The Laboratory for Precision Machining (LFM) is a research and development centre dedicated to the practical development of ultra-precise mechanical manufacturing processes. It offers industrial companies and research institutes solutions for the production of sophisticated optical and mechanical components, which today play a key role in numerous innovative fields from medical technology to astronomical research.
The LFM conducts research in the fields of ultra-precise mechanical manufacturing such as turning and milling with diamond tools on ultra-precision machines, precision grinding and polishing, and micro manufacturing. High-precision production measurement technology is also an integral part of these activities. The LFM works in particular on the development of process chains and material-oriented manufacturing in the field of mould making for complex optical components as well as for precision and micro components.
Since its foundation in 1992, the Laboratory for Precision Machining (LFM) has successfully dedicated itself to the practical development of ultra-precise mechanical manufacturing processes. The LFM offers industrial companies and research institutes solutions to problems for the production of sophisticated optical and mechanical components, which today play a key role in numerous innovative fields ranging from medical technology, automotive and lighting technology, optical and precision mold making, industrial metrology to astronomical research.
The research focus of the Laboratory for Precision Machining is particularly on the development of process chains and material-oriented manufacturing in the field of mould making for complex optical components as well as the manufacturing processes for precision and micro components. The focus is on ultra-precise mechanical manufacturing processes such as turning and milling with diamond tools, precision grinding and polishing as well as micro manufacturing by micro milling and micro grinding.
Diamond machining processes can be used, for example, to produce optical freeform surfaces and aspheres or microstructured optical components such as microlens arrays, Fresnel lenses or diffractive elements. Precision grinding processes and polishing technologies in turn open up the processing of further classes of materials, e.g. the manufacture of optical mould inserts or lenses made of brittle-hard materials. The development of special manufacturing processes including their periphery is in the foreground here. Micro-machining processes play a central role in the manufacture and structuring of forming tools for micro- and precision forming technology and other components subject to high tribological stress. The high-precision machining of medical technology materials, such as implant ceramics, is also opened up by the technologies of micro-machining.
For research work, the LFM has various multi-axis ultra-precision machine tools for component machining in a 300 sqm air-conditioned workshop area. High-precision production measurement technology is also an integral part of the activities. The analysis of process variables such as machining forces or structure-borne noise emission is used in combination with component characterization for process development. A wide range of high-resolution measuring instruments for form and surface evaluation and plant characterization are available for the evaluation of machined surfaces. These range from atomic force microscopy, white light interferometry and confocal microscopy to coordinate metrology, aspherical profilometry and interferometry.
The only known and effective treatment for cataracts is the surgical removal of the opacified natural lens, with refractive error correction achieved through the implantation of an intraocular lens (IOL).
This project aims to develop a process for the efficient and flexible production of freeform IOLs made from hydrophobic acrylate materials. The focus at Leibniz-IWT is to establish a novel fast-tool-servo (FTS)-supported diamond turning process, along with a corresponding clamping-cooling system, enabling the parallelized, precision production of IOLs from low glass transition temperature (Tg) polymer materials.
Cooperation: Amiplant GmbH
Funding: BMBF KMU-innovativ-Produktionsforschung
Contact:
M.Sc. Wei Wang
Tel.: +49 421 218 51162
E-Mail: wang@iwt-bremen.de
In this project, normal and shear stresses in the contact area are determined for the first time for diamond grinding wheels with grain sizes above D301 for ductile machining of brittle-hard materials.
This allows the description of the primary cutting mechanisms by means of material-physical parameters with the overall aim to create a process model. Therefore, a complete description of the grinding wheel topography is used to determine the contact surfaces with the workpiece. The measurement of process forces, in combination with the contact surfaces, enables the calculation of normal and shear stresses in the contact area.
Funding: DFG
Contact:
M.Sc. Barnabas Adam
Tel.:+49 421 218 51170
E-Mail: adam@iwt.uni-bremen.de
The project uWe is dedicated to superimpose an ultrasonic field onto the work piece during machining using an ultrasonic bath. Particular machining experiments with cutting grooves and particular surfaces with monocrystalline diamond tools are performed on steel, brass, copper and aluminium.
The process forces show a decrease of up to 50 % with the increase of the ultrasonic energy, while the surface roughness remains undisturbed by the ultrasonic energy. The results indicate that the ultrasonic induced softening has an influence on the cutting process, which could improve the machining of brittle hard materials in the future.
Funding: DFG
Contact:
Dr.-Ing. Oltmann Riemer
Tel.: +49 421 218 51121
E-Mail: riemer@iwt.uni-bremen.de
Micro-milling is essential for producing precise components in microelectronics and medical applications, valued for its flexibility and reliability.
One critical application is dry micro-drawing, which eliminates contamination risks but leads to increased friction in the tribological interface. This research aims to establish a scientific understanding of the tribological properties of micro-textured surfaces on hardened tool steels with PVD coatings. The objective is to develop design strategies for micro-textured and PVD-coated tool surfaces, ensuring effective performance in dry forming processes under specific load conditions.
Cooperation: Leibniz-IWT FT/WT
Funding: DFG
Contact:
M.Sc. Pooria Farahani
Tel.: +49 421 218 51165
E-Mail: farahani@iwt.uni-bremen.de
In the transfer-project T08 of the CRC 136, the dependence of local material loads based on the tool geometry in energy-assisted diamond machining of silicon is determined.
With the material load-oriented approach of process signatures, here applied to silicon for the first time, the influence of a targeted variation of mechanical and thermo-mechanical material loads on geometrically determined machining is examined.
Cooperation: Gruppe Matzdorf GmbH
Funding: DFG (SFB/TRR 136)
Kontakt:
Dr.-Ing. Oltmann Riemer
Tel.: +49 421 218 51121
E-Mail: riemer@iwt.uni-bremen.de
The aim of this industrial project is the further development of the ultraprecision turning technology for the manufacturing of multi lens mounts for the METIS (“Mid-infrared ELT Imager and Spectrograph”) sub-instrument SCAO (“Single Conjugated Adaptive Optics”) with three lens units (LU).
SCAO is required for the correction of atmospheric distortions of the Extremely Large Telescope (ELT). METIS will offer diffraction-limited imaging, low and medium-resolution slit spectroscopy and coronagraphy for high contrast imaging as well as high-resolution integral field spectroscopy.
Client: Max-Planck-Institut für Astronomie MPIA, Heidelberg/im Auftrag der Europäischen Südsternwarte (ESO)
Contact:
Dr.-Ing. Kai Rickens
Tel.: +49 421 218 51160
E-Mail: rickens@iwt.uni-bremen.de
