Sumitomo’s latest ACE Coat AC405K and AC415K turning s can demonstrate extended in-cut life of up to 1.5 times greater than conventional grades of s even when using the improved cutting speed and more efficient machining capability when semi-finishing and finish turning nodular graphite cast irons now widely used in the automotive sector.
According to Sumitomo Electric Hardmetal based in Princes Risborough, both new grades meet the latest criteria for cast iron machining giving a very stable performance over extended durations of production. These can even include interrupted cutting cycles which can be extremely demanding on machine and tooling.
Indeed, ACE Coat AC405K has been developed for high speed applications at up to 570 m/min when continuous turning nodular cast iron and ACE Coat AC415K for general turning, at up to 400 m/min, which can also include continuous and interrupted cuts.
Over recent years the use of nodular cast iron, which is highly ductile, has been adopted in preference to grey cast iron especially in the automotive sector to enable thinner, lighter castings to be used and contribute to improvements in fuel efficiency. However, for machinists the nodular material is more arduous to cut and when cost-per-part is an important consideration, higher spindle utilisation and consistent and predictable performance from cutting tools is a priority that Sumitomo has strived to maintain.
Both AC grades are coated with Sumitomo’s ultra-hard, multi-layer chemical vapour deposition (CVD) Super FF coating. This recently developed coating incorporates a homogenous structure of ultra-fine ceramic particles which have extreme levels of density with the thin film of titanium carbonitride (TiCN) and a thickened and toughened aluminia film giving a 30 per cent increase in hardness. As a result , s with the Super FF coating can offer benefits of a 50 per cent improvement in wear resistance and any tendency of the film coating to peel back. In addition there is a good resistance to edge damage and chipping with low levels of chip adhesion (built-up edge).