3D Technology in CBN – a new dimension of internal grinding?
Reduced bore diameters on workpieces, materials which are difficult to machine as well as increasingly tighter tolerances in the precision machining of bores call for new concepts in terms of the design of abrasive tools. The well-known great features of vitrified bonded CBN abrasive tools, the optimised CBN crystal types, hardness and porosity, as well as the complementary dressing technology are starting to be stretched to their limits here.
The combination of a new innovative production procedure as the basis for designing the required structures, as well as a new conceptual approach when it comes to designing the structure, make big advancements for a small bore.
Generally speaking, the 3D technology provides a highly porous tool concept, which optimises the following factors in terms of the previously unknown variability:
- Pore volume up to 60%
- Pore radius distribution – 5 - 10 x larger than the abrasive grain
- Wear resistance – at least the same value as the current standard
- Use of very fine CBN grit sizes with a simultaneously high material removal rate
In practice, the current state of the art technology results in a significant reduction to grinding forces and thus deflection of the internal grinding quills, which allows considerable improvement to the geometries on the workpiece. Nevertheless, at the same time, no compromises must be made where wear resistance is concerned.