Five different grades of RDMT button-style indexable inserts for milling carbon steels, alloy steels and stainless steels, as well as cast iron, have been added to the milling portfolio of Princes Risborough-based Sumitomo Electric Hardmetal Ltd (www.sumitomotool.com).

The inserts are said to be advantageous in applications where high resistance to wear and insert fracturing is required.

Available in sizes of 8, 10, 12 and 16mm (inscribed circle), the five grades cover PVD-coated ACP100, 200 and 300, and CVD-coated ACK200 and 300 variants.

The ACP100 grade for milling steel and ACK200 for cast iron incorporate Sumitomo’s Super FF coating, which the company says provides up to 1.5-times greater machining efficiency and gives more than double the tool life of conventional grades under normal cutting conditions.

Chipping resistance and adhesion strength are also said to be enhanced.

Similarly, the ACP200 and 300 grades for milling steel and ACK300 for cast iron feature Sumitomo’s Super ZX multi-layer nano-technology coating, which combines alternating 10nm layers of TiALN and AlCrN to deliver benefits matching those of Super FF.

The ACP200 is suitable for the general milling of steel and die steels, while ACP300 is recommended for the interrupted machining of stainless-steel workpieces.

Meanwhile, ACK300 has been developed for the general and interrupted milling of cast and ductile irons. In a recent milling demonstration on die steel, the Sumitomo ACP200 grade increased the number of workpieces completed from 300 to 400, says the company.

The machine was run at 150m/min, with a feed rate of 0.3mm/tooth and a 3mm depth of cut.