Designed to machine bores in demanding, highly alloyed materials from 0.2 mm diameter to 6.8 mm diameter, standard lengths for the new EG35 grade are from five times diameter at the smaller end of the range to a maximum of 35 mm.
The carbide inserts feature a new coating, substrate and microgeometry. During development of the new tool, a performance increase of 30% was achieved solely by modifying the substrate and keeping the coating and insert microgeometry the same. Horn then found that a sharper cutting edge resulted in higher metal removal rate and less cutting pressure. Although mechanical stress on the edge was elevated, the tougher substrate was able to cope.
A new coating system was devised, tailored to the combination of the tough substrate and the more durable cutting edge. It allows a denser layer of TiAlN (titanium-aluminium-nitride) with a more homogeneous structure to be deposited that has excellent adhesion and improved smoothness. The enhanced anti-friction properties mean that less heat is transferred to the tool, so the cutting edge is exposed to lower thermal stress.
High performance 105 Supermini tool life comparisons with existing substrates and coatings were carried out by Horn during extensive pre-launch trials. Results showed that using the new EG35 grade on cobalt-chrome, a popular alloy used in the medical sector, tool life was increased by as much as 60%. In the case of carbon steel, tool life more than doubled and when tests were carried out machining tool steel, the tool life increase compared to competitors’ inserts was even greater.
The Supermini system offers more than 1,500 insert types for a host of different applications. Right- and left-hand versions can be used in one standard Horn Supermini toolholder, available with or without internal cooling.
