Climatic stability guarantees consistently high precision

In 2015, Festo AG & Co. KG opened the Scharnhausen Technology Plant: the latest technology is developed using state-of-the-art equipment at what the company calls "the driving force behind the automation of the future". The focus of the plant is on the production of valves and valve terminals. In order to ensure the quality of the products, they are subjected to comprehensive function and service life tests while still on site, which are carried out in specially designed measuring rooms. "In the past, we used partially air-conditioned rooms for this purpose. However, the draughts caused by the air conditioning systems affected the measurement results," explains Rainer Hermann, Head of Measuring and Testing Technology Scharnhausen at Festo. "That's why we decided in 2014 to commission a measuring room from Nerling Systemräume GmbH."

Planning with consideration of individual requirements
Nerling even received the first enquiries back in 2013: "Festo involved us in the planning at an early stage, as the measuring room was part of the new plant concept," recalls Olaf Nerling, Managing Director of Nerling Systemräume GmbH. Specific requirements were placed on the room, which is used for series production support for machining and assembly: The grade 3 measuring room was to be located in the new building complex in Scharnhausen. The order also included a measuring equipment room in which fine probe balls (smallest diameter 0.25 mm) or probe elements are stored, which are used, for example, for measurements in bores as well as on surfaces and, in some cases, also free-form surfaces in the scanning process.

"The system was to be installed under a visitor platform and the overhang was to have a roof slope for visual reasons. This required precise media planning in order to accommodate all components and supply lines in the false ceiling," notes Nerling. In addition, a large viewing area was planned so that interested parties could get an overview of the facility. For a greater external impact, Festo also wanted the rooms to be finished in the colours of their corporate identity.

Sensitive measuring instruments require climate-stable measuring rooms
"Our measuring devices place high demands on their environment: they require a reference temperature of 19-21 °C and a relative humidity of 40-60 %," Hermann explains. These requirements correspond to quality class 3 of VDI/VDE 2627. Thus, the following temperature gradients were uniformly applied for the measuring room: 1 K/h, 2 K/d and 0.5 K/m. For cooling the measuring room, Nerling initially planned to use a cold water network that was installed on site in the new hall construction. However, when delivery and installation then took place on schedule in spring 2015, it turned out that the promised properties could not be realised at the transfer point, which led to temperature problems inside the measuring room. "However, solutions were developed together with all parties involved, which today ensure stable temperature behaviour," explains Nerling. In order to ensure consistent climate stability, additional walk-in airlocks were integrated. Thus, a measurement accuracy of 5-7 μm can be achieved at the present time.

All in all, proven Nerling systems and components were used without exception, although some of them had to be adapted to the local conditions. "Our strength lies in comprehensively understanding customer problems, developing solutions together with the customer and implementing them with our proven technology," confirms Nerling. This also includes the built-in PLC: Due to the high demands not only in terms of temperature constancy, but also in terms of humidity control, an individual control system was required.

For this reason, the system room expert opted for a freely programmable, central PLC with Nerling software. All air-conditioning components, including the supply air, can be conveniently controlled via a 15-inch touch display that is integrated into a wall of the room system and displays relevant parameters. In addition, fault messages can be output and remote maintenance can be carried out via a module. "So far, the control system has proven to be low-maintenance and reliable," says Hermann with satisfaction.

Second measuring room commissioned
Even before the first project was completed, Nerling already had an additional order to look forward to: "In the course of implementing the measuring room in Building 55 - the new building - a new requirement arose in Building 50," says Nerling, describing the situation at the time. In this case, too, we worked together to find the optimum solution and quickly found a suitable location: This was unsuitable as a production area, but could be used for the measuring room extension without any problems. Thus, an additional measuring room was created, which in this case corresponds to quality class 2. "The challenge in this case was that the entire technology had to be housed behind panels in the measuring room itself," he continues. In the end, it was decided to position all the necessary components on a technical platform in the room.

The measuring rooms were commissioned in spring 2015 and underwent a four-week test phase, which they passed without a hitch. Festo considers the cooperation in the joint project to be pleasant: "In particular, we will remember the customer-friendly service and the prompt solutions," concludes Hermann.