Storage Systems: Live Storage System

This design of racking system allows the pallet load to be fed into higher end, and to be retrieved from the lower end (so called as pallets move in the racking). After pallets are positioned at the end of the racking by, for example, a fork-lift truck, the movement in the racking is facilitated by having a structure that permits movement horizontally down the racking by incorporating rollers on which the pallets slides. The movement can be with gravity with, say, a 4% slope, or the pallets can be moved by powered rollers. The choice depends on individual company requirements and on safety requirements at a maximum speed of 0.3 metre per second. Live racking can be used to 'automatically' position pallets on a First-In-First-Out basis and also positon pallets in another part of the warehouse.

Advantages

-Floor storage space utilisation of up to 70%
-Saves cost (e.g. manpower)
-Increase picking productivity
-High density storage

-No power source needed

Disadvantages

-Products cannot be kept long
-High expensive set-up

Applications

Suitable for high throughput per line item and products that are of uniform size and shape.

The video below shows how the live storage operates:

The following case study illustrates usage of live racking:

CASE STUDY: LIVE RACKING AT BMW

Pallet live, carton live and mobile line side live-storage are all features of the investment that will help the plant to achieve a 39 second cycle time for engines to support the BMW group’s production network. The production of the engine requires a supply of 400000 varied components to assembly lines everyday.

Hams Halls is a pristine, state-of-the-art manufacturing and assembly facility for BMW’s 1.61.8 and 2 litre, four-cylinder ‘Valuetronic’ petrol engines, with highly automated operations that adhere to the principles of lean, JIT production.

‘Our storage and component delivery systems have to support a truly 21st- century enterprise,’ say Hughes of BMW, ‘a floor plan was devised for our “small container supermarket” comprising nine aisles of pallet live storage, providing 110 pallet pick locations, each with a reserve pallet location and a single tier carton live storage, above the empty pallet return system services each bay for efficient pallet return, safety and minimal congestion at the pick face.’

The feed sides face on to wide aisles, replenished by electric forklift trucks operating from a conveyor feed from an auto store, while special commissioning vehicles operate in narrow aisles fronting the pick face.

‘The components within the bays are positioned in such a way as to allow the components to be picked sequentially, exactly in the order that they will be required at the production line. There is no need for pick vehicles to back up or travel along the feed aisles.’ says Hughes.

Inside the main assembly hall, engine sub-assemblies are delivered to work stations by AGV’s (automated guided vehicles). At these stations, line side live units are an integral part of a pick-to-light system. Ergonomics are a key consideration and the minimal motion required of operators at each station is immediately noticeable.

‘The main live storage installation services our slow moving components which on average draws between one and two boxes of a particular part number, per hour’ explains Hughes. ‘Fast moving components are delivered to the line by pallet-load.’

A consideration when specifying the project was that the storage system could keep pace with increasing complexity as various engine derivatives are introduced into the build schedule. The static carton live bays will eventually take many channels each and there is capacity to put at least 300 part numbers through the system, which should satisfy long-term projections for the plant.

Source: Industrial Handling and Storage, October/November 2001.