Efficient production of functional samples

im Bereich der Ultrapräzisionszerspanung

In the development of assemblies or systems containing high- and ultra-precision components, the production of prototypes for functional sampling is still of central importance. This is especially true for optical systems.

With the desire to support the prototype phase of a development project with the production of parabolic mirrors, the Leica Geosystems AG aus Heerbrugg therefore recently approached RhySearch.

 

Challenges

Parabolic mirrors are typically used for focusing collimated light. Three aspects are of central importance in manufacturing: the shape accuracy of the mirror surface, a sufficiently small roughness to avoid diffuse reflection, and the positional deviations with respect to defined features on the component, with the help of which the positionally accurate assembly of the mirror component in the overall optical system is ensured. The latter in particular requires a well thought-out process design that minimizes sources of error. The core of Leica Geosystems' task, however, was an additional microstructure that had to be embedded in the parabolic surface and also fulfill the three aspects mentioned above. Ultra-precision turning, also known as diamond turning, is a widely used technology for the production of metal mirrors and offers the prerequisites to overcome the challenges mentioned. RhySearch is the only research institute in Switzerland that has the corresponding machine infrastructure and offers related services.

Process design and implementation

The microstructure required a departure from the classic configuration for turning parabolic mirrors, in which the parabolic axis coincides with the spindle axis of the lathe. The workpiece is mounted outside the spindle axis ("off-axis") if necessary. Any other positioning on the spindle entails the need for three simultaneously used NC axes, and therefore more demanding machine programming as well as a production speed limited by the machine dynamics. In close exchange between Leica Geosystems and RhySearch, the decision was made to use on-axis complete machining of the mirror surface, including the microstructure, in combination with a sophisticated fixture design.

At its Buchs site, RhySearch has an air-conditioned manufacturing laboratory with machine infrastructure for diamond turning and 5-axis simultaneous milling according to the latest state of the art in terms of achievable accuracies. The entire process chain consisting of process design, fixture design and manufacturing, and ultra-precision machining is thus available in-house to efficiently implement prototype and functional sample production.

In the case of the Leica Geosystems order, this is exactly what happened: Figure 1a shows fixture production on the 5-axis milling machine type Kern Micro HD and Figure 1b the fixture including workpiece made of aluminum mounted on the diamond lathe type LT‑Ultra MTC 650 UP. Both machines are located only a few meters apart and use a zero point clamping system of the same type.

Summary

The physical proximity of the two institutions involved in the St. Gallen Rhine Valley enabled the efficient and rapid exchange of components, so that functional tests at Leica Geosystems could be carried out quickly and results could flow back into further process optimization at RhySearch. Finally, it was possible to successfully verify the desired parabolic geometry with microstructure in a short time, so that risks could be minimized and the product launch of the entire system could be transferred to the next phase. Pascal Hutter, the engineer in charge at Leica Geosystems, particularly appreciates having a partner in the immediate vicinity with infrastructure and know-how in the technological niche of diamond machining. The industry clearly benefits from this, Hutter continues. Marco Buhmann, research associate at RhySearch, is also satisfied and thanks Leica Geosystems for the trust placed in him. This made it possible to openly discuss the advantages and disadvantages of various process designs and ultimately decide together on the optimal solution.

from Marco Buhmann

Leica Geosystems part of Hexagon

Leica Geosystems, a Hexagon company, has been revolutionizing the world of surveying for over 200 years, providing complete solutions for professionals worldwide. The company is known for its premium products and the development of innovative solutions for the capture, analysis and presentation of spatial information. That's why professionals in many industries, including surveying and GIS, construction and machine control, manufacturing, aerospace, and public safety, trust Leica Geosystems. Precise instruments, advanced software, world-class service and support, and comprehensive services create value for Leica Geosystems customers every day as they shape the future of our world.

Hexagon

Hexagon is a global leader in digital reality solutions that combine sensors, software and autonomous technologies. We use data to increase efficiency, productivity, quality and safety in industrial, manufacturing, infrastructure, public sector and mobility applications.

Our technologies help shape manufacturing and people ecosystems so that they function in an increasingly connected and autonomous way - ensuring a scalable, sustainable future.

Hexagon's Geosystems business offers a comprehensive portfolio of digital solutions that capture, measure and visualize the physical world. They enable data-based transformation within industrial ecosystems.

Are you also facing a challenging problem in the field of (ultra) precision manufacturing? Contact us, we will be happy to advise you!

 

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