The manufacturing order planned through the material planning (MRP or parts explosion) is usually submitted to the administration division or the person in charge of administration that comprehensively control the manufacturing division, and the validity of its capacity and load is first determined. The manufacturing order is created for each item using B/M based on the production schedule through the material planning, and thus at this point the concept of process is not existing yet. But items are actually produced through a number of processes. Capacity Requirements Planning refers to the planning where the load for each process is grasped according to the manufacturing order, the adjustments are made, and then the work of each process is planned.
It is necessary to set the capacity after considering the current situation, in order to make Capacity Requirements Planning more practical. In this planning, the following three capacities are used:
- Standard Capacity: the ability to produce items in a standard process. The standard capacity is usually set for each process, and such time margin as morning meeting time and break time as well as attendance rate are also considered. In addition, Capacity may be registered for each operation date.
- Maximum Capacity: the ability to produce the maximum quantity/quality of items in a process. It can be set according to the actual performance or as an overload tolerance.
- Set Capacity: the ability to be set based on the relationship between the maximum capacity and load.
When setting the capacity, such factors as overtime work, shift, and the increase or decrease in staff transfer are considered.
Generally, capacity demand plan can be divided into four functions.
- Process spread: MRP calculate the amount of items required, but the actual operation instruction is for each process, Therefore, items level plan need to be broken down into process level plan. This subdivide function is called process spread.
- Load accumulation： Orders generated during process spreading called work orders. The work time that calculated when process spreading is recorded into work orders, the time is seen as the job load, calculate the load of each project.
- Load adjustment： Load adjustment happens in the earliest start time (get ready materials, the earliest time you can get to work) to latest start time (the latest start time that do not occur late delivery) scale.
- Ability adjustment： In case that unable to deal with by adjusting the load, overtime work, change shift, outsourcing…est. can be considered.
On base of these functions and planner’s adjustment to calculate capacity demand. work orders that generated in the plan, will be succeeded to the work plan.
Rough-cut Capacity Planning RCP or RCCP
It is usually called RCP for short, and is a plan to check the validity of factory production capacity in light of the production plan. It is used in both make-to-stock production and make-to-order one. In this planning, whether the capacity meets the load quantity of each important process or not is considered and planned by identifying the bottleneck process in a factory based on the routings and exploring it to each process.
Using this plan, the production plan and its capacity are reviewed, and the results are taken over to MRP (in case of make-to-stock production), or the final assembling planning (in case of make-to-order production). The load status list by bottleneck process is usually created through Rough-cut Capacity Planning.
RCCP verifies that you have sufficient capacity available to meet the capacity requirements for your master schedules. RCCP is a long-term plan capacity planning tool that marketing and production use to balance required and available capacity, and to negotiate changes to the master schedule and/or available capacity. You can change your master schedules by changing master schedule dates and increasing or decreasing master schedule quantities. You can change your available capacity by adding or removing shifts, using overtime or subcontracted labor, and adding or removing machines.
RCCP is a gross capacity planning technique that does not consider scheduled receipts or on-hand inventory quantities when calculating capacity requirements. Your rough cut capacity plans are therefore a statement of the capacity required to meet your gross production requirements.
Use RCCP to validate your master schedules against key and critical resources before you use the planning process to generate detailed MRP plans. This ensures that you use a realistic, achievable master schedule to drive the planning process. You can perform rough cut capacity planning at two levels:
- Use routing-based RCCP if you want to plan rough cut capacity by resource. Required and available capacity are stated in hours per week per resource.
- Use rate-based RCCP if you want to plan your rough cut capacity by production line. Required and available capacity are stated by production rate per week per line.