Certified Six Sigma Black Belt Exam Lean Enterprise Concepts 2 — Questions and Answers
Question 1: Which lean metric measures the percentage of total lead time that a product is actually being worked on (value-added time)?
- Process cycle efficiency (PCE) (Correct answer)
- Overall equipment effectiveness (OEE)
- First pass yield (FPY)
- Takt time ratio
Correct answer: Process cycle efficiency (PCE)
Process cycle efficiency = value-added time ÷ total lead time, and lean targets PCE above 25% for most processes.
Question 2: In a lean pull system, a 'signal' card used to authorize replenishment of a consumed batch from a supermarket is called a:
- Production kanban
- Withdrawal kanban (Correct answer)
- Emergency kanban
- Pitch kanban
Correct answer: Withdrawal kanban
A withdrawal (move) kanban authorizes moving a container of parts from the supermarket to the consuming process.
Question 3: A facility uses 5S. After the 'Set in Order' step, what is the primary purpose of the 'Shine' step?
- Eliminate unneeded items from the workspace
- Clean the area and use cleaning as inspection to detect abnormalities (Correct answer)
- Create visual standards for the organized layout
- Sustain improvements through audits and habits
Correct answer: Clean the area and use cleaning as inspection to detect abnormalities
Shine (Seiso) involves thorough cleaning and treats cleaning as an inspection opportunity to uncover equipment or process abnormalities.
Question 4: Which of the following best describes 'heijunka' in lean production?
- Eliminating all inventory from the production line
- Leveling the production schedule by mix and volume over time (Correct answer)
- Stopping the line when a defect is detected
- Building only to customer order with no supermarket inventory
Correct answer: Leveling the production schedule by mix and volume over time
Heijunka (production leveling) smooths the production schedule across a planning period to reduce variability in demand placed on upstream processes.
Question 5: An operator at a workstation stops production and calls for help the moment a defect is detected. This lean concept is known as:
- Poka-yoke
- Jidoka (Correct answer)
- Andon
- Gemba walk
Correct answer: Jidoka
Jidoka (autonomation) gives machines and operators the authority to stop production when an abnormality is detected, preventing defect propagation.
Question 6: Which waste category in the 8 wastes of lean (TIM WOODS) specifically refers to producing more than the next process or customer needs right now?
- Inventory
- Transportation
- Overproduction (Correct answer)
- Over-processing
Correct answer: Overproduction
Overproduction is considered the worst lean waste because it generates and hides all other wastes downstream.
Question 7: When creating a value stream map, the 'push' arrow symbol indicates that:
- Material flows based on a downstream pull signal
- Material is moved to the next process regardless of downstream need (Correct answer)
- Kanban cards control the flow between two processes
- Supermarket inventory has been established between processes
Correct answer: Material is moved to the next process regardless of downstream need
A push arrow on a VSM shows material being pushed forward based on schedules or forecasts rather than actual downstream demand.
Certified Six Sigma Black Belt Exam Lean Enterprise Concepts 2
Which lean metric measures the percentage of total lead time that a product is actually being worked on (value-added time)?