About cutting edge forms
Different cutting edges are suited for different materials and machining steps.
RADIUS CUTTERS
Radius cutters have a semi-circular rounded tip. Depending on their size, they are used for roughing, finely finishing or carving out fissures. They can also reach undercuts. For machining glass ceramics and composites, radius grinding tools are used (beside torus grinding tools).
FLAT CUTTERS
Depending on their size, these tools are used for milling 90° angles and smooth edges as well as roughing PMMA and wax.
TORUS CUTTERS
For machining glass ceramics and composites, torus grinding tools are used (beside radius grinding tools).
Radius cutters
The dental radius cutter has a semicircular rounded tip. It is available with cutting-edge diameters of 0.3 mm to 2.0 mm. While the 2.0 mm tool is mainly used for efficient roughing, tools with a small diameter of 0.3 or 0.6 mm are mainly used for finely finishing or carving out fissures. Due to the especially long free grinding of these tools, undercuts can also be reached easily.
Depending on their field of application, the radius cutters have one to four cutting edges: for PMMA and wax, there are, for instance, extremely sharp single-tooth cutters available with a very low tendency to clog. On the other hand, the 2 mm cutters for the abrasive zirconia have three cutting edges and the CoCr cutters even have four in order to reduce the wear for each cutting edge and to ensure greater process reliability.
Grinding tools
For machining glass ceramics and composites, vhf offers torus and radius grinding tools with a diamond grit in different grain sizes. The two smaller torus grinding tools with their fine grain size are mainly used for drillings and abutments. The 2.4 mm grinding tools with their coarser grain size are used for roughing and the fine-grained radius grinding tools for the finishing process.
All tools are characterized by their good abrasion and break resistance and extremely long endurance. The diamond grit with its especially good binding to the shank avoids micro-cracks and reduces the sensitivity to thermal impact.
Cylindrical cutters
Cylindrical single tooth cutter
The cutting edge of this cutter with flat face grinding is extremely sharp and faceted. Milled edges are very smooth even at high feed rates and the risk of clogging is very low – even for plastics.
This tool is available with a cutting-edge diameter of 2.5 mm; it is exclusively used for roughing PMMA and wax. Roughing with a flat ground cutter reduces the milling time.
Cylindric double tooth cutter
A double-tooth cutter with flat face grinding and a cutting-edge diameter of 1.2 mm. It is used when 90° angles have to be milled, e.g. in drillings and abutments.
For machining non-precious alloys on a cobalt-chrome basis and titanium, this tool is available as a torus cutter with a small edge radius which protects the cutting edges (only 1.2 mm diameter) – so a higher endurance is guaranteed.
