ADDITIVE MANUFACTURING OF HIGH PERFORMANCE OPTICAL COMPONENTS (AM OPTICS)

Brief description

The aim of the AM OPTICS research project is to further develop a reproducible process for selective laser melting (SLM) in the manufacture of optical components, for example lightweight metallic mirrors for high-precision applications. A closed technology chain using short-pulse lasers will be assembled and tested for this purpose. This research will make it possible, for the first time ever, to adapt the highly promising SLM manufacturing process to the specific task of producing components, for example metallic minors for highperformance optics applications. The required wall thicknesses and the necessary surface roughness properties of the parts can be significantly improved in this manner.

Objective

Custom-made metallic mirrors with exceptional properties are employed in spectrometers, scanners and telescopes. These metallic mirrors are optimized in regard to their optical, mechanical and thermal properties, for example laser power transmittance, dimensional accuracy, stiffness, weight or temperature stability. Selective laser melting (SLM) based additive manufacturing enables optical components, such as mirrors and their mechanical supports, to be equipped with additional functionality. lt also allows the creation of new geometries that could not be produced using the previously available manufacturing methods. Savings in materials, and therefore weight, can also be achieved. The metallic mirrors need to meet the industrial requirements for highperformance optics, for example strength, surface quality or heat dissipation.

RESEARCH AREAS

  • New design solutions of extremely light construction
  • Process and technology development for the additive manufacturing process
  • Evaluation of new material alloys containing aluminum-silicon compounds 
  • Basic research on the application of ultra-shortlaser pulses
  • Analysis of material properties (residual stresses, localized defects, microstructures, anisotropy etc.)
  • Use in combination with galvanic applications
  • Ultra-precision diamond machining and surface correction using MRF technology (Magnetorheological Finishing)
  • Evaluation of existing coating systems
  • Analysis and confirmation of stability
  • Demonstrators and verification

Method

All relevant steps from part design and material formulation, plant and process technology, right through to postprocessing by coating or ultra-precision turning using diamond tools will be analyzed and suitably further developed. An experimental SLM machine will be constructed for this purpose to enable all the necessary process steps to be optimally tailored to one another. Three example metallic mirrors will be investigated:  A highly dynamic scanning mirror that needs to be laser stable and weight optimized. An ultralight spaceflight mirror that needs to fulfill stringent requirements in regards to strength for the rocket launch and dimensional stability. A cooled laser mirror that needs to be able to efficiently dissipate the applied radiant heat by means of integrated cooling channels.

Results and potential applications

This research will make it possible, for the first time ever, to adapt the highly promising SLM manufacturing process to the specific task of producing components, for example metallic mirrors for high-performance optics applications. The required wall thicknesses and the necessary surface roughness properties of the parts can be significantly improved in this manner. The project results will secure the competitive advantage of German high-tech companies, enable the development of innovative products, and help open up new growth markets in manufacturing, laser material processing, and aerosDace.

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Federal Ministry of Education and Research

This research and development project is funded by the German Federal Ministry of Education and Research (BMBF) within the “Innovations for Tomorrow’s Production, Services, and Work” Program and implemented by the Project Management Agency Karlsruhe (PTKA). The author is responsible for the content of this publication.