Integration is key
September 1st 2007

Developments in almost every area of engineering are delivering big benefits for the food industry, as Ian Dickson of Bosch Rexroth explains. He believes, however, that the real key to maximising these benefits is not innovation alone, but innovation combined with integration

Smarter, safer, more reliable, more flexible and more cost effective – these are the constant demands that users in the food industry make of their machines and systems. And there's no doubt that progress in many areas of engineering is making it possible to address these demands more effectively than ever before.

The best suppliers are not only making full use of their own expertise to drive this progress, but are also increasingly collaborating with organisations such as the well-known Fraunhofer Institute to ensure that their products meet the highest standards, and that they are properly certified for use in critical applications.

Let's take a look at a few examples of the progress that is being achieved in the key areas of pneumatics, materials handling, automation and drives.

In pneumatics a particularly significant development has been the emergence of hygienic components, such as cleanprofile valves and cylinders which are free from dirt traps, and which are designed to operate reliably in washdown environments. In fact, corrosion-proof pneumatic valves are available with ingress protection ratings as high as IP69K. These products can be mounted directly on machines without the need for protective enclosures. The valves are, therefore, closer to the actuators they control, which allows operating speeds to be increased.

In materials handling, some really innovative technologies are making their presence felt, such as non-contact transfer devices which harness the Bernoulli effect to lift and transport small items without them ever touching the transfer device itself. Although not yet suitable for use in the most aggressive washdown environments, these new devices provide convenient solutions for the problems of moving irregularly shaped, porous or delicate items in a variety of food-related applications.

Having an even greater impact in materials handling is the growing deployment of robots, which are now starting to offer an efficient, cost-effective alternative in a range of tasks which, until recently, could only be performed manually. The latest Cartesian robots are particularly versatile, and are being used for functions such packing food products into shipping cartons, and also palletising cartons ready for despatch.

These new robots are not only versatile but also easy to program and use. Some robots can, for example, easily be configured on-line, eliminating much of the design effort previously necessary.

Typically, these versatile new robots are supplied as axes that are ready-built with pre-configured drives.

This approach translates into shorter engineering and assembly times, as well as significantly reducing the technical and financial risks associated with the project.

Software for use with the robots is now also being offered in a convenient preconfigured form, with leading suppliers offering libraries of tested and proved function blocks for use with their products.

Covering essential functions for common applications such as palletising, these blocks mean that the system integrator doesn't have to develop the program code from scratch, resulting in even more reductions in time, cost and risk.

Sophisticated automation systems, often based on programmable controllers (PLCs) provide the foundation that underpins the functionality of all modern machines and systems. Here, once again, the hallmark of the latest offerings is versatility combined with ease of use. One of the most significant trends, however, is the adoption of open technologies.

On one level, openness makes it easy for automation products from different manufacturers to talk to each other, freeing users from ties to their past suppliers, and allowing them to mix-and-match products to get the best possible balance between performance and cost.

On another level, openness in automation removes the need for users to start the learning curve afresh each time they buy a new system. As an example, the widespread adoption of IEC61131- compliant programming languages for PLCs means that programming skills learned in relation to a product from one manufacturer are equally applicable to PLCs from other suppliers.

In most cases, the muscle needed in food processing and handling equipment is provided by drives, and their performance is often the factor that determines the overall performance of the system. Though simple fixed speed drives still have their uses, modern machinery makes extensive user of inverter and servo drives.

While there is a little overlap in applications between these, the essential difference is that inverter drives work with low-cost induction motors and give very effective control over the motor speed, while servo drives work with servomotors and give accurate control over the angular position of the motor shaft, as well as its speed. Inverter drives are undoubtedly indispensable in food processing plant, but it's the servo drives that are currently yielding the most important advances.

Of particular interest is shaftless technology where, instead of being driven from a common shaft via gears, belts and chains, the various functions of a machine are each powered by their own individual servomotor. The synchronisation of the machine functions is then achieved electronically using an arrangement sometimes referred to as a virtual axis.

The benefits of shaftless technology are enormous. It eliminates the costly gears, belts and chains, it allows more compact machines to be produced because these mechanical drive components no longer have to be accommodated, and it greatly reduces maintenance requirements. It makes the machines simpler and easier to build, and it makes them much more flexible. Modifications in a shaftless machine usually mean only a few inexpensive program changes, whereas in a traditional machine, they invariably mean a costly mechanical rebuild.

It's worth noting that shaftless technology is not limited to applications with new equipment. In many cases, it provides a very convenient way of upgrading existing plant by replacing the original shaft-drive arrangement with servos. In such applications the latest integrated servo drives, which have the drive electronics mounted directly on the servomotor, are particularly useful, as they reduce the amount of wiring needed and eliminate the need to find extra space in the control panel for the drive units.

Clearly, the developments in specific areas of technology potentially make many benefits available.

But there is another hurdle to cross before this potential can be translated into reality – integration. There's little to be gained by having the latest and most sophisticated products in every area of a machine or system if they can't all be made to work together harmoniously.

This is no theoretical problem. There can be few major specifiers or end users who, over the years, have not experienced problems when equipment from different suppliers simply refused to co-operate.

Even worse, when this happens, none of the suppliers is likely to accept responsibility and the result is all too often an impasse where the end user is the loser.

The best way of avoiding these problems is to choose a supplier that can offer all of the key technologies needed in a project. Compatibility will then be guaranteed and there can never be any issues over divided responsibilities. With the right supplier, there can also be additional benefits.

For example, some companies, such as Bosch Rexroth, offer software tools which make it easy to integrate their mechanical, electrical and pneumatic components in a design. Not only do these tools save time, they also make it fast and easy for designers to evaluate different options and ultimately, therefore, produce a better final product.

For users in the food industry to get the best from modern engineering technologies, there's a further factor they must consider – the size of their supplier.

Put simply, smaller companies are unlikely to have the breadth of product range needed to act as true single-source suppliers, and they are also unlikely have the resources needed to back the food industry's larger projects. Stability is another important concern. A large supplier is likely to be around to provide support throughout the life of the plant, whether it be five, ten or even twenty years. The same may not be true of smaller companies.

Finally, with the food industry becoming increasingly global, the question of worldwide support becomes an issue. If you are an OEM or food multinational, you may possibly be satisfied with the support you get in the UK from a particular company, but what will happen if your machine or system is moved to an overseas location? Will responsive local support still be available?

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