Sumitomo tailors ACE Coat AC630M insert for tough rough turning
1 min read
Sumitomo has tailored its ACE Coat AC630M carbide grade insert for rough turning stainless steels and it can also handle partial interrupted cutting cycles. The insert combines a sharp cutting edge geometry with a chip-resisting coating grade that is also able to eliminate the generation of chatter marks on small diameter machining cycles and prevent built-up edge which can be created when slower cutting speeds are employed.
Stainless steels are difficult to machine and have low thermal levels of conductivity. This can cause plastic deformation and components can easily become work hardened as they are processed which further increases the load on the cutting tool. Sumitomo says the smooth Super FF coating helps to overcome these problems while also improving chip flow and preventing any degradation of the insert through 'notching'.
The Super FF Alumina coating is a 5 micron multi-layer of fine grain TiCN on a AC600M cemented carbide substrate which helps to resist any tendency for surface peeling from the substrate. The micrograin Alpha-Al2O3 outside coating creates a highly polished insert face and cutting edge that helps to resist heat, wear and chip adhesion.
There are two chipbreaker styles for roughing tasks. NMP is for use on lower power machine tools and NMU is for medium to heavy roughing cycles. NMP can be run at between 2 and 6 mm depth of cut and between 0.2 and 0.6 mm/rev feedrate, while NMU can be applied up to 10 mm depth of cut between 0.4 and 0.8 mm/rev feed.
Recommended cutting speeds on free machining stainless steels are 155 to 235 m/min and 140 to 210 m/min for ferritic and martensitic stainless steels. More difficult to machine stainless steels can be cut at 120 to 180 m/min while tougher austenitic stainless steels between 95 and 145 m/min. Duplex materials can be machined at between 70 and 110 m/min.
Inserts are available in negative styles, which include diamond, square, triangular and trigon, while positive styles available in the Sumitomo AC630M insert range include diamond, square and triangular.
