Black Belt Certification Advanced Lean and Enterprise 3
In a lean enterprise, 'takt time' is calculated as: