Capacity Requirements Planning (CRP)
Material Requirements Planning (MRP) provides the foundation for calculating Capacity Requirements Planning (CRP), a tool used to complete the master schedule.
- MRP looks at the inventory and at orders to generate the demands
- CRP uses routings and work centers and how to meet those demands.
Capacity Requirements Planning (CRP) calculates workload for a Work center or Machine. It does this by exploding the routings and processes for MRP planned and confirmed orders and determining start and due dates for each operation, using the work center and shop calendars and a technique called back scheduling.
The capacity for a work center is the number of machines or personnel available for that work center, defined in Work Center Maintenance, multiplied by work hours, defined in the shop floor calendar.
Capacity Requirements Planning (CRP) Execution
Generate capacity requirements for manufacturing orders using Recalculate Capacity Plan. CRP explodes the routings and processes for the orders you select. It then determines capacity requirements for selected manufacturing orders by scheduling their operations. CRP determines operation start and due dates using the work center and shop calendars and a technique called back scheduling.
- When Capacity Requirements Planning (CRP) back-schedules orders, it takes the due date of an WO and schedules each of its operations from the last operation in the order routing or process backward to the first one.
- Capacity Requirements Planning (CRP) assigns each operation a start date and a due date, using the operation lead time components “Pre Production” and “Post Production” to calculate operation start dates. The start date of an operation is the same as the due date of the previous operation.
- Capacity Requirements Planning (CRP) calculates run times based on the actual order quantity—that is, the order quantity less the quantity completed
- When manufacturing order operations overlap, the system smoothes the scheduled start and due dates to prevent the scheduled due date for one operation from occurring later than the due date for a subsequent operation.
- MRP calculates manufacturing order release dates using a manufacturing lead time that is based on an average order quantity defined in Item Planning.
- If the order quantities used in CRP calculations differ from this average quantity, CRP may schedule the start date for an order’s first operation before the release date for that order. When this occurs, a message displays to alert you of the conflict. You can resolve such conflicts by adjusting the order release or due date and rerunning CRP.
Work Center Load Reports
You can generate load reports by work centre. Capacity Requirements Planning (CRP) determines load hours for a work center based on Pre and Post Production efforts. CRP determines the load an operation exerts on a work center using the following calculation:
Operation Load = Setup Time + (Run Hours/Unit x Quantity Open)
The quantity open for an operation is the order quantity minus any quantities reported complete.
Adjusting Capacity and Load is as below.
- If a work Center or machine is over or under loaded, you can modify either its capacity or the timing or amount of the load.
- Adjusting Capacity – Add or subtract workday hours as needed for work center or shop calendars.
- Adjusting Machine Load and machine activities – Adjust the timing or amount of load by modifying:
- Work order due dates
- Operation lead time components