KUKA robots mount and weld silencers at Roth-Technik

At Roth-Technik, an extensive automation solution has doubled the production of silencers for a commercial vehicle manufacturer.

Such a complex robotic system with multiple components is exceptional for Austria: “Line 8” at Roth-Technik incorporates a total of 10 KUKA welding and handling robots linked together in one manufacturing line. Only the automotive industry has comparable solutions. Roth-Technik from the Lower Austrian town of St. Aegyd is boldly treading completely new paths in production.

Roth-Technik is an original equipment manufacturer and system partner for the European commercial vehicle industry, and has been manufacturing exhaust systems for trucks, tractors, forklifts and buses, etc. since 1983. This complex manufacturing line is used for a new generation of silencers for MAN which comply with the EURO 6 exhaust emission standard.

A KUKA robot welding silencers at Roth Technik

Innovative automation solution with KUKA robots

The automotive industry is continuously raising the quality standards demanded from component suppliers, this being one of the reasons for the innovative automation solution involving KUKA robots. In addition, the industry is expecting greater capacity for higher quantities, while furthermore new legal regulations on emissions limits in exhaust purification are imposing the need for product innovations and, with that, enormous flexibility in production.

Last but not least, the weight of the parts used in the Roth-Technik silencers, ranging from 120 up to 150 kg, is increasingly exceeding the handling ability of human workers. There was an urgent need for automation. “Line 8” is used for making multiple variants of silencers, i.e. it had to be possible to expand the manufacturing line easily, as well as to convert it for other production types. In addition, it had to be possible to increase the quantity as required. This required significantly reducing the cycle time.

At full capacity utilization, that meant doubling the produced quantity from 60 to 120 per shift. In addition, two existing machines had to be integrated into the new solution, and were regarded as fixed parameters. The automation line had to link not only handling but also arc welding tasks. Furthermore, it needed to be possible to move parts ranging from 150 kg down to delicate, small items.

Mounting and welding robots as teams

In total, the production line incorporates 20 different stations, 12 of which are straightforward welding stations. The three KR 270 R2700 ultra robots are mounted on the KUKA KL 1500 linear unit and transfer the silencers to the various workstations. In order to attach various smaller, individual parts onto the silencer, two small handling robots of the KR 5 R850 type are integrated into the welding cells.

The robots pick up individual parts from a magazine and position them exactly against the silencer in order to be tacked or welded on by the welding robot. Five KR 16 L8 arc HW welding robots complete the manufacturing line. This type of robot from KUKA is regarded as the specialist for arc welding, above all when it comes to welding relatively large components. The hollow wrist design with a 60 mm passage opening integrates the torch and fluids supply from a wide range of manufacturers, meaning that the welding packages are always protected; this also guarantees greater stiffness and lower vibrations.

Scalable payload and reach

Using the three KR 270 R2700 ultra robots brings decisive advantages. The robots can move parts within a reach of 2700 mm, with a payload of up to 270 kg. The payload and reach can be graduated with such precision as to be suitable for each application.

The KR QUANTEC series is particularly characterized by the robot design: slender, with 25% less volume than the previous KUKA series, adding up to a reduced space requirement but improved accessibility.

The stiffer mechanical system, improved path accuracy and greater modularity make this jointed-arm robot the market leader in terms of technology. In order to attach various smaller, individual parts onto the silencer, two small handling robots of the KR 5 R850 type are integrated into the welding cells.

KUKA KR QUANTEC robots transport the heavy silencers to the workstations.

Best repeatability and highest quality

Generally speaking, this type of robot is used where the greatest levels of speed and precision are required. Five KR 16 L8 arc HW welding robots complete the manufacturing line. This type of robot from KUKA is regarded as the specialist for arc welding, above all when it comes to welding relatively large components.

This new type of robot has a repeatability of ±0.04 mm, which is the best in its class, incidentally. The new solution is not only more efficient; it also reduces the workload on employees and protects the product. This means higher quality requirements can be met. Since the ever-heavier parts no longer had to be handled manually, damage can be avoided.

The KUKA welding robots KR 16 L8 arc HW have the best repeatability in their class.

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