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The falling price of technology, improved performance and rising labour costs are behind a massive increase in the take-up of industrial robots. And, as ANNA KOCHAN reports, the automotive sector is driving forward the search for new applications

The plummeting prices of robots and rising cost of labour are boosting robot sales across the world. Never before have so many orders for industrial robots been placed by industry, according to Jan Karlsson of the United Nations Economic Commission for Europe.

His comments follow the publication of a worldwide survey by the UNECE (in cooperation with the International Federation of Robotics) of industrial robot orders, which showed a 20% increase in 1999 compared with 1998.

North America produced the most dramatic results, with a massive increase of 60%. Europe’s orders rose by a more modest 12%, but this is not unimpressive since the previous year’s figure was already up by 31%.

The severe shortage of labour that was largely responsible for sparking off a drive towards automation in Japan in the 1980s is now happening in North America and many European countries, researchers say.

But the falling price of robots and rising labour costs have also played a part. Robots being sold in 1999 were priced 40% lower on average than those sold in 1990, and offered much higher performance. The same period saw labour costs in the US, for example, rise by more than 30%. Another factor cited is the 35-hour working week that has already been introduced in some Continental European countries.

The automotive industry is the fastest growing sector for robot applications. The survey reported a 24% increase in orders from the automotive sector in 1999, compared with a 14% rise for all other manufacturing sectors combined. And as new automotive applications for robots are continuing to be developed, the growth is expected to continue.

While vehicle manufacturers will continue to practise mass production methods in the future, it will be mass production with a difference, because of the trend towards greater numbers of models but smaller volumes of each. In this environment, the role of the robot is becoming increasingly important, particularly in applications that can lead to fewer hard-tooled processes.

Cutting out press tools

One example is robotic plasma cutting, which eliminates the need for clip and pierce tools. These are the press tools that trim a pressed panel, finishing the edges and piercing holes in it. `They cost up to £500,000, depending on the complexity of the panel,’ says Clive Montague-Brown, recently retired managing director of Contour Cutting Technologies in Andover, the company which developed the new application.

He claims that CCT’s robotic plasma cutters are economic for production volumes of 5,000-10,000 vehicles a year. It is based on the French-built Staubli robot, equipped with a plasma torch that CCT developed specifically for the application.

CCT robotic plasma cutting systems are used at the firm’s own plant in Andover and at Panel Technology, the Hinckley-based subsidiary of Sertec Group Holdings. Both are employed for subcontract work. Sertec obviously believes the robotic plasma cutting technology has a rosy future, as it bought a controlling interest in CCT in May. `Every press shop worth its salt should have a CCT plasma cutting system because of the flexibility it can provide,’ says Graham Mosedale, group managing director at Sertec.

In a totally different application, robots are again taking on a task that eliminates hard tooling, although this is not the main advantage. The damper pads put in the floorpans of vehicles to absorb noise and vibration are now being applied by a robotic spraying process rather than by operators fitting pre-formed die-cut pads into place.

The method was developed by Fanuc Robotics North America and has been operating for almost a year in a vehicle assembly plant. The advantages are numerous, Fanuc claims.

`The sprayable damper technology can reduce the weight of the vehicle by three to five pounds, give material savings of $5-$10 per vehicle and reduce manpower,’ Ray Guzowski, senior staff engineer at Fanuc says.

In the first industrial application, four robots have been installed, two either side of the production line. The Fanuc S-500 robots are fitted with pumping and spraying equipment for moving the damper material from a 300-gallon drum to the applicator tool on the end of the robot arms. They have taken over the work of more than two operators, and possibly as many as four, says Martin Rola, manager of paint product application at Fanuc.

In the future, as more pumpable, sprayable materials are developed, a single robot system could be used for multiple applications, including foam cavity fill, seam sealing, as well as laying sprayable damper. `It helps to improve the business case for sealing automation,’ Ray Guzowski comments.

Another process that car companies could start to adopt more widely as a result of developments in robotic systems is clinching. This is a little-used technology today. Where large workpieces such as the floorpan of a car are involved, hard automation was the only solution available in the past because of the heavy tooling needed to apply the high forces required. A France-based consortium including Fanuc, robot gripper specialist CCMOP and a French inventor, Michel Darmon, has now come up with a robotic solution.

Systems have already been delivered to Peugeot in France and DaimlerChrysler in Germany. Michel Darmon expects to see further applications because of the numerous advantages of clinching. For example it is a cold process involving no deformation of the material, and it can be used for joining dissimilar sheet materials, including pre-painted panels. The same end-effector, he says, can be used for robotic riveting as well.

Looking to the future, two new welding processes have been developed that could provide work for robots in years to come. One is a plasma spot welding process from Arc Kinetics in Coventry, whose potential will be realised once aluminium cars become more widespread.

Potential benefits

Russ Hughes, technical director at Arc Kinetics claims it will enable robots to spot weld aluminium cars in much the same way as resistance spot welding is now done on steel cars, with the added benefit that plasma welding only requires access to the parts from one side. The first application of the technology is in the production of air conditioning vents.

The second new welding process is a development from Israeli company Pulsar. Known as magnetic pulse welding, it uses very high electric current for a minuscule period of time to set up strong opposing magnetic fields around the two parts to be joined. The parts are driven into one another with such force that they are welded together. This method is particularly suitable for welding dissimilar metals.

The latest version of the technology, involving a split coil system, would use a robot to open and close the coil around the parts to be welded. According to Ben Spitz, Pulsar marketing director, strong interest is being generated among vehicle manufacturers who are looking at space frame vehicle production.

At some time in the future, Spitz believes, vehicle makers could use split coil magnetic pulse welding for joining the aluminium struts of space frames to the steel hubs. However, this is a long way in the future, as the technology is still at prototype stage.