13-11-2012, 05:31 PM
Automated Storage Systems
Automated Storage.pdf (Size: 1.04 MB / Downloads: 298)
Unit Introduction
Storage is an essential function in an automation system. The material storage
system allows materials to be stocked for a specified period of time, before they
are re-introduced, or are introduced for the first time, into the automation system.
The sorts of stored material are related to the product (e.g. raw materials,
purchased parts, work-in-process, finished products, and scrap and rework), the
process (e.g. process refuse, such as process waste products; and tooling), and
the overall support functions in the factory (e.g. maintenance spare parts, office
supplies, and plant records). Each of these material types is typically stored
under different conditions and controls.
END KEYPOINT
In this unit storage equipment is described, alongside appropriate methods in
both conventional and automated storage systems. Storage system performance
and location strategies examine the operating characteristics associated with
storage systems, and where best to place and organise them in the plant layout.
Conventional storage methods and equipment turns to an investigation of how
storage is regularly accomplished, and the pieces of equipment that is used to
achieve storage aims. Automated storage systems, which reduce or eliminate
human intervention in the system, are subsequently described. This is followed
by an engineering analysis of storage systems, in their various guises. A case
study completes the material of the unit, followed by the review of the unit and
the self-assessment questions and answers.
Storage Systems
Storage systems are used to store materials related to the product (e.g. raw
materials, purchased parts, work-in-process, finished products, and scrap and
rework), the process (e.g. process refuse, such as process waste products; and
tooling), and the overall support functions in the factory (e.g. maintenance spare
parts, office supplies, and plant records). Storage systems can be classified into
conventional storage systems and automated storage systems (Figure 9.1).
Automated Storage/Retrieval Systems
An automated storage/retrieval system (AS/RS) is a storage system that
performs storage and retrieval operations with speed and accuracy under a
defined degree of automation. Different levels of automation may be applied. At
one extreme, the AS/RS is completely automated. This can include a full
compliment of totally automated, computer-controlled storage functions that are
integrated into overall factory or warehouse operations. At the other extreme it
may use human workers to control equipment and perform storage/retrieval
transactions. Using modular components, available from AS/RS vendors, the
AS/RS system is custom-designed to fit the requirements of the plant in which it
is installed.
END KEYPOINT
The basic equipment of the AS/RS include a rack structure used for storing
loads, plus a storage/retrieval (S/R) mechanism with three dimensions of motion
(x, y, z). Additionally, the AS/RS maintains one or more storage aisles that are
serviced by the S/R mechanism. The S/R mechanism is used to deliver materials
to the storage racks and to retrieve materials from the racks. Each aisle has an
input/output station where storage deliveries are transferred into the system, or
out-of the system; these stations are known as pickup-and-deposit (P&D)
stations. P&D stations may be manually operated or connected to an automated
transport system, such as a conveyor or an AGVS (see Figure 9.2).