BAK Boysen Abgaskomponenten GmbH mainly manufactures exhaust systems including top-range engines for the BMW 7 series, Audi A8 and VW Phaeton. Production consists of many variants and small batch sizes. As a system partner to the BMW group, Boysen has jointly developed the exhaust manifold catalytic converter module for the BMW six cylinder NG-R6 engine. Unlike the other production areas at BAK, the new assembly line had to be designed for large series production.


The three main assemblies, exhaust manifolds, catalytic converters and exhaust pipes, are manufactured independently of each other in different areas within the assembly line. The sheet metal exhaust manifolds are manufactured in six sequential steps. In order to optimise the welding quality each MOTOMAN robot only welds one circumferential seam. Robot 1 welds the middle inlet pipe of the manifold to the collector. Robot 2 welds the right and robot 3 the left inlet pipe. The robots 4 to 6 finally weld, one after another, the sheet metal flange fillet with the middle, the right and finally the left inlet pipe of the exhaust manifold. The production of the catalytic converter also requires high precision, which is one reason why Boysen has completely automated the so called canning process. Finally, the exhaust pipes are produced in two sequential steps – first a threaded socket and then an outlet flange are welded onto the prefabricated pipes. In the final assembly a robot welds a manifold, a catalytic converter and an exhaust pipe together in two work operations.


The modules undergo a 100 percent final inspection before delivery, where every assembly is automatically checked for evenness, geometry and leak tightness in a 3D robot measuring cell. This is usually a challenging process for quality assurance, but the combination of measurement technology and MOTOMAN robots made the design of a very flexible measuring cell possible. With the many possibilities for visualisation and documentation provided by the measurement results, production is now 100% traceable. Therefore the Quality Assurance Department now has a tool with which it can prove at any given time that parts meet the requirements of the technical specifications. Daily production capacity over a two shift operation of the new production line is producing 2,400 exhaust manifold catalytic converter modules.

Motoman welding robots at BAK Boysen


BAK Boysen Abgascomponenten GmbH


Exhaust manifold catalytic converter







System Components

MOTOMAN HP6 welding robots
MOTOMAN UP50 robot




Robots realise cost effective production of exhaust system parts