The project “Forward-looking methods and processes for precision assembly and process monitoring for novel combustion engines’ has the objective of continuously optimizing the quality of the engine assembly. The use of advanced technologies in the areas of robotics and sensor technology is intended to help eliminate uncertainties during engine assembly.

The project is the work of the group “Resource-efficient mechatronic processing machines” of the Fraunhofer Institute for Machine Tools and Forming Technology IWU under the management of Prof. Dr.-Ing. Gunther Reinhart.

The automated assembly technology of the IWU scientists would identify the defect early, during engine assembly, and forward the corresponding information or, for certain assembly processes, would not permit the defect to occur in the first place.

Monitoring the process throughout is not possible, since the engine continues to be assembled mostly manually. And engines are becoming more complex all the time. This can cause increased levels of rework.

—Christoph Sieben, IWU

The researchers first catalogued the status quo, evaluating current data on documented, assembly-related engine problems for in-line and V-type engines over the past five years. The focus of the analysis was on the parts used and on the processes involved.

The Fraunhofer team generalized the engine assembly sequence and broke it down into eight blocks. The individual assembly functions are also recorded in a standardized way. This makes it possible to assign errors during assembly to uniformly defined assembly sequences and assembly functions. As a result of this generalization of engine assembly, the analysis can be utilized for all kinds of engines. “We now know which assembly sequences require action,” says Christoph Sieben.

The project group wants to develop new automation solutions next. The core piece of the test facility is a new type of lightweight robot: it weighs only 16 kilograms but can lift up to 7 kg. The KUKA robot is very sensitive and flexible, unlike other traditional robots that can perform tasks only within certain parameters. The researchers are now looking for new ways to combine innovative sensor technology and robots.

For example, we are pondering how a transfer from medical sensor technology to industrial processing could be effected.

—Christoph Sieben

A high-performance control technology can be developed by integrating sensor systems of many variations: ideally, the robot will not only detect the problem, it will also solve it. Camera systems that record the directional orientation of a part are a current example. If it does not correspond to the standard, the robot can decide whether the part will be used or if it has to be replaced.

The process monitoring system that is to be developed further on this basis has the ability to automatically deduce the inspection criteria and the required tolerances during the entire assembly process and then to react, said Sieben. The project will end in 2014. The plan is that the prototype will then be ready for series production.