How APS Replenishes Safety Stock
This topic describes how APS plans safety stock replenishment. See MRP Overview for a description of how MRP plans safety stock.
APS will plan to keep inventory at or above safety stock. When safety stock is set up correctly, the system will generate one safety stock replenishment order for any item that drops below safety stock with the following attributes:
- Order Quantity: The order quantity, adjusted for the item's order minimum and multiple values, will ensure the inventory level remains at or above safety stock over the whole planning horizon.
- Projected Date: The projected date of the safety stock order is calculated as APS normally does for purchased (using all the lead times applied to the PCAL) and manufactured items (using the item's BOM).
- Due Date: The due date of the safety stock is calculated several ways. See the Due Date section below for more details.
Due Date Calculation
For purchased Items:
- Due date = Date & Time of APS plan + Lead time (using the PCAL shop calendar)
- Lead time = Fixed + Dock-to-stock + Paperwork lead times
For manufactured items:
- Due date = Date & Time of APS plan + Lead time, using the PCAL shop calendar
- Lead time = Fixed + Dock-to-stock + Paperwork + (Variable * Safety Stock level)
Safety Stock Processing
- Before the first APS Planning step, the BOMs for all manufactured items with safety stock defined are examined, and the quantity needed for any components is recorded. For each item, those quantities are added together with that item’s original safety stock quantity to become the new internal safety stock level. This new safety stock level works with the Time Fence to keep enough inventory and near-term supply available to additionally satisfy the needs of parent items with safety stock.
- After the demands have been planned, the safety stock orders for manufactured and transfer items are planned based on the original safety stock level of the item. Each item is processed in the order specified in the item’s Low Level Code field, on the Items form, from top to bottom. If the Safety Stock Sequence Rule is selected, a secondary sort rule is applied to items with the same Low Level Code.
- When a safety stock order is planned, if it creates a new PLN with excess supply available, the manufactured part swapping logic evaluates future PLNs for the item. If the excess supply from the safety stock PLN can satisfy the demand of a future PLN, that future PLN is removed. Manufactured part swapping does not have to be enabled for the item for this to occur.
- After the safety stock orders have been planned, manufactured items that have a zero safety stock level, but that gained safety stock as a result of the BOM examination, are evaluated to see if they have remaining inventory or near-term supply that was protected by a time fence. If they do, the manufactured part swapping logic determines if any future PLNs can be replaced by a use of inventory or near-term supply. Manufactured part swapping does not have to be enabled for the item for this to occur.
- If Days Supply is enabled, the days supply consolidation occurs and the planning process concludes. The results of the safety stock planning are consolidated with the other demands.
- Safety stock for purchased items is calculated during the purchased part swapping phase.
Fields Directly Related to Safety Stock Replenishment
The fields listed below either affect the way the system generates planned orders to replenish safety stock, or they are used, along with the safety stock value, to calculate a value used for another feature.
| Field | Appears On |
|---|---|
| Consider Negative On Hand | Planning Parameters |
| Time Fence Rule | Items |
| Time Fence Value | Items |
| Safety Stock | Item/Warehouse |
| Paper Work Lead Time | Items |
| Fixed Lead Time | Items |
| Dock-to-Stock Lead Time | Items |
| Order Minimum | Items |
| Order Multiple | Items |
| Order Maximum | Items |
| Pull-Up Safety Stock Rule | Items |
| Pull-Up Safety Stock Value | Items |
| Days Supply Planning | Planning Parameters |
| Safety Stock Sequence Rule | Planning Parameters |
| Low Level Code | Items |
About Reorder Point Items and Safety Stock
Reorder Point items are usually inexpensive, high-volume items (such as nails, bolts, etc.) that you want to track and replenish differently than normal items. The system does not generate safety stock replenishment planned orders for Reorder Point items. However, the "On hand below safety stock" exception is generated when the system creates a reorder-point planned order.