CPM MRP & Production Control 2 — Questions and Answers
Question 1: In MRP, what is the purpose of 'time-phasing' requirements?
- To stagger demand across shifts for labor balance
- To offset gross requirements by lead time so orders are placed at the right time (Correct answer)
- To phase out obsolete materials from inventory
- To synchronize production with customer shipping windows
Correct answer: To offset gross requirements by lead time so orders are placed at the right time
Time-phasing offsets gross requirements by the item's lead time so that planned order releases occur early enough to receive materials when needed.
Question 2: Which MRP input file specifies the raw materials, components, and sub-assemblies required to build one unit of a parent item?
- Master Production Schedule
- Item Master File
- Bill of Materials (Correct answer)
- Inventory Status File
Correct answer: Bill of Materials
The Bill of Materials (BOM) defines the parent-child relationships and quantities needed to produce each assembly level.
Question 3: A company has a gross requirement of 500 units, scheduled receipts of 100 units, and on-hand inventory of 75 units. What is the net requirement?
- 325 units (Correct answer)
- 425 units
- 575 units
- 500 units
Correct answer: 325 units
Net requirement = Gross requirement − Scheduled receipts − On-hand = 500 − 100 − 75 = 325 units.
Question 4: What does 'pegging' accomplish in an MRP system?
- Locks the MPS to prevent changes during a planning fence
- Traces a component's demand back to the parent order that generated it (Correct answer)
- Assigns machine capacity to specific work orders
- Calculates safety stock levels based on demand variability
Correct answer: Traces a component's demand back to the parent order that generated it
Pegging links a lower-level component requirement to the specific parent order that created the demand, supporting root-cause analysis of shortages.
Question 5: Which lot-sizing rule minimizes holding costs while potentially increasing setup costs?
- Fixed Order Quantity
- Lot-for-Lot (Correct answer)
- Period Order Quantity
- Economic Order Quantity
Correct answer: Lot-for-Lot
Lot-for-Lot orders exactly what is needed each period, eliminating excess inventory and holding costs but requiring a setup each time there is demand.
Question 6: In a closed-loop MRP system, which function provides feedback that actual capacity is insufficient to execute the MRP plan?
- Demand Management
- Capacity Requirements Planning (CRP) (Correct answer)
- Distribution Requirements Planning (DRP)
- Supplier Scheduling
Correct answer: Capacity Requirements Planning (CRP)
Capacity Requirements Planning compares planned work orders to available capacity and feeds back constraints so the MPS or MRP plan can be adjusted.
Question 7: What is 'nervousness' in an MRP system, and what is a common remedy?
- Excessive WIP on the shop floor; remedy is kanban pull
- Frequent, disruptive changes to planned orders from small demand shifts; remedy is time fences or firm planned orders (Correct answer)
- Inaccurate BOM data causing wrong requirements; remedy is BOM audits
- Stockouts caused by long lead times; remedy is safety stock
Correct answer: Frequent, disruptive changes to planned orders from small demand shifts; remedy is time fences or firm planned orders
MRP nervousness refers to large plan changes triggered by small demand variations; time fences and firm planned orders stabilize the schedule.
CPM MRP & Production Control 2
In MRP, what is the purpose of 'time-phasing' requirements?