Section H: Capacity Management Flashcards
What two modules encompasses Capacity Management?
Capacity management includes capacity planning and capacity control.
Capacity
Capacity : The capability of a worker, machine, work center, plant, or organization to produce output per time period. Capacity required represents the system capability needed to make a given product mix (assuming technology, product specification, etc.). As a planning function, both capacity available and capacity required can be measured in the short term (capacity requirements plan), intermediate term (rough-cut capacity plan), and long term (resource requirements plan). Capacity control is the execution through the I/O control report of the short-term plan.
Capacity management
Capacity management : The function of establishing, measuring, monitoring, and adjusting limits or levels of capacity in order to execute all manufacturing schedules (i.e., the production plan, master production schedule, material requirements plan, and dispatch list).
Capacity planning
Capacity planning : The process of determining the amount of capacity required to produce in the future. This process may be performed at an aggregate or product-line level (resource requirements planning), at the master-scheduling level (rough-cut capacity planning), and at the material requirements planning level (capacity requirements planning).
Capacity available
Capacity available : The capability of a system or resource to produce a quantity of output in a particular time period.
Capacity required
Capacity required : The capacity of a system or resource needed to produce a desired output in a particular time period.
Load
Load : The amount of planned work scheduled for and actual work released to a facility, work center, or operation for a specific span of time. Usually expressed in terms of standard hours of work or, when items consume similar resources at the same rate, units of production.
What is the unit of Capacity?
Capacity is a rate, not a quantity.
standard time
standard time as follows: The length of time that should be required to (1) set up a given machine or operation and (2) run one batch or one or more parts, assemblies, or end products through that operation. Used in determining machine requirements and labor requirements. Assumes an average worker who follows prescribed methods, and allows time for personal rest to overcome fatigue and unavoidable delays. Also frequently used as a basis for incentive pay systems and as a basis of allocating overhead in cost accounting systems.
the general steps in the iterative capacity planning process…
- Calculate the capacity available. (This will be the rated or demonstrated capacity, as calculated in the next topic.)
- Calculate the load per time bucket (capacity required), and determine differences between capacity available and capacity required.
- Resolve differences. Adjust available capacity first, and, if necessary, change the priority plan to match capacity available.
capacity requirements planning (CRP)
capacity requirements planning (CRP)
The function of establishing, measuring, and adjusting limits or levels of capacity. In this context, the term refers to the process of determining in detail the amount of labor and machine resources required to accomplish the tasks of production. Open shop orders and planned orders in the MRP system are input to CRP, which through the use of parts routings and time standards translates these orders into hours of work by work center by time period. Even though rough-cut capacity planning may indicate that sufficient capacity exists to execute the MPS, CRP may show that capacity is insufficient during specific time periods.
routing
routing in part as follows: Information detailing the method of manufacture of a particular item. It includes the operations to be performed, their sequence, the various work centers involved, and the standards for setup and run. In some companies, the routing also includes information on tooling, operator skill levels, inspection operations and testing requirements, and so on.
manufacturing (shop) calendar
manufacturing calendar, also called a shop calendar, which the Dictionary defines as follows: A calendar used in inventory and production planning functions that consecutively numbers only the working days so that the component and work order scheduling may be done based on the actual number of workdays available.
work center
work center, also called a load center, as follows: A specific production area, consisting of one or more people and/or machines with similar capabilities, that can be considered as one unit for purposes of capacity requirements planning and detailed scheduling.
lead time
lead time in part as follows: A span of time required to perform a process (or series of operations).… Individual components of lead time can include order preparation time, queue time, processing time, move or transportation time, and receiving and inspection time.
queue
Queue : A waiting line. In manufacturing, the jobs at a given work center waiting to be processed. As queues increase, so do average queue time and work-in-process inventory.
setup time
Setup time : The time required for a specific machine, resource, work center, process, or line to convert from the production of the last good piece of item A to the first good piece of item B.
Setup
Setup : 1) The work required to change a specific machine, resource, work center, or line from making the last good piece of item A to making the first good piece of item B. 2) The refitting of equipment to neutralize the effects of the last lot produced (e.g., teardown of the just-completed production, preparation of the equipment for production of the next scheduled item).
run time
Run time : The time required to process a piece or lot at a specific operation. Run time does not include setup time.
wait time
Wait time : The time a job remains at a work center after an operation is completed until it is moved to the next operation. It is often expressed as a part of move time.
move time
Move time : The time that a job spends in transit from one operation to another in the plant.
transit time
Transit time : A standard allowance that is assumed on any given order for the movement of items from one operation to the next.
Internal setup time
Internal setup time : The time associated with elements of a setup procedure performed while the process or machine is not running.
External setup time
External setup time : The time associated with elements of a setup procedure performed while the process or machine is running.
process batch
process batch , which the Dictionary defines as The quantity or volume of output that is to be completed at a workstation before switching to a different type of work or changing an equipment setup.
In a job shop environment (also known as a functional or intermittent layout, discussed in section A of the learning system text), which one of these lead time elements typically accounts for most of the lead time?
In a job shop or functional layout, queue is typically the largest element of lead time, accounting for 85 percent to 95 percent of the total manufacturing lead time.
Why is queue typically the largest element of lead time?
There are many reasons, but most of them center on the problem of coordinating and organizing material flow. This is a problem, particularly in a job shop environment, where orders take different times in different work centers, which also are being scheduled to make other components and subassemblies.
How can queue be managed?
Production activity control is responsible for managing the queue by regulating the flow of work into and out of work centers. IF the number of order waiting to be worked on (load) is reduced, so is the queue time, the lead time, and work-in-process. Increasing capacity also reduces queue. Production activity control must manage both the input of orders to the production process and the available capacity to control queue and work-in-process
Available time
Available time (hours) = number of machines x hours per day x days per week
Utilization rate
Utilization = hours actually worked ÷ available time
Efficiency
Efficiency = Standard Hours Produced ÷ Hours Actually Worked
Rated capacity
Rated capacity in standard hours = available time × utilization × efficiency
