Sumitomo launches AC6000M – a new family of turning inserts and chipbreakers for stainless steel


The development team at Sumitomo Electric Hardmetal has released AC6000M, a new series of turning insert grades and three chipbreaker styles to cover roughing, semi-finishing and the finish machining of ferritic high chrome, Martensitic, austenitic, two-phase austenitic/ferritic materials as well as precipitation hardening stainless steels.

The range comprising AC6020M, AC6030M and AC6040M inserts are suitable for continuous, light interrupted and heavy interrupted cutting conditions at speeds up to 250m/min demonstrating longer in-cut tool life, high resistance to wear and chipping.  Thus they are able to create a stable machined surface compared to more conventional insert grades used on stainless steel materials.

Meanwhile, the three types of chipbreaker NEF, NEG and NEM help to manage the chipping process across the insert grades, enhance performance and reduce wear on the insert when cutting difficult materials.

AC6020M is recommended for higher speed turning of stainless steels and light interrupted cutting cycles.  This is due to the greater toughness of the substrate plus the chemical vapour deposition (CVD) boride-based titanium compound five-stage, multi-layer Absotech Platinum Technology coating.  This coating embraces an ultra-high smoothness on the surface texture coupled with low-stress.  The advantage of a very stable cutting edge linked to good coating adhesion standards creates a high resistance to chipping.

Like AC6020M inserts, AC6030M has the same Absolute Platinum Technology coating but introduces a wider range of applications so it is especially suitable for more general stainless steel machining tasks.  These can involve continuous, light interrupted or heavier interrupted cycles.  AC6030M resists the onset of flank wear when compared with more conventional grades.

For greater demands and unstable cycles such as when performing heavy interrupted turning of stainless steels, the improved fracture resistance of the exclusive Sumitomo carbide substrate used in the AC6040M grade, coupled with the newly developed Absotech Bronze TiALSiN Technology multi-level Physical Vapour Deposition (PVD) coating, means higher resistance to heat oxidation.  The ever-greater level of coating adhesion also ensures a greater resistance to peeling at speeds up to 150 m/min.

In addition to the new A6000M family of insert technology and to aid turning cycles on stainless steels, Sumitomo has developed and applied three new chipbreakers.  NEF reduces chip curling under finish cutting conditions and especially when low depths-of-cut are involved.  There is a sharp 20 deg rake angle that helps to reduce wear and the inclusion of grooves on the rake face lowers heat and further assists chip flow.

NEG is a high versatility chipbreaker that incorporates a special design of 30 deg top rake with a 0.9 mm land to aid chip management under cut and reduce the onset of wear. Crater wear is also prevented by the incorporation of a series of raised smooth round bumps on the insert.

When rough turning, NEM has a larger radius rake face that smoothly evacuates chips at between feed rates of 0.2 and 0.6 mm/rev and up to 6 mm depth-of-cut.  It also reduces wear attributed to cratering while maintaining an excellent edge strength to the insert due to the design eliminating any points of change on the cutting edge.