Shelf life in Simulation

You can assign a shelf life to a product to control when that product expires and may no longer be used. Enter a value in the Shelf Life column in the Products table to define how long after production the product expires. The Shelf Life is required to be an integer (the number of days till expiry). When there is no value for Shelf Life, the product does not expire.

Products begin to age once production is complete. Different batches of a product can have different expiry dates, based on when they are completed. At the point a manufacturer sends product to a distribution center immediately upon completion of production, the age is 0. Products can expire either on-site or in-transit. For products expiring in-transit, this is attributed to the source location and will be reflected in the source expiration statistics.

If a product expires and a replenishment order is placed, the replenishment order has the same Internal Tracking ID as that of the original order (the one that expired).

Simulation will look to prioritize project batches to use those closer to the end of shelf life first. This functionality is available when using the "Simulation" problem type.

Shelf life outputs

A number of Simulation output tables have columns that report details about shelf life. The information reported is as follows:

• Expired Units - This defines the number of units that have expired based on reaching the end of their shelf life. They may have expired at the site, in the case of the Site Product Summary, or while in transit as with InterSite Shipment Flows and Customer Shipment Flows.
• Outbound Average Age - This is the weighted average age in days of a product batch when it leaves the source. The column is available on the InterSite Shipment Flows and Customer Shipment Flows tables. Since aging does not begin until production is complete, products shipped immediately upon completion of production will incur no Outbound Average Age from the manufacturer.
• Inbound Average Age - This is the weighted average age in days of a product batch when it arrives at the destination. The column is available on the InterSite Shipment Flows and Customer Shipment Flows tables. This column takes into consideration the transit times from the production site to this destination. For example, if you have a path from MFG -> Hub -> DC, the Inbound Average Age when it reaches the DC considers both the travel time from MFG to Hub and from Hub to DC.
• Average Age - This column provides the weighted average age of a product when it arrives at the customer. It is available in the Customer Product Summary table.
• Total Expired Units - This column displays the number of units that have expired based on reaching the end of their shelf life. The value is totaled at the site level in the Simulation Site Summary or at the network level in the Simulation Network.
• Total Expired Value - This column displays the total of the expired units * Unit Price from the Products table for the affected products. The value is totaled at the site level in the Simulation Site Summary or at the network level in the Simulation Network Summary.
• Expired Quantity - This defines the number of units that have expired based on reaching the end of their shelf life. This column is available in the Shipment Handling Log and Shipment Transactions tables.

In addition to these columns, the Expired Product Detail table provides the quantity of product expiring at the Site-Product-Time level.

Shelf Life example

In a simple network with a manufacturer (MFG), distribution center (DC) and customer (CZ), assume the following values in tables:

Products

Customer Orders

Production Policies

Inventory Policies

Transportation Policies

The customer order is placed on January 1, 2020 at 1 AM and the following activities occur:

• January 2 - Based on the daily review period, the order is picked up and production starts. There is currently no inventory at either the MFG or DC.
• January 5 - Production is complete and 75 units are shipped from the MFG to the DC.
• January 6 - 75 units arrive at the DC and 25 units are shipped from the DC to the CZ. Production for an additional 75 units is complete. The MFG has 100 units in inventory and the DC has 50 units.
• January 7 - 25 units arrive at the CZ.
• February 4 - The product shelf life is reached for 25 units in inventory at the MFG and 50 units in inventory at the DC. These products expire. The Expired Product Detail table shows the information in these records:

  Site	Product	Time	Quantity
  DC	SKU1	2/4/2020 12:00 AM	50.00
  MFG	SKU1	2/4/2020 12:00 AM	25.00

• February 5 - The remaining 75 units in inventory at the MFG reach their shelf life and expire. The Expired Product Detail table shows the information in these records:

  Site	Product	Time	Quantity
  MFG	SKU1	2/5/2020 12:00 AM	25.00
  MFG	SKU1	2/5/2020 12:00 AM	50.00

If the model horizon has not been reached, production occurs to satisfy the inventory requirements at the sites.