About Push Planning

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.
• 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 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 doesn't calculate a start date in the past, and that has a projected completion date that is within the Pull Tolerance days of being the optimal date.