Sumitomo develops ACE Coat AC810P inserts for challenging continuous turning

AC810P inserts have an ultra-hard CVD applied Super FF titanium carbonitride (TiCN) coating of thickened and toughened Aluminia for a 30% increase in hardness. The inserts also incorporate Sumitomo's latest NME chip breaker development in addition to well-proven NSE, NSEW and NGE styles used with the company's other turning inserts. The Super FF coating uses ultra-fine crystals to provide a homogenous and extremely dense structure that enables an ultra-smooth surface finish to be created on the insert that also benefits coating strength and adhesion. As a result, the coating provides improved resistance to peeling, cracking, chipping and wear when the inserts are used at cutting speeds over 300 m/min on carbon, alloyed and stainless steels, as well as cast iron. According to Sumitomo, from data provided by customers involved with high speed turning, it was concluded that more than half of damaged or failed inserts were due to crater wear. Crater wear is a consequence of chip flow eroding the rake face of the insert which reduces the toughness of the cutting edge, as well as lowering the hardness of the carbide substrate and ceramic coating. Crater wear is not only influenced by the grade of the turning insert but also by the geometry of the chip breaker. Sumitomo now offers four 'E'-type chip breaker styles on AC810P inserts, the latest NME for roughing which creates a very smooth chip flow, NSE for finishing, NSEW for high efficiency finishing and NGE for more general purpose turning. NME has a dimpled surface which helps to control thermal elevation and a 4º primary ridge with a wide yet shallow breaker geometry that improves control of the chip and its ejection from the cutting zone. NSE has a wave shaped cutting edge with a 5º primary ridge on the top rake to help control chip flow, giving stable chip management in a wide range of processes and a side ridge to reduce any stress concentration and rake face damage. The NSEW profile improves a 'wiper' effect and enables high feed conditions without any compromise to surface finish, says Sumitomo. Meanwhile, NGE has a 3º primary ridge and smooth curved rake face which reduces stress when roughing at high speed and using a heavier depth of cut. All inserts are coloured gold for easy identification of cutting edge wear. ACE Coat AC810P inserts with the latest 'E'-type chipbreakers can be used for between 1 and 6 mm depth of cut and run at feedrates between 0.1 and 0.7 mm/rev. Inserts are available in 55 and 80º deg diamond, square and triangular styles as well as 80º Trigon.