ASRS (Automated Storage and Retrieval System) is a high-density automated pallet storage system.
Detailed Definition
An ASRS combines storage racking, automated machines such as stacker cranes or shuttles, conveyors and control software to put away and retrieve loads without a driver. Unit-load systems handle full pallets, while mini-load systems handle totes and cases. Because cranes can work in very tall, narrow aisles, a pallet ASRS can store more loads per square foot of floor than conventional rack with forklift aisles. They are often used in cold storage, food and beverage, and manufacturing where volume is high and labor or space is limited.
Pallet quality in an ASRS
An automated system has little tolerance for pallet problems. A broken bottom board, a protruding nail, or a load that leans can jam a conveyor or crane and stop a whole aisle. For that reason most unit-load ASRS installations include:
- a profile or dimension check at the infeed that rejects overhanging or tall loads
- a weight check against the system's rated load
- a defined pallet type, often a single footprint and entry style
- inspection or a dedicated internal pallet, sometimes called a slave pallet, for poor-quality inbound pallets
Planning questions
Ask the integrator which pallet types and orientations the system is designed for, how rejects are handled, and what happens during maintenance or power loss. Fire protection for tall automated racks needs early coordination with the authority having jurisdiction. Mixed recycled pallet stock can cause frequent rejects, so many users specify new, high-grade recycled or pooled pallets for automated storage.
Cold storage use
Freezer warehouses often favor ASRS because it reduces the time people and equipment spend in the cold and makes full use of tall, expensive refrigerated space. Pallets for freezer systems should resist ice buildup and not warp, and wet or frozen wood can change dimensions enough to cause rejects.
Authoritative Sources
- Material Handling Institute (MHI): the largest US trade association for material handling, logistics, and supply chain technologies.
Related Glossary Terms
Frequently Asked Questions
What is a slave pallet in an ASRS?
A slave pallet is a dedicated, high-quality pallet or platform that stays inside the automated system. Inbound loads on mixed or damaged pallets are placed on top of it so the crane and conveyors always handle a known, consistent base. It adds a handling step and cost, but reduces jams caused by poor pallets.
Can an ASRS handle different pallet sizes?
Some can, if designed for it, but each additional size or orientation affects rack design, conveyors and controls. Many systems are built for one or two pallet types, such as 48x40 in North America or 1200x800 mm in Europe. Define your pallet mix early in the project, because changing it later is costly.