Automation Delivers On-Time Shipments For USPS Holiday Parcel Annex

During the holiday season, the Seattle United States Postal Service (USPS) processing center receives so many oversized parcels it has to lease 150,000 square feet of warehouse space with 30 dock doors for a few weeks to process them. In the past, the Seattle USPS used a manual sorting system, but increasing volumes demanded a more efficient solution. The Seattle USPS turned to automation specialist Olympic Controls (Wilsonville, OR) to design an automated 'scan while you band' solution that was 100% portable.

When the Seattle USPS opened its holiday annex in December 2003, after Olympic Controls' installation of the solution, it was operating a fully automated system. It was complete with hundreds of feet of roller conveyor lines, eight weigh scale stations, and two network hubs connected to the main facility via a wireless network. The entire system was set up in three weeks and broken down in a few days.

With the new system, large packages are unloaded at the dock doors and the contents are placed on a conveyor and routed to one of eight weigh stations. The bar code on the package is scanned by a fixed-mount Microscan Systems Incorporated (Renton, WA) MS-880 bar code reader. The data is sent to a Siemens (Munich, Germany) Simatic S7 PLC (programmable logic controller), where it is held until the package reaches a stable weight. Once the weight is logged and matched with the bar code data, the data is sent to a network hub connected to Seattle USPS' wireless network, known as Starship. Starship looks at the ZIP code to find the best possible transportation route for the package and then tells the computer the information to print on the label. An operator then places the label on the package. Once the bar code readers scan the bar code, the package is routed to the right location for pickup by the designated carrier.

The MS-880 bar code readers were selected for their programmable read range and their ability to read poor-quality bar codes. Since nearly 25% of the packages arrive without bar codes, a keyboard was connected to the same data port as the bar code reader, enabling the operator to key in the ZIP code of packages missing bar codes.

The automated system allowed the USPS to handle three times the normal volume while reducing the item cycle time and the number of people required to perform operations.