A large part of Europe’s general manufacturing industry has spent the last three decades investing in automation in the never-ending search for greater efficiency and higher quality at lower cost. For much of that time, the food industry has however been lagging behind other sectors in the take-up of automation. Growing pressure on profit margins, difficulties in recruiting and retaining sufficient skilled labour, health and safety requirements, technological progress and other factors have now prompted some food manufacturers to look more carefully at automated solutions. With automated packaging and palletising operations now a common sight in many plants, attention is turning towards more complex and demanding tasks further upstream in the production process. With research constantly improving the technology, how long will it be before robots take over all but the most skilled jobs in our food factories?
Simple mechanical automation of industrial production lines is nothing new — the engineering and control technology needed to directly replace human operators was first developed back in the 1970s. Some manufacturing sectors, notably the car industry, embraced the new technology almost immediately. Anyone who saw the famous Fiat “hand built by robots” television ad first shown in 1979 will remember how futuristic an assembly line manned entirely by robots seemed at the time. The same ad looks unremarkable today, such has been the advance in automation technology, but the reasons for considering an automated manufacturing process remain much the same, whether the end product is a car or a frozen pizza.
The pros and cons of automation
Many of the tasks involved in the mass production of industrial products are repetitive, physically demanding and require little thought or skill. They may also need to be carried out in environments that are hot, cold, noisy, or just generally uncomfortable. This can lead to difficulties in recruiting, and especially in retaining, suitable labour. Working conditions and the nature of the work itself can also have health and safety implications, such as the risk of repetitive strain injury, or back problems. These general considerations certainly also apply in the food industry and labour problems are a fact of life for many manufacturers. Despite the current economic crisis, the cost of labour is also rising and its availability is falling in many European countries. Automation based on the use of industrial robots can overcome many of these problems, though at a cost. But it is not just labour problems that can be tackled by automation. An automated production line can also give efficiency and quality benefits by performing tasks much more quickly and consistently than humans. Automation can reduce waste and increase output and there may also be less obvious food safety benefits, since a major source of microbial contamination, namely human operators, is largely removed from the
production process.
At first sight, the case for automation looks overwhelming — and in some sectors of manufacturing industry it is — but the food industry is different. Although some large food manufacturers have invested heavily in automation, especially in Germany and Sweden, smaller businesses continue to rely largely on manual labour, especially in countries like the UK where the industry is large but quite diverse. The obvious reason for this is the high cost, but there are other, less immediately apparent, reasons for the comparatively slow take up of automation.
For example, many food manufacturers regard flexibility as an important attribute of production. The ability to switch a line quickly and efficiently from one product to another is a useful feature when a business has a wide range of products and customers. There is often a need for short production runs followed by a rapid changeover to a different product. When the line is operated largely by manual labour such flexibility is quite feasible, but automated systems are usually designed to be fixed in location and in operation and cannot be easily changed to suit a different product or process. This is not a problem for a big operation producing a small range of products in large volumes, but for smaller businesses it is a major drawback.
An often overlooked difficulty to developing automation for use in the food industry is the fact that most manufactuting robots have been developed for the production of routine, standard products, whereas the food industry frequently involves many products that are irregular in shape and consistency.
Most robot installations are carried out by specialist systems integrators, who source off-the-shelf components from several manufacturers and then adapt them to the application in a customised solution. While this approach works well for much of manufacturing industry, the demands of food production are often rather different. End of line packaging and palletising operations can be automated quite easily using standard equipment, but the problems start when automation tries to move upstream in the process. The inherent irregularity in size and shape of food materials, plus the need to take into account food safety and hygiene, can cause serious difficulties in integrating equipment not specifically designed for the purpose. These problems can take a lot of time and money to overcome. For example, a UK-based bakery products manufacturer is reported to have spent a full year ironing out the bugs in a new automation project. The only solution to problems caused by variation in product shape was to change the product itself to make it more consistent.
Fortunately, robots and other automation equipment designed specifically for the food industry are now available and some systems integrators have alreadygained a lot of specialised food industry experience. This means that automation is now becoming a much more practical and attractive alternative for food manufacturers.
Food-friendly robots
One important area of the food industry where automation has already made a big impact is the meat sector. Large scale slaughtering and processing operations have been quick to see the benefits of automation in a sector with more than its fair share of unpleasant and strenuous tasks. Pork producers in particular have adopted automation, especially in countries with a large pig-rearing industry to support investment and research, such as Denmark and the Netherlands. In fact, the market is large enough to allow the development of purpose-built robots to perform many of the tasks previously undertaken by skilled workers. For example, market-leading Dutch company MPS meat processing systems has developed its F-line automated evisceration system of modular robots for pig processors. Each module can be fitted with a different tool to carry out a specific task, such as belly opening and neck cutting. Not only does the system eliminate a good deal of expensive manual labour, but MPS also claims that yields are increased by more consistent operation and that microbial contamination is reduced by up to 75%. This is partly because the process removes the pig’s organs in one piece, keeping the digestive tract intact, but also because the tools fitted to each robot are rapidly cleaned and sanitised between each carcass, reducing cross contamination. The system is designed to process 200 - 1,300 pigs every hour and MPS says that the payback period on the initial investment could be less than two years. Nevertheless, that initial investment is large and can be difficult to justify for smaller processors.
Unfortunately other sectors of the food industry tend to have a much more varied set of products and need a wider range of tasks to be performed. While off-the-shelf automated packaging and palletising machinery can be employed as easily in the food industry as in any other manufacturing sector, automating more sophisticated operations is less straightforward. The answer may lie in the development of robots specifically designed to suit food production.
