Dynamic approach to parts storage

Neil Hodgkinson, contract manufacturing engineer at Getrag Ford Transmissions headed the project to improve parts storage as part of a wider lean logistics project to centralise logistics operations within the plant. He says: "The new Interroll Pallet Flow system has been located closer to our production area and has provided compact, space saving cubic storage, enabling identical products to be grouped in the same lane and bays. This in turn simplifies location and order picking of parts to support production of some 1600 to 2000 gearboxes daily.”

The challenge for Interroll came in handling a mix of both plastic and wooden pallets of various sizes, with different base configurations and weights. This ranged from Euro pallets 800 x 1200mm, to UK pallets 1000 x 1200mm and plastic pallets with bases featuring three runners through to those designed with nine raised plastic moulded feet – all carrying weights from 600 to 1000kg. It was essential for Interroll to accurately identify the correct dynamic modular specifications to provide smooth, controlled and even pallet movement.

A selection of pallets were forwarded to the Interroll Centre of Excellence for Dynamic Storage in La Roche sur Yon in France. Interroll carried out trials on roller test tracks under controlled conditions, at an ambient temperature, whilst conveying the customer’s individual pallet types and loads. Tests took into account the gradient of the slope, the controlled speed of descent, online separation and restart of standing pallet loads.

The final test solution resulted in each lane being designed with 60mm diameter rollers at a 78mm pitch and Interroll’s latest Safety Separator incorporating a Time Plus function, which ensures the safety of the operators and facilitates ease of operation. On lifting the first pallet to remove it from the order picking face, there is a time delay before the separation device releases the next pallet in line. This gives the forklift driver time to unload the pallet safely before the second pallet is released.

Interroll Speed Controllers keep the pallet at 0.3m/s constant speed whatever the pallet weight. To control the speed of all the different pallets, a special configuration had to be adopted for plastic pallets. Each roller was knurled in three strategic positions across the width to provide a positive surface grip and control the speed until the end stop. This worked well with all pallet materials, but as the knurling could shave the surface of wooden pallets, scheduled maintenance and cleaning of the systems was recommended to the customer.

The experience gained through working with Interroll during testing and evolving a Dynamic Storage solution motivated Getrag Ford Transmissions to entrust Interroll to work closely with Planned Storage Systems, which was appointed to supply the rack support structure, finished to the customer’s specified colours.

All the FIFO lanes from Interroll were fitted with rollers 1250mm wide to future proof the system, should at any stage 1200mm x 1200mm wooden pallets be introduced to the system. Within weeks of installation, this has already proved a forward thinking approach as wooden pallet sizes are now appearing in the supply chain.

Within the project specification, the load bearing requirements were included for supporting the new dynamic storage racking and as the designated floor area was tiled, Getrag Ford involved consulting engineers PSA Design to undertake a structural survey of the area and take core samples for examination. The core crush tests proved the tiled area to be a sixth of the strength of the solid area and as a result of their recommendations, foot loading plates were used to spread the load of each rack leg.

Neil Hodgkinson says: "At the beginning of this project, the concept of pallet flow storage was appealing but offered a number of challenges and needed expert support. With many variants in pallet construction – size, materials and weights – we went to Interroll Centre of Excellence for Dynamic Storage in France with many unanswered questions and came back with a solution.

"The installation was completed to our satisfaction and feedback from our logistics team is very encouraging.”