Certified Six Sigma Black Belt Exam Lean Enterprise Concepts 4 — Questions and Answers
Question 1: Which of the following is NOT one of the five principles of lean thinking as defined by Womack and Jones?
- Identify value
- Map the value stream
- Eliminate defects at the source (Correct answer)
- Pursue perfection
Correct answer: Eliminate defects at the source
The five lean principles are: identify value, map the value stream, create flow, establish pull, and pursue perfection—defect elimination at source is a lean tool, not one of the five principles.
Question 2: A team performing a rapid improvement event (kaizen blitz) wants to reduce changeover time on a machine. Which lean tool is most directly applicable?
- Total productive maintenance (TPM)
- Single-minute exchange of die (SMED) (Correct answer)
- Value stream mapping
- Mistake-proofing (poka-yoke)
Correct answer: Single-minute exchange of die (SMED)
SMED is the lean methodology specifically designed to reduce setup and changeover time by converting internal setup steps to external steps.
Question 3: In SMED methodology, 'internal' setup activities are best described as:
- Tasks that can be done while the machine is still running
- Tasks that can only be performed while the machine is stopped (Correct answer)
- Administrative tasks completed in the office before changeover begins
- Tasks requiring two operators to complete safely
Correct answer: Tasks that can only be performed while the machine is stopped
Internal setup activities require the machine to be stopped, so converting them to external activities (done while running) is the primary SMED improvement strategy.
Question 4: The concept of 'one-piece flow' (single-piece flow) directly addresses which lean waste?
- Defects and rework
- Excess inventory and waiting between process steps (Correct answer)
- Over-processing and unnecessary motion
- Transportation and excess conveyance
Correct answer: Excess inventory and waiting between process steps
One-piece flow eliminates WIP inventory batches and the waiting associated with batch-and-queue processing, exposing quality problems immediately.
Question 5: A poka-yoke device that stops a process when an error is detected is classified as a:
- Warning poka-yoke
- Control (shutdown) poka-yoke (Correct answer)
- Sensing poka-yoke
- Attribute poka-yoke
Correct answer: Control (shutdown) poka-yoke
A control (or shutdown) poka-yoke automatically stops the process when a defect or error condition is detected, preventing defective output.
Question 6: In total productive maintenance (TPM), which pillar focuses specifically on preventing equipment deterioration through routine operator care activities?
- Planned maintenance
- Autonomous maintenance (Correct answer)
- Early equipment management
- Focused improvement (kobetsu kaizen)
Correct answer: Autonomous maintenance
Autonomous maintenance transfers routine tasks (cleaning, lubrication, inspection) to operators, enabling them to detect abnormalities early and prevent breakdowns.
Question 7: Overall equipment effectiveness (OEE) is calculated as:
- Availability × Performance × Quality (Correct answer)
- Uptime ÷ Total planned production time
- Throughput rate ÷ Takt time × Quality rate
- Mean time between failures ÷ Mean time to repair
Correct answer: Availability × Performance × Quality
OEE = Availability × Performance × Quality rate, providing a single metric that captures three major categories of equipment loss.
Certified Six Sigma Black Belt Exam Lean Enterprise Concepts 4
Which of the following is NOT one of the five principles of lean thinking as defined by Womack and Jones?