"The demands on measuring technology have increased significantly in recent years," explains Ulla Böhringer, Managing Partner at Philipp Hafner. "In the automotive industry in particular, component tolerances are becoming ever tighter, while at the same time the variety of workpieces is increasing." The company is one of the leading specialists for sophisticated, customer-specific production measurement technology. The core competence of the Swabians lies in the tactile measurement of workpieces with tight tolerances: The machines precisely measure the geometry of three-dimensional parts. The special feature is that these systems are not located in air-conditioned measuring rooms at the customer's premises, but are integrated directly into production lines. This means that they have to perform reliably even in the event of temperature fluctuations or dirty surfaces, as even the smallest deviations from the permissible values can significantly disrupt processes or cause damage. The majority of users come from the automotive industry. The components to be measured can be found in critical areas such as the steering, axles, engine, the entire drivetrain and even the rims in the wheels.

"What sets us apart?" Ulla Böhringer doesn't have to think for long. "We have a high level of consulting expertise and can develop systems that precisely meet the wishes and requirements of our customers." This also includes a new concept for a fully automatic system - especially for pistons in combustion engines. It can not only measure these, but also assemble piston rings, piston pins and circlips as well as weigh the pistons, mark them with ink or laser and finally inspect them using camera technology.

"Because this is not a classic special machine for production metrology, we are achieving an important new development with this system," explains Tim Eißele, Project Manager Design at Philipp Hafner. The development consists of a transport system up to 100 meters long with workpiece carriers. This connects individual stations, which the user can adapt to his requirements and expand at any time if necessary. The project manager takes a workpiece carrier, places it on the conveyor belt and places the component on it - a piston for a car manufacturer. "The customer expects high processing quality in an extremely short time," he says and starts one of the stations.

The workpiece carrier is pulled into the station by the transport system via a feed unit and docks there. A holder moves through it from below through a hole and lifts the piston until it reaches the assembly position for the respective piston ring. "The system not only lifts the workpiece to the appropriate height," explains Eißele, "depending on the station, it also has to be positioned at a certain angle or rotated 360 degrees."

The keyword is downsizing

"Whether the respective station is assembling, measuring or carrying out other steps, the movements must be fast and dynamic in order to meet the required cycle rates," explains Eißele. While searching for suitable components that could perform these movements, the design team came across the new linear rotary modules from its supplier partner Dr. Tretter from Rechberghausen, just under 40 kilometers away. Together with the torque shaft, the spindle forms a single unit. This allows them to implement both separate and combined motion sequences such as positioning, linear and rotary movements. "Conventional solutions usually require at least two elements for translation and rotation," says Holger Schmidt, Technical Sales at Dr. Tretter, who is supporting Philipp Hafner with this project. A linear guide, for example, implements the vertical movement, a spindle axis the horizontal movement and a pivot bearing takes care of the rotation. "In addition, the number of components would take up much more installation space with a conventional system and the drives would have to be designed accordingly in order to be able to move the mass quickly," says Eißele.

This is not the case with the linear rotary modules. They require little space and the drives can be significantly smaller due to their lower weight. Designers use them to implement dynamic applications, particularly in automation technology, and at the same time achieve positionally accurate motion sequences. ee