Automated storage and retrieval systems have had dramatic impacts in reducing picking times and increasing warehouse efficiency for particular operations. However, technology has restricted the application of automated systems.
Latest improvements in the systems are changing that and now more companies are adopting them. Automated systems have always suited those companies which operate high storage densities and those whose goods include small or expensive items. In the past, they have been ideal for operations with limited warehouse space or those where security is a high priority. Now, some new improvements in vertical lift technology may open the door for others to employ the technology throughout their own operations.
Graham Boner of Diamond Phoenix says that in the past, the design limitations inherent in vertical lift storage devices have restricted their use to specific applications. However, he says significant advances have been made over the last few years which have made the technology more viable for a greater range of operations.
“The nature of the traditional straight and curved track guidance systems in vertical carousels has restricted both carrier width and depth, limiting its use to markets which handle small, lightweight parts.”
With the introduction of dual-chain guidance systems which eliminate the track system and allow carriers to be up to 55 inches deep (which is 29 inches more than the previous restriction) the increase in carrier size and capacity now allows the carousel to store products that are bigger and heavier. Boner says the vertical carousel can no longer be considered suitable for small, light parts only.
Vertical carousels have had problems in the past with loads that are not evenly balanced. If too much weight exists on one side of the unit, or the carousel is not evenly balanced, it makes it difficult for the drive system to power the carriers around the curves at the top and bottom of the unit.
Previously, when these situations arose, alarms were triggered in the unit to notify the user. This required the user to reconfigure carrier layouts constantly, ensuring that the unit stayed within the 20 – 25 per cent maximum tolerance for out-of-balance carriers.
“If the out-of-balance condition is not corrected early enough, additional wear occurs which will shorten the life cycle of the machine.”
Recent innovations in dual chain guidance and dual-drive motors have now solved this problem, says Boner. Vertical lift module technology has also seen substantial advances in recent years. These improvements include dynamic storage as opposed to fixed storage positions, integrated weighing scales to prevent overloading of trays and the unit, multiple height delivery locations to enhance ergonomic picking positions, and even user profile systems to provide friendly and easy to operate user interfaces. He says the greatest development in this technology has been the introduction of the multi-bay vertical lift module.
Previous vertical lift module technology was only available in a single-bay design. Market statistics show that the average application requires an average of more than two units per installation.
The multi-bay vertical lift module supplies a unit that has two, three or four bays of storage with a common controls and lifting package, the operator has access to the entire inventory from one central picking location. Single-bay technology in the same application would require multiple units, all with their own controls and lifting devices.
This significantly reduces access to the entire inventory of parts and forces the operator to visit more than one unit to gather all of the required items. This in turn decreases overall productivity, not to mention that operators now have three to four times the number of controls and lift packages to maintain.
Multi-bay vertical lift module technology also allows more than one delivery window to be active at any given time. Multiple operators can be picking from the unit at one time, each having access to all parts across all bays of storage. Single-bay technology would force each user to wait for the other operator to complete his transaction if his next required part was located in that same unit. One user may also work from both windows creating a queueing system at each window until the entire order has been picked, again greatly increasing productivity.
This simultaneous unit operation not only allows multiple operators to pick at the same time, but the unit can also be restocked or parts assigned to the system while the picking operation is still in process. This is the only point of use technology that allows a replenishment operation to occur during a picking operation.
Keith Wootton of The Live Storage Company says some companies invest in the latest storage and retrieval technology without fully understanding what it will offer their operations. Sometimes a simpler system is better suited to the needs of an operation.
“Many companies invest in advanced solutions to their storage and retrieval requirements when a simpler and less expensive alternative can be just as effective. By converting static faces into live picking many companies can make a significant improvement to efficiency without the expense and disruption of introducing an automated system.”
Nick Tyler managing director of The Live Storage Company says live picking can fit the bill for companies which do not want to spend a lot on an expensive automated system.
“Warehouse managers faced with the challenge of increasing storage capacity or order picking performance are often tempted by big-budget solutions that involve automation, computerisation and complexity.”
Tyler argues that gravity fed live roller tracking is one area where gains are possible which require only a modest outlay compared to an automated system. “Keeping it simple and looking to improve basic tasks can be just as productive and much less expensive.”
