All ABB assembly and welding robots, used in the car-body production of the Volvo C70 convertible in the Pininfarina Sverige factory in Uddevalla, are equipped with tool systems and swivel tool changers from Robot System Products AB. After assembling the front, the middle and the rear parts in distinct robot cells, these 3 parts are assembled in the floor assembly, thus forming the floor of the car body. During these assembly processes, the robot accessories from RSP play an important role and have proved their high reliability and efficiency over many years.
The first RSP tool systems with a transformer gun for media transfer and tool changing were already introduced in 1986, long before the factory became Autonova (1994), Volvo (2000) and Pininfarina (2005). The installation of the swivel tool changers for spot welding in 2006 enabled Pininfarina to become the first car manufacturer worldwide to build 3-part hardtop roofs.
Assembly in the floor lines
A front, middle, and rear floor are the three main parts of the floor of the Volvo convertible C70. "We receive these elements finished moulded from an outside supplier, and they are welded together in our first line. This is the body's base plate", the Volvo maintenance technicians Håkan Olsson and Maths Karlsson explain. Then the car floor is conveyed to the next line, where additional floor parts are welded solidly, such as the rear wheel and seat backs. As soon as the indexing bolts of the floor groups lock into place, the floor is finished welding both manually and by robot.
Assembly of the sides, hood, trunk and doors
The body's sides are built in two separate lines and transported via a pallet system to the main line where they are welded to the body by the robot. The welding methods used are resistance welding, soldering, laser and MIG welding. In the end line, the doors, roof, fenders, hood, and trunk are installed and manually welded. There are several reasons to perform quality control on the finished body, before it is sent to dipping and painting.
Corrosive protection and paint shop
The bodies are loaded on trucks for transport to the Volvo factory in Gothenburg. There they are cleaned and rust protected. Then, the bodies are ready for painting and assembly at Pininfarina AB in Uddevalla.
Swivel tool changers
The tool changer STC350SWP has been developed by Robot System Products for spot welding applications with robots. It is available as a swivel, or as a swivel with tool changer. All the cables and hoses have been specially adapted to the structure and movement pattern of an ABB robot, which enables the speed, acceleration and reach of the robot to remain the same as it would be for an "empty" robot. All RSP products are available as 3D models and therefore they support the off-line programming of the robot. The system is supplied with all the necessary parts to ensure fast and simple installation from the robot's connection point. All media such as compressed air, cooling water, welding current, and electrical signals are supplied. Because of the latch-free "True ConnectTM" system, the robot can carry this large and heavy welding gun with a built-in transformer to the same position with highest accuracy throughout its whole life cycle. The latch-free locking allows high performance to the robots as well as short cycle times.
The maintenance technicians Maths Karlsson (38) and Håkan Olsson (41) appreciate the extremely high reliability and long life of the tool systems and swivel tool changers from RSP. Some RSP robot accessories are still in operation since the very beginning. However, the swivel needs maintenance about every 2 years, but it saves the dress pack harness for over 5 years. The positioning accuracy and the precisely controlled welding current greatly influence the quality of the car-body floors. This is very important, especially with regard to cars without a roof.
Both technicians are very satisfied with the service, maintenance trainings and the technical documentation from Robot System Products. They also praise the high technological standard, the easy mounting, the simple use and the high protection class IP67 of the STC350SWP swivel tool changers.