CPM Plant Operations Management 3 — Questions and Answers
Question 1: In Total Productive Maintenance (TPM), autonomous maintenance is primarily the responsibility of whom?
- Dedicated maintenance technicians
- Plant engineers only
- Machine operators (Correct answer)
- Quality assurance personnel
Correct answer: Machine operators
Autonomous maintenance shifts routine inspection and minor upkeep tasks to machine operators to catch problems early.
Question 2: Which inventory model minimizes total holding and ordering costs by calculating an optimal order quantity?
- Just-in-Time (JIT) model
- Economic Order Quantity (EOQ) model (Correct answer)
- Vendor-Managed Inventory (VMI)
- Min-Max replenishment model
Correct answer: Economic Order Quantity (EOQ) model
The EOQ model balances ordering costs and holding costs to find the quantity that minimizes total inventory cost.
Question 3: A plant experiences a sudden spike in scrap rate. Which root-cause analysis tool creates a visual representation of potential causes organized by category?
- Pareto chart
- Control chart
- Ishikawa (fishbone) diagram (Correct answer)
- Scatter diagram
Correct answer: Ishikawa (fishbone) diagram
An Ishikawa diagram organizes potential causes into categories such as man, machine, method, material, and environment.
Question 4: What does the term 'changeover time' refer to in manufacturing operations?
- The time required to train a new operator
- The elapsed time between the last good part of one run and the first good part of the next (Correct answer)
- The scheduled downtime for preventive maintenance
- The lead time from order placement to delivery
Correct answer: The elapsed time between the last good part of one run and the first good part of the next
Changeover time (setup time) spans from the last conforming part of one production run to the first conforming part of the next.
Question 5: Which lean concept identifies and eliminates the eight types of waste (TIMWOODS) in manufacturing?
- Six Sigma DMAIC
- Value Stream Mapping analysis
- Muda elimination within the Toyota Production System (Correct answer)
- Theory of Constraints drum-buffer-rope
Correct answer: Muda elimination within the Toyota Production System
Muda (waste) elimination is a core principle of the Toyota Production System, targeting Transportation, Inventory, Motion, Waiting, Overproduction, Over-processing, Defects, and Skills.
Question 6: A plant manager wants to reduce work-in-process (WIP) inventory. Which lean tool directly controls the maximum amount of WIP allowed between process steps?
- Poka-yoke devices
- CONWIP or kanban limits (Correct answer)
- Statistical process control (SPC)
- Failure Mode and Effects Analysis (FMEA)
Correct answer: CONWIP or kanban limits
CONWIP and kanban systems cap WIP by limiting the number of work orders or cards in circulation between stations.
Question 7: When calculating labor efficiency variance, which comparison is made?
- Actual hours worked vs. budgeted hours at standard rate
- Standard hours allowed for actual output vs. actual hours worked, multiplied by standard rate (Correct answer)
- Actual wage rate vs. standard wage rate at actual hours
- Budgeted labor cost vs. actual labor cost
Correct answer: Standard hours allowed for actual output vs. actual hours worked, multiplied by standard rate
Labor efficiency variance = (Standard hours for actual output – Actual hours) × Standard rate, isolating efficiency from rate effects.
CPM Plant Operations Management 3
In Total Productive Maintenance (TPM), autonomous maintenance is primarily the responsibility of whom?