Time Fence Control
Time fence control is a policy or guideline you establish to note where various restrictions or changes in operating procedures take place. For example, you can easily change the master production schedule for an item beyond its cumulative lead time, with little effect on related material and capacity plans. However, changes inside the cumulative lead time cause increasing difficulty, to a point where you should resist such changes because of their effect on other operations. You can use time fences to define these points of policy change. Oracle Master Scheduling/MRP and Supply Chain Planning offers three types of time fences: the demand time fence, planning time fence, and release time fence.
Defining Time Fences for Items
You define demand, planning, and release time fence days when you define an item. You can define the demand, planning, and release time fence for the item as either the cumulative manufacturing lead time, cumulative total lead time, total lead time, or a user-defined time fence.
Oracle Master Scheduling/MRP and Supply Chain Planning defines one boundary of the time fence for an item as the current date, and the other boundary as value of the cumulative manufacturing lead time, cumulative total lead time, total lead time, or a user-defined time.
For example, suppose you define the demand time fence for an item as the cumulative manufacturing lead time and the planning time fence as a user-defined time. The planning process considers the demand time fence (in workdays) of the item as the current date up to the cumulative manufacturing lead time of the item. The planning process considers the planning time fence (in workdays) of the item as the current date up to the time fence value you enter. See: Defining Items.
Establishing Time Fence Control
You establish demand and planning time fence control when you set up Oracle Master Scheduling/MRP and Supply Chain Planning. See: Defining Planning Parameters.
You establish release time fence control when you define a plan or schedule name. You can also override time fence control for individual material plans or master schedules when you generate a DRP, MRP or MPS. See: Defining a Schedule Name, and Defining MRP Names.
Demand Time Fence Control
The demand time fence is bordered by the current date and a date within which the planning process does not consider forecast demand when calculating actual demand. Within the demand time fence, Oracle Master Scheduling/MRP and Supply Chain Planning only considers actual demand. Outside the demand time fence, the planning process considers forecast demand. You can specify whether to use demand time fence control when loading a master schedule and launching the planning process.
Planning Time Fence Control
The planning time fence is bordered by the current date and a date within which the planning process does not alter the current material plan or master schedule. You can specify whether to use planning time fence control when launching the planning process.
For discrete items within the planning fence, the planning process does not reschedule in (create earlier) order due dates or create new planned orders for the item to satisfy net demand requirements. However, the planning process can reschedule out or cancel an order when it determines that such orders create excess supply. For discrete items outside the planning time fence, the planning process can generate suggestions to create, change, and reduce entries on the master schedule or the material requirements plan.
For repetitive items, Oracle Master Scheduling/MRP and Supply Chain Planning restricts the planning process to suggest rates of production within the planning time fence that differ from the current aggregate repetitive schedule by no more than the acceptable rate increase and acceptable rate decrease you defined for the item. If either the acceptable rate increase or decrease value is undefined, the planning process is not restricted from increasing or decreasing the repetitive schedule respectively.
You can choose whether to display a warning when you define or update MPS entries that violate the planning time fence, or when you define or update MDS entries that violate the demand time fence. Set the MRP:Time Fence Warning profile option to Yes. See: Setting Your Personal User Profile.
Planning Time Fences for Requisitions
Purchase requisitions and internal requisitions are not subject to planning time fence processes.
Release Time Fence Control
The release time fence is bordered by the current date and a date within which the planning process automatically releases planned orders to Oracle Work in Process as discrete jobs or to Oracle Purchasing as purchase requisitions. You can specify whether to use release time fence control when defining your plan name.
The planned orders must meet the following auto-release criteria:
- the new due date lies within the auto-release time fence
- the lead time is not compressed
- the orders are for standard items (will not release models, option classes, and planning items)
- the orders are not for Kanban items
- the orders are for DRP planned items in a DRP plan, MPS planned items in an MPS plan, or MRP planned items in an MRP plan See: Auto-release Planned Orders.
Auto-release of suggested repetitive schedules is not applicable to repetitively planned items. No material availability check is performed before WIP jobs are released.
- the release time fence option is defined as anything other than Do not auto-release, Do not release (Kanban), or Null
Time Fences and Firm Orders
A firm order is an order that is frozen in quantity and time (unavailable for rescheduling). Oracle Master Scheduling/MRP and Supply Chain Planning automatically creates a planning time fence for the firm order if the firm order exists after the planning time fence date. There are two methods you can use to firm an order that creates a time fence: you can firm a planned order or firm a discrete job in the Planner Workbench, or you can firm a discrete job or purchase order within Oracle Work in Process and Oracle Purchasing directly.
Oracle Master Scheduling/MRP and Supply Chain Planning creates a time fence for a firm order because it implies that resources committed to meeting the firm order would be unavailable for orders scheduled earlier.
Attention: You can use the profile option MRP:Firm Planned Order Time Fence to indicate whether to form natural time fences for your MRP firm planned orders when launching the planning process. Oracle Master Scheduling/MRP and Supply Chain Planning does not create a time fence for an MRP firm planned order if you set this profile option to no. See: Setting Your Personal User Profile..