Keep those car parts rolling

Who says conveyors aren’t high-tech? Mercedes-Benz has recently installed a super-smart one incorporating 209 photocells and 42 barcode scanners.

Since 1985, Mercedes-Benz has supplied spare parts to its UK dealers from a 43,000m2 warehouse beside its UK head office at Milton Keynes, Buckinghamshire.

But growth in sales, plus the addition of the Chrysler range to the group, has put increasing pressure on the site.

Hence a major investment to create eight new ‘European Logistics Centres’, of which Milton Keynes is one.

The storage and picking procedures at the site have been transformed. The original system involved all incoming deliveries and out-going items for dealers being moved around the warehouse by staff using trolleys. Access to the two upper storage areas was provided by staircases and lifts, with staff using the stairs and goods going in the lifts. At peak times the lifts simply could not accommodate all the trolleys that needed to be moved between the three levels.

To design and install a new system, DaimlerChrysler chose the German company Gebhardt Fördertechnik GmbH, which had already completed similar projects at new ELCs in Madrid and Rome, together with its Nottingham-based UK representative, European Conveyor Systems.

The new installation would cut walking distance covered by staff by half.

As part of the conveyor system, ECS installed Gebhardt’s own Materials Flow System (MFS) linked to reflecting bar codes to control the routing of parts and provide real-time graphic information to enable faults to be identified. The MFS was integrated with the existing Microlise OPUS software already in use at Milton Keynes, which generates orders from dealers and provides real-time management information.

How it works

Stock arrives at Milton Keynes daily from Germany by road in outer cases or on stillages, which are unpacked in a goods-in area. Each product carries a number in analogue and barcode form, which an operator reads with an RF scanner linked to the MFS. A printer at one of eight workstations in this area then produces a binning label, which includes the destination within the racking.

The products are carried in polypropylene tote boxes, suitable for nesting or stacking, supplied by Schaeffer Systems, who also revised the racking. Each tote box has a number that is input into the computer in the goods-in area, together with the numbers of the products in it. The conveyor then routes the box to the correct destination in the storage area.

The three levels of racking in the warehouse each have five workstations which act as a base for the staff replenishing and picking stock. Each level has about 30,000 separate bins. Tote boxes with goods for replenishment arrive at the workstations. Staff take them on trolleys to the correct bins, as indicated by a number on each item.

When they have been emptied, tote bins are put on a return conveyor which takes them back to a stacking machine where they are held until called off again. Before they are stacked, a photocell checks they are empty and the right way round for stacking.

Parts picking is generated by orders from dealers fed into the OPUS computer system, which allocates items required to the appropriate workstation within the ‘live storage’ areas. Picking tickets output by the workstation computer are sorted automatically into dispatch routes and in location sequence.

When a tote is full, staff scan the picking ticket and the barcode on the tote box before putting it on to the conveyor. The tote is then automatically routed to its destination in the dispatch area, where roll cages marked with each dealer’s number are filled. Roll cages have replaced stillages, being easier for dealers to handle via tailgate lift on the delivery vehicle.

As a final check that the roll cages are being delivered to the correct destination, a barcode on each one is scanned before being loaded on to a lorry.

The cages are taken overnight to a number of sub-bases throughout the UK. At these, they are trans-shipped on to the vehicles that make the deliveries to dealers every morning, Tuesday to Saturday.