CPIM - Certified in Planning and Inventory Management Detailed Scheduling Questions and Answers — Questions and Answers
Question 1: A work center's planned input is 100 standard hours, and the planned output is 100 standard hours. Over the past week, the actual input was 90 hours, and the actual output was 80 hours. What is the immediate conclusion a production planner should draw using input/output control?
- The work center is a bottleneck because its output is less than its input.
- The work center's capacity should be permanently increased.
- The work center performed with 80% efficiency.
- A backlog of 10 standard hours has been created this week. (Correct answer)
Correct answer: A backlog of 10 standard hours has been created this week.
Input/output control monitors the relationship between the planned and actual inputs and outputs of a work center. The change in the queue (or backlog) is calculated by subtracting actual output from actual input. In this case, 90 hours (actual input) - 80 hours (actual output) = 10 hours. This means the queue of work waiting for this center has increased by 10 standard hours this week.
Question 2: A manufacturing scheduler is using a finite loading approach. Which of the following is a key characteristic of this detailed scheduling technique?
- Work is scheduled without regard to the capacity of work centers.
- The schedule is created by backward scheduling from the order due date, assuming unlimited resources.
- It creates a realistic schedule by considering the actual capacity of resources. (Correct answer)
- The primary goal is to identify and highlight resource overloads for manual adjustment.
Correct answer: It creates a realistic schedule by considering the actual capacity of resources.
Finite loading, or finite capacity scheduling, creates a realistic and achievable production schedule by taking into account the actual, limited capacity of each work center. It will not schedule work if the necessary capacity is not available, pushing the job to a later time when capacity exists. Infinite loading, in contrast, ignores capacity constraints.
Question 3: In a job shop environment with several orders competing for time on a single machine, which dispatching rule would prioritize the job that is most likely to be completed the soonest?
- Earliest Due Date (EDD)
- First Come, First Served (FCFS)
- Shortest Processing Time (SPT) (Correct answer)
- Critical Ratio (CR)
Correct answer: Shortest Processing Time (SPT)
The Shortest Processing Time (SPT) rule sequences jobs based on the time required to perform the operation, with the shortest job being run first. This rule is effective at minimizing overall completion time and work-in-process inventory.
Question 4: Which of the following detailed scheduling activities involves determining the specific order in which jobs will be run at a particular work center?
- Capacity Requirements Planning (CRP)
- Material Requirements Planning (MRP)
- Sales and Operations Planning (S&OP)
- Operation Sequencing (Correct answer)
Correct answer: Operation Sequencing
Operation sequencing, often managed through dispatching rules, is the process of determining the order in which to process jobs that are waiting in a queue at a work center. MRP and CRP are higher-level planning functions that determine what and when to produce and the capacity required, but not the specific job-by-job sequence on the shop floor.
Question 5: A production planner is reviewing the output of their Capacity Requirements Planning (CRP) system. The report shows that a key work center is overloaded for the next two weeks. According to the principles of detailed scheduling, what is the MOST appropriate next step?
- Ignore the overload as it is likely a short-term issue.
- Immediately authorize overtime and subcontracting.
- Use finite scheduling to create a realistic plan that respects capacity constraints. (Correct answer)
- Revise the Master Production Schedule (MPS) to reduce demand.
Correct answer: Use finite scheduling to create a realistic plan that respects capacity constraints.
CRP identifies mismatches between required capacity and available capacity. When an overload is detected, the next logical step in detailed scheduling is to use a technique like finite scheduling to resolve the overload by re-sequencing jobs, moving some jobs to different time periods where capacity is available, or using alternate work centers. While options like overtime or changing the MPS might be necessary, creating a realistic, capacity-constrained schedule first is the most direct detailed scheduling action.
Question 6: Backward scheduling is a common technique used in detailed scheduling. What is the primary starting point for this method?
- The availability of the bottleneck resource.
- The order's required due date. (Correct answer)
- The earliest possible material availability date.
- The start date of the first operation in the routing.
Correct answer: The order's required due date.
Backward scheduling starts with the customer's required due date and works backward in time, scheduling the last operation first, then the second-to-last, and so on, to determine the required start date for the order. This method is often used with MRP systems to ensure materials arrive just in time for production.
CPIM - Certified in Planning and Inventory Management Detailed Scheduling Questions and Answers
A work center's planned input is 100 standard hours, and the planned output is 100 standard hours.
Over the past week, the actual input was 90 hours, and the actual output was 80 hours.
What is the immediate conclusion a production planner should draw using input/output control?