Diamond-coated micro abrasive pencils

The aim: Smaller and finer. Micro abrasive pencils with bonded diamond grains are restricted to diameters above 0.1 millimeter and grain sizes larger than D 30. However, many manufacturing tasks are affording smaller diameters and finer grain sizes. Smaller structures and smoother surfaces would thus become possible. The Fraunhofer IST is developing new diamond abrasive pencils to reach these aims.

Advantages of compeDIA®-micro abrasive pencils

For conventional diamond abrasive pencils, diamond grains are bonded onto the tool by means of a binder. In contrast to this method, the compeDIA® abrasive pencils are coated without any binder in a CVD process with a continuous diamond layer. This polycrystalline compeDIA® layers have a roughness with sharp edges, that can act very powerful for grinding.

A lot of advantages can be achieved with compeDIA® layers:

  • Smaller tool diameters: 50 micrometer have been reached up to now
  • Smaller “grain sizes”: Crystal sizes down to one micrometer and less are possible
  • Complex geometries: e. g. conical, spherical or freeform geometries
  • High accuracy: even film thickness, uniform crystal height
  • Highest wear resistance by 100 percent diamond content

The diamond coating process

At Fraunhofer IST, the compeDIA® diamond coatings are deposited with a chemical vapour deposition process (CVD). A hot-filament activation is used thereby. The roughness of the grinding tools (“grain size”) can be controlled through the process parameters. As substrate material, cemented carbide is used.

Possible applications

Micro abrasive pencils are needed in many industries to solve difficult manufacturing tasks:

  • Finishing of holes in nozzles and optical components
  • Hand-operated machining in dentistry
  • Manufacturing of precision components and miniature workpieces made of glass, ceramics or cemented carbide
  • Micro mechanical systems
  • Die and mold making: Manufacturing of freeform-surfaces with small dimensions and short radiuses of curvature
  • Manufacturing of holes by applying a circular movement to the abrasive pencil or by using hollow tools

Our services

We offer the development of individual compeDIA® diamond grinding tools according to your specific manufacturing tasks. The spectrum of our services reaches from prototype coatings up to the coating of small lots. The coating equipment available at Fraunhofer IST provides a capacity of several hundred grinding pencils per lot, which is an important prerequisit for an economic production of abrasive pencils.

Our services cover not only the development of coated tools but as well the technology transfer for coating processes and plants and the support for coating in an industrial scale. In addition, we cooperate closely with research institutes that are able to test the newly developed tools in detail.