For many years, the diamond-coated milling tools for granite and abrasive materials KARAT I and KARAT plus were regarded as groundbreaking, especially in tool and mold making. With a further development, which Schreurs in Kernen calls Evolution, the company now intends to continue setting the standards in this field with KARAT II. Two years ago, the company therefore began to further develop and optimize the cutting edge, the coating, and the radius and diameter tolerances. With success, as it turns out, because with the currently optimized cutting edge geometry in combination with a new solid carbide, at least 25% higher machining speeds (fz) are possible.
In internal tests as well as with customers who already have these tools in use, graphite was milled with a KARAT II, ⌀ 10mm and a feed rate of over 8m/min. The optimized diamond coating of the new KARAT II series was developed jointly in close cooperation with one of the world's leading manufacturers of PCD, CVD and diamond coatings. Schreurs estimates the increase in tool life to be approximately 33% compared to similar well-known market competitors.
And Kernen has also made considerable progress in terms of tolerances. Radius and diameter tolerances have again been significantly improved. Every tool that leaves production is measured by laser and marked with exact diameter and concentricity. This was already the case with KARAT I, but with KARAT II Schreurs goes one step further. In addition, customers receive tools within a tolerance band of 10 µm. In the case of ball nose end mills, where radii exceed half the diameter, the envelope plus radius and diameter are also toleranced. This narrow tolerance band has thus enabled the tools to be optimized specifically for automation.
However, another not insignificant aspect of the new tool series is the fact that the tools are interoperable with the common tools of the well-known manufacturers. This means that the taper angle to the shank has been selected in such a way that there is no additional programming effort on the part of the customer when using the tools.
In summary, Schreurs describes the advantages of the Evolution KARAT II with significant improvements in terms of process reliability, tool life, surface finishes including higher cutting performance. In addition to the special dimensions, the new KARAT II series has so far been offered in two lines: double-edged torus and ball nose end mills in the standard version, with radius tolerances of minus 5 µm and in diameters from 0 to 10 µm.