In all branches of industry demands on quality are increasing and the automotive industry is no exception. Not only is technical performance an issue, but also visual aspects, which becomes evident especially during dimensional inspection of the body parts.

An example of a successful quality process, which provides economic benefits, is the cooperation between Horst Witte Geraetebau and Adam Opel AG in Ruesselsheim, Germany. (The Adam Opel AG is General Motors Europe.)

Witte, from Bleckede near Lueneburg, has developed a fixture that allows the user to mount each individual component and finally, the body accurately as a whole. This is necessary to check the fit of actual parts that have previously been designed on a CAD screen. Measuring takes place with laser trackers and the low error tolerance in the range of 1/10 mm is convincingly low.

Until recently Opel built individual, elaborately machined clamping fixtures for each new car, which were later scrapped as soon as that vehicle was no longer in series production. The procedure had to be improved.

A decision was made in favor of the modular fixturing system Alufix from Witte. This modular system, conceived as a range of standard components, is absolutely variable and flexible. The fixture itself is reusable and adaptable.

This concept allows mounting of the whole vehicle range, from the largest to the smallest car model, variable in height and width.

The configuration in the analysis center at Rüsselsheim, Germany, consists of a base plate on which the Witte meisterbock is mounted. This consists of three cubes (Witte FixBase), which can be positioned differently according to the Opel model. Adapters from the Alufix Classic range hold clamps and pins, which ensure that each body part can be placed nominally in x, y and z in the coordinate system.

“Using this modular and accurately repeatable fixturing system from Witte has meant a quantum leap in our checking technology,” says Matthias Becker, manager in the Opel quality assurance center. “We examine more selectively, in shorter time and with higher quality intensity.”

Because the decision for Witte technology significantly increased benefits, and, due to the reusability of the system, lowered costs, the project has meanwhile been nominated for the internal GM Award.

The Witte company from Bleckede has become a system partner for Adam Opel AG, with whom cooperation takes place easily and improvements are implemented quickly.

“Experience gathered during practical applications is integrated into product development at Witte,” says Dirk Kissinger, project manager, body measuring technology, “even if it concerns details like the accessibility of clamps.”

 This kind of product development in line with standard usage in an automatic control loop is never ending, because the bar for quality requirements at Adam Opel AG is constantly being set higher. “We owe this to our demanding international buying public,” says Matthias Becker. His contact person at Witte, area sales manager Stephan Sauthoff, adds, “Being satisfied with what has already been achieved means you fall behind.”