Leuze Laser Scanner Ensures Tote Boxes Are Empty

Leuze Electronic's ROD 4 Laser Area Scanners have been deployed throughout the large distribution warehouses of JD WIlliams for applications ranging from data-transmission to barcode scanning. The ROD 4 scanners instantly made an impact on the organisation's ability to track potentially lost items and re-route them for entry into the sort path. 'The scanners have reduced the number of items that need to be traced manually to around one per cent, compared with 10 per cent prior to fitting them,' said Ron Rutter, maintenance team leader.

Leuze optical sensing technology is central to the overall efficiency of the JD Williams warehouse, with applications ranging from data-transmission in the high-bay warehouse, barcode scanning for stock verification from suppliers and location allocation. The Ethernet-ready ROD 4 scanner was brought into the warehouse to eliminate a situation where tote bins that did not empty their entire picked loads would still be free to automatically be sent back to take up position in a new order-pick cycle.

Only later would an alert be raised, items arriving at the final packaging station not correlating with the actual pick list. It meant a manual search to locate bins with the items. Items that occasionally remain in the bin tend to be slim packs such as ladies tights, the reason may be an ill-fitting adhesive label attaching the pack to the side of the bin. Two Leuze ROD 4 optical scanners are included in the tote-bin return path immediately after the discharge point. Tote bins are tilted through 160deg, emptying their contents for final transfer to the packing stations.

After righting they are conveyed on one of two lines back into the order pick process, but not before passing beneath a ROD 4 scanner. These can be programmed to sweep a 2D arc up to 190deg, permitting the width, contour and position of an object to be detected. At JD Wiliams both scanners are connected to a S7 300 PLC and operator panel. The system shows number of boxes scanned and errors found, this is then integrated into the order picking control system. The scanners sweep the internal dimensions of every tote bin, any foreign object is automatically detected and the bin is sidelined for the item to be removed and returned to final packing stations.

Since the introduction of Leuze Electronic's ROD 4 scanner the potential for lost items has almost been eliminated. This is thanks to the accuracy and adjustability of the scanner. JD Williams, based in Oldham, handles in excess of 150,000 items per day. The nature of this home delivery service relies on a highly efficient handling system that can track new orders from pick to despatch as well as a returns department where items are inspected and then only returned into the pick bays or bulk store. The high operational efficiency calls for reliable sensing capability, automating as many processes as possible.

To achieve this more than 300 Leuze Electronic scanners and barcode readers are deployed throughout this distribution centre. As boxed items arrive from suppliers they feed through an enclosed twin-roller conveyor delivery system. Leuze BCL 80 barcode scanners precisely read the attached barcode to identify content and ensure it correlates with expected delivery. Each carton is held on a slim tray, which also carries barcoded data. During this initial stage the boxed content and tray are married for onward tracking and location placement. Fast-moving items are sent to bulk storage racks for easy pick while the lion's share of items are held in a 32-aisle, high-bay warehouse with 400,000 individual store locations.

Information to each automated crane is sent using Leuze optical data transmission systems such as the DDLS 200. Using Leuze Electronic's optical data transmission technology in warehouses is said to reduce maintenance due to contact-free communications, eliminate hard-wiring to cab-mounted controls as well as lower interference susceptibility to noise from light sources. These latest developments are network ready with inbuilt Profibus connectivity and offer a 500m range with data transfer rates up to 2Mbits/s. A feature of the design enables a single person to install and align the units, hitherto not practical with other designs.

This DDLS 200 installation is typical of the applications where this unit excels, the transfer of data to and from stacker cranes operating in automated storage and retrieval (ASR) applications. One of the most significant benefits of these devices over alternative systems such as bus bar systems is that they negate problems associated with wear and tear caused by continual crane travel, thus eliminating downtime and costly repairs, according to Leuze. Each crane can pick and hold cartons from two different locations.

To ensure complete control and identification, two Leuze BCL 40 barcode readers are mounted alongside the handling device to log what has been collected. At discharge the trays/boxes are transferred by roller conveyor to a number of locations such as bulk store, straight to final despatch or sent to replenish the many manual pick locations. In using the Leuze Electronic BCL 40, JD Williams have units designed to read codes close-up. From a distance as small as 10mm, the scanning field covers a beam angle of 70mm, which widens with increasing distance. The BCL 40 is a compact unit, complete with integrated decoder measuring just 43mm in depth, 120mm high and 90mm wide.

Once trays and cartons leave the high bay or during their route direct to pick face, the transfer cycles are controlled via strategically positioned BCL 40 barcode readers, tracking cartons by reading the code on the slim carrier tray. Throughout the movement of cartons, each is held on a slim tray, which is used to identify and track movement. The trays have identifying barcodes positioned on the very slim edge of the plastic tray and this runs parallel to the conveyor's rollers. The potential for incorrect reading and subsequent tracking of a tray and its load was tremendous due to code location.

The chosen barcode reader must have the technological capability of being mounted sufficiently high above the conveyor so as not to inhibit carton flow yet have a powerful focal length to accurately read the ID code, which is virtually out of sight on the transport tray. For this application, Fulfilment Logistics turned to the capabilities of the Leuze BCL 80 series. The BCL 80 offers extra-long scanning distances up to 2,400mm and a wide depth of focus enabling it to quickly and accurately read the ID labels on the narrow trays.

It is supplied as standard with a capacity for 600 scans/s, although versions are available to accommodate applications with requirements of between 400 to 800 scans/s. The BCL 80 barcode reader also has the ability to detect and signal deterioration in label quality. Long-term operation of label printers and use of soiled or damaged labels means impaired contrast between the label and barcode. The ability to recognise such situations allows preventative action to be taken, averting potential costly remedial action such as re-labelling.

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