chaz4Still looked upon as costly, noisy, power hungry, contaminatory and prone to chain stretch, overhead conveyors suffer a poor, undeserved image. The fact is that design changes have designed out some of industry’s concerns. A good example is the chainless rotating tube conveyor, which is almost silent and much cleaner than chain conveyors. Users say that they far outlast chain-driven conveyors but they are restricted to handling loads no more than 0.5 tonne per trolley.

Properly chosen, the overhead conveyors are, perhaps, the most productive of all conveyor types and can prove far more cost-effective than alternative handling means like forklifts, AGVs and trolleys.

Compared with ground-based conveyors they may be 8-13% more costly to buy and maintenance could be more problematic, but as with any materials handling investment it is the life cycle costs that should dominate.

Such is overhead conveyors’ flexibility today that they can buffer, divert, raise or lower, load or offload, select specific items, sort and report on their own state of function and the positioning of items it has transported. They can automatically interface with other handling devices like AGVs, robots and lifts as well as communicate with warehouse management systems (WMS).

As with any automated materials handling systems, specifiers should ask if the system has enough designed-in flexibility and adaptability to meet changing future requirements. It is important that the control software has the functionality to integrate smoothly with current IT systems and that the supplier is committed to “whole life” care in terms of service, maintenance and upgrades. Many buyers still have hazy ideas about their volume throughputs, so it is crucial to validate these throughputs while making allowance for any future variations in product sizes.

There are many reasons for going aerial with conveyors, among them being productivity gains, safety, damage levels, build quality of conveyed products, space savings, reduced stocks and work in process and capacity gains. Achieving a combination of these factors can often yield an investment payback in under two years.

A look at any production process, for example, often shows that 55-60% of the time is spent by personnel moving, finding and picking items. Materials lie on the floor by assembly stations, taking up valuable space and posing hazard risks. These materials are often delivered by forklifts, posing yet more safety risks and there could even be a higher fire risk if workers have to unwrap packaging and store it temporarily close by. All of that can be eliminated by overhead conveyors.

The improved ergonomics, and its impact on productivity, conferred by going overhead should also not be overlooked. Aerial conveyors allow assemblers to rotate, raise and lower loads to an ergonomic working position.

The ultimate achievement in overhead conveyor versatility, perhaps, is when they become factories in the sky. This occurs when the moving trolley is large and robust enough to act as an assembly station, an advantage exploited by many car makers, in particular. But the nature of the conveyed product can also favour overhead conveyors. If, as with sanitary ware, the goods have high centres of gravity outside the norm, then transport by forklift or even flatbed conveyors could cause high damage levels. One sanitary ware producer also found that taking the overhead route would save £0.5m compared with using forklifts instead.

Warehouse & Logistics News

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