Fraunhofer Institute for Production Technology IPT
Fraunhofer Institute for Production Technology IPT
© Fraunhofer IPT

Molding tools in large size

Large-area molds enable the efficient production of large optical components. These are often used in lighting applications.

© Fraunhofer IPT

Large area manufacturing of master tools

Microscopic structures on a large surface

For the production of microstructures, there are various machining processes that can be used to functionalize surfaces for optical, microfluidic or medical technology applications. For example, they can produce mold inserts for large-area retroreflectors or lab-on-a-disc platforms.

Special purpose machine from Fraunhofer IPT: Planing machine creates small structures on a large area

In most cases, the size of the machining area on ultra-precision machines is severely limited by the machine kinematics. At Fraunhofer IPT, we have developed a machine concept that allows surfaces up to 800 mm x 1200 mm to be machined: Fraunhofer IPT's ultra-precision planer is a hydrostatic ultra-precision machine with a granite bed and portal. It has three linear axes (x, y, z) and a rotary machine table with a rotary axis (c). In the future, it will be upgraded with another a axis. Only a few production machines of this type have an axis system with such large traverse paths.

Planing and fly-cutting of non-ferrous metals using diamond tools for high-precision applications.

Planing and fly-cutting processes are used to machine non-ferrous materials such as copper, aluminum, nickel silver and nickel phosphorus with a monocrystalline diamond. Different structures can thus be introduced into the surface of the workpiece. So-called V-grooves are often produced for optical applications, but other structures, such as pyramids, can also be manufactured using fly-cut or planing processes. By using special contour tools, cylindrical or non-cylindrical trapezoidal grooves can also be cut.

Manufacturing technologies for large-area mold inserts

Fly-cutting

In fly-cutting, cutting tools rotate in a linear guided motion on the surface of the component. In contrast to the diamond turning process, the workpiece is machined with interrupted cuts in fly cutting. This creates a constant surface quality with roughness in the nanometer range. With the fly-cutting process, for example, large-area pyramid-shaped structures with optical surface quality can be produced in a way gentle on the tool.

Planing

Planing is a machining process with a geometrically defined cutting edge. The component is guided in feed movements perpendicular to the cutting direction. In this way, a high optical quality below 10 nm Ra can be achieved. Mostly, components with symmetrical, sharp-edged geometries are processed this way.  Direct structuring of a product – for example, a prototypical light-scattering panel – is also possible with the planing process.

Application fields for large-area machining

 

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Optical applications

Zu den klassischen optischen Anwendungen, bei denen zerspanende Verfahren wie Hobeln oder Fly-Cutting für die Herstellung der Formwerkzeuge zum Einsatz kommen, gehören Vorsatzoptiken, Lichtleiter, Retroreflektoren und Head-up-Displays.

Optical applications
 

Microfluidics

Lab-on-disc or lab-on-chip systems are often based on plastic carrier substrates that are duplicated in injection molding processes. During the production of the master mold, channel structures in the micrometer range are introduced by micromilling and planing processes.

Microfluidics
 

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Medical technology

Micro- and nanostructures can be used to functionalize surfaces so that they stimulate cell growth, for example, or in turn achieve antimicrobial effects.

Medical Technology