6 Types of Automated Storage and Retrieval Systems (AS/RS) for Increased Efficiency in Your Warehouse
Automated storage and retrieval (AS/RS) has been having a bit of a moment the last few years as its adoption has become more widespread in warehouses and order fulfillment operations. This is a trend that will only continue and strengthen going forward. But what exactly is AS/RS, how does it work, and what types of AS/RS technologies are available to help you make your operation more efficient?
What is AS/RS?
Automated storage and retrieval systems—often referred to as AS/RS, but sometimes also AS-RS or ASRS—are a kind of warehouse technology wherein goods are automatically brought out of, and placed back into, storage. This is typically achieved by pairing the technology with warehouse execution software (WES) that manages the process and helps warehouse personnel process orders.
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AS/RS brings with it a number of advantages that help you make your warehouse or order fulfillment operation more efficient, but perhaps the largest is the fact that it allows you to more smartly allocate personnel to higher-value tasks. By automating labor-intensive and repetitive tasks—such as product retrieval and replenishing, for example—with an AS/RS, those labor hours can now be reallocated to other important areas of your business.
Types of AS/RS Technology
Automated storage and retrieval systems come in two main flavors, or varieties: Unit-Load AS/RS and Mini-Load AS/RS. Each of these broad categories includes a number of different technologies, which we explore in more detail below.
Unit-load automated storage and retrieval systems typically handle larger loads of goods and material (including weights measuring in thousands of pounds). Often, this means that the AS/RS tech is handling and moving full or partial pallets or cases.
Unit-load AS/RS is a great option when pallet-level storage is limited and quick retrieval is critical.
Unit-load AS/RS can come in many forms, including:
- Fixed-Aisle Unit-Load AS/RS Cranes: In fixed-aisle unit-load AS/RS systems, pallet racks are arranged with narrow aisles between them. A crane travels between these aisles moving both vertically and horizontally to retrieve and store product. The crane is fixed to a single aisle of pallets.
- Movable-Aisle Unit-Load AS/RS Cranes: This type of AS/RS, consisting of a crane moving between narrow aisles of pallets, functions in much the same way as fixed-aisle AS/RS. The key difference is that it is not fixed to a specific aisle and can service multiple aisles.
Compared to unit-load AS/RS, mini-load AS/RS typically handles smaller loads of product. Instead of full pallets, this often translates into a mini-load AS/RS handling totes, trays, or cartons. These systems are sometimes also called “case-handling” or “tote-stacking” systems.
Mini-load AS/RS is especially well suited for operations that require storage locations for a large amount of SKUs but which lack the floor space required for traditional carton-flow shelving to provide a pick face for each SKU. Mini-load AS/RS systems can also be used to buffer and efficiently release/sequence product to picking or palletizing stations, and can be used to automatically replenish pick locations like carton-flow
Like Unit-Load AS/RS, Mini-Load AS/RS can come in many forms, including:
- Mini-Load AS/RS Crane: The mini-load AS/RS crane operates in the same basic way as unit-load AS/RS cranes, with a crane operating between narrow rows of goods. Instead of pallets, this system moves totes, cartons, or trays.
- Mini-Load AS/RS Shuttle: Mini-load AS/RS Shuttles deliver product via a shuttle that runs on a track in between a racking structure. They can operate on a single level or multiple levels depending on the needs of the operation, and can be battery- or capacitor-powered. When an item is requested, the shuttle drives to the location of the product and retrieves its tote/carton. It will then take the tote/carton directly to a workstation or transfer it to a conveyor to convey the tote/carton to a workstation.
- Carousel-based AS/RS: In this kind of AS/RS, totes or cartons are stored and retrieved from horizontal or vertical sorters by a device called an inserter extractor. The system operates by spinning into position until the bin containing the shelf where the product is to be stored or retrieved from is in position with the inserter extractor.
- Vertical Lift Module (VLM): Vertical Lift Modules are enclosed systems with an inserter extractor in the center and a column of trays on either side. The inserter extractor locates the necessary tray and delivers it to an operator, who completes an order, before the tray is returned.
The Bottom Line
By incorporating one or a number of the automated storage and retrieval systems (AS/RS) discussed above into your warehouse or order fulfillment operation, you can achieve a significant boost in efficiency, cost-savings, and productivity. Which technology ultimately makes the most sense for you to include in your operation depends on a number of factors including rate, your typical order, the type of product that you handle, and more. A systems integrator or warehouse design consultant can help you choose between the many options available to ensure that, whether you utilize a unit-load or mini-load system, you have a solution tailored to your operation’s own unique challenges and needs.