The rotary tool can be driven so as to rotate about a rotational axis and encompasses a cutting area, which is formed by the cutting bodies and which is geometrically undefined, or a geometrically defined tool blade. The rotary tool comprising cutting bodies, which form a geometrically undefined blade area, can be a grinding wheel or a dressing tool, for example. Tools, the cutting bodies of which form a geometrically defined tool blade, are milling, drilling or grinding tools, for example.
In particular in the case of precision tools, it is important that a highly accurate profile and a highly accurate concentricity or axial run-out, respectively, of the rotary tool, is attained. Due to the fact that machining accuracies of a few micrometers are to be reached by means of the tool, the appearance of wear or an inaccurate production of the rotary tool can lead to inadmissible tolerance deviations. The accurate production or finishing of the rotary tool is difficult, in particular when the cutting bodies consist of a very hard material or encompass a very hard outer wear-resistant layer, for example if materials, such as cubic crystalline boron nitride, diamond, polycrystalline diamond (PCD) or diamond layers, which are removed in the CVD process (chemical-vapor-deposition method), are used. Such cutting bodies are expensive and the finishing is time-consuming and cost-extensive, so that the machining of the rotary tool is to take place with a material usage of the cutting bodies, which is as low as possible. On the other hand, however, the target dimensions of the rotary tool must be reached.
DE 32 02 697 C2 proposes the use of an electron or laser beam, which is oriented tangentially to the outer surface of the tool, for machining a rotary tool. Crystal tips of the cutting bodies, which stick out from a specified target enveloping area, which specifies the outer contour of the rotary tool, are cut off. The rotary tool is rotated for this purpose, while the laser beam moves along the cross sectional contour, so that the rotary tool is to finally obtain the desired contour.
It turned out, however, that a tangential focusing of the laser beam towards a rotating rotary tool is unsuitable for the machining thereof, because the laser beam can only be focused at a certain point. Due to the fact that the laser beam must move along the entire tool contour in this manner, the method is furthermore extremely time-consuming. The rotary tool is furthermore machined only with reference to its contour. In addition, cutting off the tips of the cutting bodies, which stick out from the target enveloping area, creates relatively large tangential surfaces, which reduce the cutting effect of the rotary tool.
A further known possibility for finishing a rotary tool, which is used for grinding, is the so-called “crushing”. In response to the crushing, the working surface, which is provided with the cutting bodies, is machined two-dimensionally by means of a tool, so as to adapt the actual enveloping surface to the target enveloping area. In the area of the machined surface, cutting bodies are thereby broken out of the binding material by means of a crushing tool. This method, however, is limited to the accuracy of the crushing tool and is not suitable for all types of the rotary tools, which are to be machined. In addition, the crushing requires a porous or rough binding material, because the cutting bodies can otherwise not be broken out. It cannot be used in many cases.
Known abrasive methods for sharpening or finishing such a rotary tools also have the disadvantage that the sharp tips and edges of the cutting bodies are removed and that the cutting effect of the rotary tool is therefore influenced negatively.
USPTO Backgrounds
USPTO Backgrounds