Automated storage and retrieval system
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An automated storage and retrieval system (ASRS or AS/RS) consists of a variety of computer-controlled methods for automatically placing and retrieving loads from specific storage locations.Automated Storage and Retrieval Systems (AS/RS) are typically used in applications where there is a very high volume of loads being moved into and out of storage where storage density is important because of space constraints, and where no value adding content is present in this process.
Overview
ASRSs are categorized into three main types: single masted, double masted, and man-aboard. Most are supported on a track and ceiling guided at the top by guide rails or channels to ensure accurate vertical alignment, although some are suspended from the ceiling. The 'shuttles' that make up the system travel between fixed storage shelves to deposit or retrieve a requested load (ranging from a single book in a library system to a several ton pallet of goods in a warehouse system). As well as moving along the ground, the shuttles are able to telescope up to the necessary height to reach the load, and can store or retrieve loads that are several positions deep in the shelving.
To provide a method for accomplishing throughput to and from the ASRS and the supporting transportation system, stations are provided to precisely position inbound and outbound loads for pickup and delivery by the crane.
Man-aboard AS/RS
A man-aboard AS/RS offers significant floorspace savings. This is due to the fact that the storage system heights are no longer limited by the reach height of the order picker. Shelves or storage cabinets can be stacked as high as floor loading, weight capacity, throughput requirements, and/or ceiling heights will permit. Man-aboard automated storage and retrieval systems are far and away the most expensive picker-to-stock equipment alternative. Aisle-captive storage/retrieval machines reaching heights up to 40 feet cost around $125,000. Hence, there must be enough storage density and/or productivity improvement over cart and tote picking to justify the investment. Also, because vertical travel is slow compared to horizontal travel, typical picking rates in man-aboard operations range between 40 and 250 lines per person-hour. The range is large because there is a wide variety of operating schemes for man-aboard systems. Man-aboard systems are typically appropriate for slow-moving items where space is fairly expensive.
Vertical Lift Systems
The VLS is a computer controlled automated vertical lift, storage and retrieval system. Functionally, stock within the VLS remains stationary on front and rear tray locations. On request a movable extractor unit travels vertically between the two columns of trays and pulls the requested pallet from its location and brings it to an access point. The operator then picks or replenishes stock and the tray is returned to its home. VLS system offers variable tray sizes and loads, which could be applied in different industries, logistic, as well as office settings. The VLS systems could be customized to fully utilize the height of the facility, even through multiple floors. With the capability of multiple access openings in different floors, the VLS system is able to provide an innovative storage and retrieval solution. The rapid movement of the extractor as well as the integrated warehouse management software system can dramatically increase the efficiency of the picking process. Unlike large ASRS systems, which require a complete overhaul of the warehouse or production line, the Vertical Lift Systems are modularized, which can be easily integrated into the existing system, or to be rolled out in gradually over different phases.
See also
- Actionable information logistics
- Autonomous logistics
- Voice Directed Warehousing
- Warehouse
- Warehouse management system
References
- Frazelle, E. (2001), World-class Warehousing and Material Handling, McGraw-Hill, New York, NY.
External links
Media related to Automated storage and retrieval systems at Wikimedia Commons
AS/RS Providers