At 120 revolutions per minute, an imbalance would have devastating effects. Efficiency is also highly dependent on the blade’s precision and positioning. Such turbines are manufactured at Andritz Hydro GmbH in Ravensburg, Germany, a division of the Andritz Group.
In order to optimise the production and alignment of these complex components, Andritz Hydro GmbH sought a solution to carry out measurements with narrower tolerances and at higher speeds. After researching thoroughly and testing multiple products, Andritz Hydro GmbH purchased several portable coordinate measuring machines from FARO, which were customized for their measurement needs: several FaroArms and a FARO Laser Tracker for dimension monitoring, CAD comparisons and iterative alignment procedures.
Measuring a turbine wheel is complex and challenging because of the dimensions of the,components being measured. In addition to that, the components are not freely accessible from all sides, i.e., mounted on a measurement bench. Andritz Hydro GmbH benefits from the portability of FARO measurement solutions, which enable the company to carry out precise and reliable measurements in the production area, warehouse and even onsite.
Measurements are usually carried out at the production site amidst other components and tools, using FaroArms in different sizes and a FARO Laser Tracker. These mobile, tactile measurement instruments are ideally suitable here: while there are not many measurement points, these are often in hard to reach places or even hidden. Due to their versatility, FARO measurements solutions are not only useful for the quality assurance of blades, but also for many other tasks, such as analysis measurements, incoming goods inspections, finding cracks in raw castings, the alignment of welded components, etc.
For several years now, PolyWorks|Inspector software has been used for the organization and analysis of the measurement data. The alignment functions and the functions related to the analysis and export of data are particularly popular with customers. Christoph Müller Henker, who works in Measurement and Testing Technology at Andritz Hydro, appreciates the fact that the oftware is not limited to standard situations: “We can take a variety of paths to reach our goal using PolyWorks. We use the many export and import options and interfaces to find our own solutions.” In addition to that, each division of the turbine manufacture is a “customer” and has needs when it comes to processing data. The software has no trouble handling all of the respective formats.
While the challenges related to the size of the components are no longer an issue, there is no everyday routine. Andritz does not use mass production; each turbine is one of a kind. The measurement requirements are therefore ever-changing. “Each measurement is its own project”, explains Yener Korkmaz, Head of Measurement and Testing Technology at Andritz Hydro, who is responsible for quality assurance for incoming goods and in-house production.
Size and accessibility mean that the FaroArm and FARO Laser Tracker have to be moved around a lot. The software speeds up the implementation of the measurement instruments. It is enough to align the respective measurement instrument within the coordinate system at a new location. The organisation of the measurement data and the management of the various device positions within the coordinate system are controlled by the software. FARO Laser Trackers and FaroArms can also be combined in one measurement process, which increases both flexibility and range.
When changing locations, the FaroArm is calibrated via the tracker’s coordinate system. The software registers the measurement arm in the coordinate system of the Laser Tracker, without needing to record reference points. This combination uses the classic FARO TrackArm.
For hard to reach measurement points on the turbine wheel or shaft, the PolyWorks App|Talisman for mobile devices such as iPhone or iPad is extremely useful. Measurements can be initiated and project data accessed from a PC using remote access. The measurement technician can monitor the measurement data and correct measurement errors directly from the component. The turbine manufacturer has also found these reliable, state-of-the-art measurement systems useful for other applications. The correct positioning of the individual components can be determined prior to initiating the welded root seam. The systems are also used for balancing the welded components, with a maximum position tolerance of 0.4 mm.
Today, this takes only two hours. Using wire and solder, it previously took at least two days to bring the individual elements into position and ensure concentricity. Furthermore, because the equipment is mobile, the quality of supplied components can be tested directly at the installation site.