Optimising Pallet Flow Performance
23 Mar 2017
Some warehouses store goods that have a high turnover, so fast access is needed. Others store perishable goods that must be moved on a FIFO basis (First In, First Out) to ensure that the oldest goods go out of the warehouse first, obeying stock rotation rules. In both of these cases, the traditional warehouse configuration of pallet racks separated by aisles, with forklifts picking items, is inefficient.
With pallet flow storage, this model is turned on its head. Instead of the forklift going to the pallet, the pallet comes to the forklift.
Rolling Pallets Using Gravity
This is achieved by arranging the plastic pallets in storage lanes and allowing them to roll gently forward towards the forklift through the use of sloping wheel conveyors underneath them. Pallets can travel on full-width rollers or on twin-tracks. This configuration uses at least 60% less space than traditional pallet racking because it only needs two aisles for forklift trucks – one at the loading end and one at the retrieval end.
Because of the increased density and efficient use of warehouse space, the system can be suitable for temperature-controlled foods, such as frozen or chilled goods. The cost of storing these types of item in a cooled warehouse is far higher than the cost of running an ambient temperature warehouse. The extra efficiency in storage and operating performance can make the cost-benefit analysis work better by offsetting the costs of temperature control against the extra storage and lower handling costs in the warehouse.
Many flow systems have different types of pallet in each lane. Obviously, the set-up has to match the requirements of the plastic pallet sizes and load requirements. Pallet quality is important because these systems are based on standardisation and make assumptions about the quality of pallets in the system. Similarly, the reliability of the storage system is dependent on both the brakes and the pallet flow rails.
Systems with insufficient flow rails won’t support heavier pallets properly. The quality of the gears is important, and all-steel gears tend to deliver higher performance and longer life, without the need for springs or any external power source.
Health and Safety
Uncontrolled movement of the plastic pallets is not possible because the track has brake rollers and an automatic braking function. And to ensure the safety of employees working at the retrieval face, the pallets are brought to a safe stop by an end stop and load separator. The separator holds back the queue of pallets until the bottom one has been safely taken out by the forklift driver.
Because the forklifts are not going up and down stacked aisles, there is less scope for accidents due to poor stacking. In addition, the risk of rack collapse is greatly reduced because the operators have less chance to back the forklift into a loaded rack, which might collapse, with the consequent domino collapse effect across the warehouse that can occur in the worst cases.
And because forklift movements are themselves a health and safety risk, the reduced movements with pallet flow storage automatically contribute to a reduced accident risk.
So for performance, a fast turnaround and enhanced safety, a flow system is hard to beat.