Moving trends in conveyor systems

For improved productivity and safer working conditions, more companies are looking at overhead conveyor systems to solve their space and access problems.

Australia may be the land of wide open spaces, but when it comes to inside factories and warehouses, space is often hard to come by.

Whether it’s a new manufacturing facility or an existing structure, ramping up production without the appropriate planning can lead to workplace congestion as people and machinery fight for space.

One way to open up the plant floor is to move conveyor operations up and out of the way; creating layout and construction options that are not easily available with ground-level systems.

A number of developments in overhead conveyor design and componentry are seeing the systems being used in a widening number of applications.

Tony Gepp, Sales Director with Luxford, says overhead conveyors (which can be floor or overhead mounted) can offer maximum flexibility and greater efficiency for production.

“For applications which require optimum use of space such as car manufacturing plants, overhead conveyors are used in transporting automotive assemblies through ovens and pre-treatment processes etc.

“Overhead systems also work very well in applications where a lot of people are involved in the process and can be a fantastic solution for continuous processes when they are integrated with other materials handling systems,” he told Man Monthly.

While overhead chain systems are not a new concept, with traditional X Series chain conveyors being around for close to 80 years, Gepp says advances in the materials used for conveyor componentry, particularly in the grade of steel used for the chains, are making them stronger and ideal for heavy manufacturing industries.

“Often, it’s not moving a product that’s the problem, it’s stopping it,” Gepp explains.

“When moving two tonne along at 6m/min for example, this requires a lot of force to hold it.

“While control systems have become more sophisticated with advances in PLC and software providing a range of control capabilities, it’s still important to have a system with a high strength-to-weight ratio to handle it, which is why chain conveyors will always have a place in the production line,” he said.

Keeping it clean

While overhead rivet-less chain conveyors are ideal for high temperature, hazardous and heavy engineering environments, they are not suitable for applications where low noise and cleanliness are paramount.

Conversely, overhead electrified monorail systems (EMS) were developed in order to address these requirements and are quickly replacing less efficient, greasy, unclean material handling systems in a number of manufacturing and assembly plant operations.

Tom Delaney, MD of Webb Australia, says with OHS and environmental issues becoming a key concern for industry, it is incumbent on employers to use as little energy as possible when operating these conveyors.

“EMS conveyors are very clean systems; they don’t require lubrication and are very quiet because you are basically running electric motors.

“These systems can also operate at very low carrier speeds in production areas and up to 100mpm in transportation zones,” Delaney said.

However, EMS’s are expensive in relation to traditional systems; about three times the price of a normal Power and Free (P&F) conveyor and must be kept clean to work efficiently.

Delaney also points out, that another disadvantage of the ‘X’ Series conveyors, is that the chain must return to its origin point after conveying the product.

As an alternative to EMS and traditional chain conveyor systems, Delaney says Swedish company Overhead Conveyor System (OCS) has developed a “Chainless Conveyor Solution”.

“Instead of using chains or electrified energy, the OCS conveyor uses a constantly rotating tube which moves products along from point A to B eternally, eliminating the maintenance and extra cost associated with systems that require a return path,” he told Man Monthly.

The OCS conveyor has been designed to perform the same functions as a traditional P&F system and is just as quiet and clean, and just like an EMS, offers a variety of speeds in different zones, conveyor inclines, lift sections, switches, and start and stop when necessary.

However Delaney advises OCS conveyors are more suited to small-to-medium weight applications, rather than heavy and dirty environments.

“In regards to cost-effectiveness, depending on the application, the OCS product sits between the overhead chain P&F and the electrified monorail as it doesn’t have the return chain nor the expense of an individual drive motor in every single carrier,” Delaney said.

Low volume up high

One industry that has long reaped the benefits of overhead conveyor systems is the food and beverage sector.

Peter Hutchings, MD, FlexLink says for many of the company’s customers, efficient access to packaging and filling machines is essential, and often going overhead is the only viable solution.

However as Hutchings notes, going overhead can also pose some challenges for high mix production environments.

“In a smaller market like Australia, customers often have a variety of product, therefore the guiderails on a conveyor need to be frequently adjusted to suit the load they are moving,” Hutchings explains.

“On a ground level conveyor moving the guiderail in or out is easy, however in an overhead position is a much more complicated process.”

To help mitigate this issue, Hutchings says with the use of AGS (automatic product guiding systems) an electronically controlled system that can be driven by a PLC, guiderails can be quickly reset to the required product size.

“Being able to adjust these automatically is an important consideration when looking at running overhead conveyor systems,” he told Man Monthly.

Hutchings also advises manufacturers to think about the most efficient way to get product up to the conveyor in the shortest distance possible.

“If you have to incline at a very shallow angle, you will still occupy a lot of floor space which makes any benefits of an overhead system redundant,” he said.

The company has designed a number of solutions to overcome this problem, including developing a conveyor chain with cleats or a wedge system which can grip the product and take it up vertically,” he said.