There are a number of different types of industrial robot available, but three in particular have been developed for the food industry. The SCARA (Selective Compliant Assembly (or Articulated) Robot Arm) was first developed in the early 1980s. The SCARA design mimics the human arm in that it has a jointed two-link layout, with a rotating ‘wrist’ that enables movement in four axes. It is highly versatile and can be fitted with sophisticated vision systems, control software and a huge variety of grippers and tools to tackle a wide range of tasks. SCARAs can handle heavy objects and also have a small footprint taking up little space when retracted. Models suitable for use in food production are available from several manufacturers, such as US-based Adept Technology and Toshiba Machine from Japan. They are used mainly in “pick and place” operations.
A further development of the SCARA concept, namely adding additional rotation at the joints has produced an articulated arm with six axes of movement, which can tackle more demanding tasks. The first six-axis arm was launched in 1983 and this type is now the basis of many automated assembly and handling operations across a range of industries. There are a number of manufacturers of six-axis robot arms worldwide, but few produce a model suitable for use in food production without modification. Examples of manufacturers with food-compatible models include Swiss-based Stäubli, which has a range of robots designed for use in clean rooms. These are built with enclosed connections and are fully sealed so that they can be washed down and sanitised without damage —there are no inaccessible contamination traps. They are already widely used for a variety of tasks in the cheese and cooked meat sectors, mainly picking and packing, but also for operations like curd cutting and cheese slicing. The manufacturer Fanuc has also developed a six-axis robot for the food industry in the form of its M-430ia model. This can also be fully cleaned and sanitised and is designed mainly for picking operations.
Another robot design with food industry applications is the Delta, or parallel arm robot. This looks very different from the SCARA and six-axis robots and doesn’t at all resemble the human arm. It consists of three lightweight parallelogram arms linked to an overhead support housing the motors and actuators. The arms are connected via universal joints to a small triangular mobile platform. The platform has three axes of movement, but a fourth can be added using another arm to give rotational movement. Fitting all the heavy motors into the overhead unit means that the mobile parts of the robot are very light. This enables more rapid and delicate movements than conventional robots can manage and makes the Delta type ideal for picking and placing small, light items. Delta robots are usually vision guided, and in combination with the advanced cameras now available and a variety of grippers and tools fitted to the mobile platform, they are capable of performing intricate tasks beyond the capabilities of other types. Delta robots designed for food industry use are available and they are being increasingly used, especially for pick and place operations. Swiss-based ABB is one of the leading manufacturers of Delta robots and its FlexPicker series of Delta arms are designed to be routinely washed down and cleaned. They are now widely used for picking a variety of products from cooked meats to biscuits and can operate at speeds of 120 picks per minute or more. US manufacturer Adept Technology Inc. also has a food compatible parallel arm robot arm – fitted with four rather than the three arms of the conventional Delta type – in the shape of the Quattro robot. This too can be cleaned using normal food industry methods and has been designed with hygiene in mind. The Quattro robot is capable of very precise and rapid movement and has already found applications in the confectionery sector.
Integration makes the difference
The variety of off-the-shelf robots now available is growing fast, but they are of limited value as standalone units. Specialist integrators such as RTS Flexible Systems in the UK and Dutch company Abar Automation provide the vital link between equipment manufacturers and the end user. Systems integrators can fit robots with suitable vision and control systems, grippers and tools. Most robots come with the necessary software to program their operation, but the expertise of the integrator is still needed to make the system work effectively and efficiently. Robots can operate independently or as slave units in a network run by a central control system.
Systems integrators are also instrumental in the development of better control systems for robots. They perform an important liaison function that is helping to drive the development of ever more efficient and flexible automation systems. For example, RTS has developed its own 3-D vision system for “pick and place” robots allowing faster and more accurate operation. The design of improved grippers is another key activity. The integrators are well placed to see the limitations of existing off-the-shelf equipment and are able to modify grippers and other tools, or help manufacturers design suitable tools for new applications. A good example of this is the introduction of force/torque sensors, which can provide robot grippers with something approaching a sense of touch. This allows handling of delicate products with reduced damage and wastage.
New types of grippers and tools are constantly being developed. For example, a recent project at Bristol University in the UK looked at airflow (Bernoulli) grippers. This gripper type works by passing a high velocity airstream over the surface of the object to be picked, creating a low pressure area and a lifting force. Bernoulli grippers are usually used to lift flat rigid objects such as circuit boards, but the Bristol researchers modified the basic gripper to lift more flexible sheet foods like sliced meats, cheese and lasagne pasta. They found that the modified grippers worked well for a range of foods and were much less prone to blockage than the suction cups that are often used to lift sliced products. Ongoing research into artificial intelligence is also likely to find a number of applications in controlling robots as they are asked to perform ever more complex operations.
Of course there are still some things that robots cannot do. Even the most sophisticated robot arm cannot assemble complex multi-component foods, such as sandwiches and pizzas, anywhere near as well as a human being. But the pace of development is such that it is only a matter of time before such operations become possible. Robots also tend to react badly to extreme cold and can function poorly if required to operate in a freezer for any length of time. Since human beings can only work at such temperatures for even shorter periods, the use of robots in cold stores and in the production of foods like ice cream would be an obvious application. The problems can be solved by careful choice of lubricants and modifying existing robots with insulated components, so there is a potential market for robots specifically designed to work in cold environments.
Paradoxically, the current recession may actually boost the adoption of automation, at least by bigger businesses, as they seek to cut costs and improve efficiency through investment in technology. The cost of robots and other automation equipment is falling and the range of applications is growing constantly. This trend is likely to continue and it may be that a new generation of smaller, cheaper and more adaptable intelligent robots will eventually make the technology accessible even to smaller businesses. Some commentators believe that investment in automation may be the only way that some manufacturers will be able to survive and to still compete when the upturn arrives.