Gravity fed live storage replaces static shelving with a sloped roller bed with items replenished from the back and rolling to a pick face. Tyler argues that this continuous flow of goods “makes live storage ideal where first-in, first-out picking is required” for example with limited life items such as food or pharmaceuticals. The system also eliminates the dead picking zones, where some goods are too high to reach without materials handling equipment.
BMW uses twelve Hänel Lean-Lifts at its UK parts distribution centre in Bracknell. They operate simultaneously to retrieve automotive parts where they are send out to dealers around the UK. Parts are brought direct to the user in seconds and are picked using a pick-to-light system. Mayflex Electronics, a Birmingham-based electrical parts distributor, has been using six Lean-Lifts since 2004. Logistics manager Jez Warne says: “There is no doubt this innovative way of working in the warehouse is benefiting our customers. The speed at which goods are picked and replenished using the Lean-Lifts ensures that both efficiency and accuracy are substantially enhanced”.
The John Lewis Partnership chose Knapp for the automated storage and retrieval system at the £45m, 650,000 sq ft warehouse it is building at Magna Park in Milton Keynes.
Knapp is supplying a fully automated logistics system including its Order Storage and Retrieval System. Construction started in December 2006, and will be completed in the first half of 2009. Knapp says the £18m contract involved two years of extensive planning before work began on the project. The new facility plays a key part in John Lewis’ growth plans and will support the opening of ten new shops in the next ten years, and expects to open ten more after that.
The site, which is at junction 13 on the M1, will mainly manage smaller items which are currently handled at the Stevenage site. Once the new facility is operational, the Stevenage warehouse will be reconfigured to handle larger goods.
Patrick Lewis, supply chain director for John Lewis, says: “To win in our market, we need to improve our service continually. This new development gives us the space we need to increase the scale of our business, and allows us to provide better service to our shops and customers, at a lower cost.”
The project is Knapp’s largest ever single contract and required a six week data analysis with a simulated system, to ensure that Knapp’s system was the right one for the job. The Order Storage and Retrieval System works on a goods-to-man principle with pick-to-light and put-to-light technology and can give up to 1,000 picks per man-hour.
Whoever said a vending machine needed to contain food or annoying plastic children’s toys? BuckHickman InOne has developed a vending machine for industrial stock management using Cribmaster inventory management software to control and record stock usage.
The most basic security option controls access to a cabinet or cabinet drawer using an electronic lock controlled by Cribmaster. Higher security options restrict users to single product access, either through the controlled opening of a drawer or single door, or by using a helix system where the item drops into a bucket like a conventional vending machine.
An individual can gain access by using a swipe card or by typing in his PIN on a touch screen. Next the user enters information relating to his cost centre, project or works order, before selecting the item he requires using the screen. This then either releases an electronic lock or operates the helix to permit access to the item.
Standard industrial storage units can be used or the intelligent locking controller and Cribmaster software can be retrofitted onto existing cabinets.
The vending systems are programmed so that staff have either full or limited access to stock. Line managers use a special interface to programme new user’s access in seconds or to change access permissions. The software can also manage the use of shared tooling or serialised items by reporting on who is using the stock and whether or not an item has been returned to the cabinet or drawer.
When an item is removed, the software updates the inventory remaining. The software can also reorder stock online using either a direct connection to BuckHickman InOne’s system or through an existing ERP system. Alternatively the stock can be recorded and replenished on a regular cycle. If items are running dangerously low then an e-mail alert is issued via email or SMS.
Cribmaster can control any combination of automatic locks or vending systems. It is also adaptable and can be expanded to meet future needs. More than 170 standard reports are available using Cribmaster. These report stock usage at several different levels, for example by individual user, product, departments, production cell or job number. Cribmaster is compatible with Windows 95/98/2000/XP and NT.
Kardex’s Sentinel vertical carousel uses the latest technology to speed up the storage and retrieval process. The Sentinel is based on Kardex’s Industriever range and uses up to 26 carriers that automatically rotate to deliver goods directly to the operator in the fastest possible time. Automatic sliding doors positioned across the picking face, synchronise with rotating shelves to offer access only to the exact component or storage bin requested, eliminating picking errors.
Kardex says another benefit of the machine is that the internal shelves can be configured to a variety of different heights and depths.
Clive Williams, UK sales manager at Kardex says: “Industrial suppliers use them to hold and track consignment stocks at customer premises.
“Manufacturers have them to keep better track of consumable use on the shop floor; while companies in the pharmaceutical sector use them to maintain highly-accurate inventory records during drug development and production.”