About Push Planning
This topic applies only to APS.
If the system cannot find enough on-hand inventory, planned supplies,
or resource capacity to pull
plan a demand within the time between the due date and the current
date, it instead push plans the demand forward from the current
date. The system push plans a demand according to this sequence:
- Calculate the end-item quantity needed. Allocate on-hand inventory
to satisfy the end-item demand quantity.
NOTE: When APS
allocates inventory to a demand, it considers the combined total of
all inventory at all warehouses (at a given site) in which the Dedicated
Inventory option is NOT selected.
- Pass any remaining end-item demand quantity to the component materials,
down to the lowest levels in the bill of material. Allocate on-hand
inventory to satisfy the demand quantity of the components.
- Plan the component materials in the lowest levels of the bill of
material. This step consists of planning steps in the routing for
manufactured components or moving out to the lead time for purchased
components. For manufactured components, each operation in the component's
routing is planned in forward sequence (starting with the first operation).
The system checks several resource combinations to find the combination
that can finish the work the fastest (the number of combinations to
check is specified in the Push
Iterations planning parameter). The result is the component material's
earliest-possible completion date, which sets the start date of its
parent end-item's first operation.
- Search for available planned supplies, starting with the current
date and searching out to the date calculated in the previous step.
Allocate supplies only if the entire demand quantity can be satisfied.
- When forward planning is finished, the end-item completion date
becomes the demand's Projected date.
- The system may plan non-critical operations earlier than they are
actually needed to meet the demand. To optimize the plan, the system
runs a series of additional pull-planning iterations starting from
the demand's new projected date.
- Pull plan starting from the projected completion date. If this
plan fails (that is, if it projects a start date in the past),
the system then pull plans the demand from the end of the Plan
Horizon.
- Incrementally pull plan between the projected completion date
from the above push plan (or between the need date and the Plan
Horizon, if the above push failed) and the demand's need date
to find a feasible plan that is within Pull Tolerance (see Planning
Pull Tolerance or ATP/CTP
Pull Tolerance) days of the optimal projected date. For example,
the first iteration pulls from the midpoint between the projected
date and the need date. If that pull plan succeeds, the next iteration
pulls from the midpoint between that new projected date and the
need date. The process incrementally moves closer to the need
date until it finds a plan that a) doesn't calculate a start date
in the past AND b) has a projected completion date that is within
the Pull Tolerance days of being the optimal date.
NOTE: If the system
is unable to push plan a demand in the time between the current date and
the end of the Plan Horizon, the demand is displayed as "blocked"
on the planning output forms and reports and cannot be planned. See About
Blocked Demands for more information.
Related Topics
APS Overview
About
the Planning Process