Edward Hutchison, Managing Director of BITO Storage Systems, looks at the high-density storage options that allow manufacturers to ensure their production lines keep moving.
Without effective and reliable storage and order picking systems, production and assembly lines will grind to a halt. Just In Time supply of parts, semi-finished products and raw materials to production machines requires flexible and scalable warehouse storage and retrieval systems. They can be either manual or automated.
In factories, space is generally prioritised for manufacturing processes, but sufficient stock will generally be needed in close proximity to production to keep lines flowing. Having denser storage often means parts can be stored closer together to reduce order picking times to provide faster supply to the line.
Determining storage density will depend on factors such as stock profile, investment costs of the racking installation; handling/transport costs per item, which includes the cost of internal transportation and labour; handling capacity measured in picks, ie, the quantity of items retrieved per unit of time; and optimum utilisation of the available headroom and footprint of a warehouse or storage area.
If goods do not have to be retrieved in a specific sequence then drive-in racking is an option to storing and retrieving huge stock volumes. This is particularly relevant for large volumes of the same line item, pressure-sensitive goods and unstable pallet loads, where LIFO (Last In, First Out) works.
An alternative option for optimising space is to install mobile pallet or cantilever racking, where the rack moves to open up a single aisle at the required location. It can improve storage capacity by up to 200 per cent on the same footprint or reduce floor space occupation by 50 per cent. However, pickers must wait for the racks to move and the aisle to open up, which is not ideal for items picked frequently.
For frequent picking, pallet and carton live systems create concentrated storage and pick faces within a given footprint. With live storage, each product line can be presented in a separate flow lane and is directly accessible at the pick face. Cartons or pallets are fed into the flow lane from the rear, and move on rollers to the pick position at the front. Being able to hold sufficient replenishment quantities helps to guarantee constant product availability. In addition to providing compact storage on a small footprint, live systems work on the FIFO (First In First Out) principle, which allows easy control of production batches and sell-by dates. Separate loading and picking aisles increase operator performance and can improve safety as separating replenishment stock carried by lift trucks and pedestrian order picking in different aisles.
This kind of ‘mechanical’ solution often strikes the right balance between investment, density and speed for fast moving parts. Adding simple automation technologies such as pick-to-light and voice picking will further improve accuracy and throughput speed.
Good use of vertical capacity and floor space can be made by using high-rise narrow aisle racking. As a rule, narrow aisle facilities are serviced with man-operated stacker cranes or order picking trucks. This allows picking of smaller unit loads from all racking levels. Guide rails and inductive steering ensure that service vehicles always keep the ideal distance to the installation. Using VNA (Very Narrow Aisle) trucks, will allow aisle widths typically between 1.6 and 2 metres, and the trucks generally operate up to approximately 15 metres high. Going higher means broader trucks and therefore wider aisles. High bay automated warehouses served by stacker cranes can theoretically attain heights in excess of 40 metres, though just over 30 metres is more common. These generally create the highest density solutions.
Finally, it is important to source solutions to support production lines from a supplier that can provide expert advice and the comprehensive range necessary to design and instal an appropriate high density storage solution to meet any challenge a manufacturer might have.
