It features an unconventional insert inclination angle, which is designed to provide a large positive angle on the main cutting edge, leading to excellent chip formation, a smooth, soft sound and low cutting forces.
CoroMill 745 has been developed for roughing to semi-finishing operations on steel and cast iron workpieces (ISO P and ISO K materials). The upshot of deploying this double-sided, multi-edge cutter is that production economy and cost-per-component can be improved considerably.
In essence, the positive cutting action mirrors that of a singlesided concept face mill, but with the new cutter there are cutting edges on both sides of the insert. With 14 cutting edges available, face milling operations up to 5.2 mm (0.205”) maximum depth of cut are expected to benefit.
CoroMill 745 inserts are purposely thick and secure with strong, sharp edges for high precision and a robust cutting process, while the precision ground geometries are designed to avoid workpiece frittering in cast iron, which can often occur at the cutter exit side of the component.
The insert position and heptagonal (seven-cornered) insert shape make for easy replacement and indexing in line with modern time saving and ‘green light’ machining demands. Indexing, in fact, can be performed without operators having to remove their gloves. In effect, the insert position can be secured before tightening the large M7 screw (deployed for extra process reliability). As a further benefit, due to the large screw hole, less powder is used in the insert manufacturing process, thus benefiting the environment.
Another useful feature for production engineers is the availability of a differential pitch (MD pitch) up to 160 mm (6”) diameter for roughing operations where reduced vibration is essential. This medium pitch MD design was developed using genetic algorithms to reduce vibration when machining components that are sensitive to resonance or reverberation. Here, the insert position is compensated radially for an even chip load.
In terms of insert geometries, Sandvik Coromant is initially introducing the E-M30 and E-M50 types for CoroMill 745, where E-M30 is the choice for steel and cast iron workpieces, as well as in vibration sensitive operations and when less power consumption is required.
Conversely, E-M50 is a tougher geometry for more demanding operations or when higher productivity is needed. E-M50 should also be selected for grey cast iron (GCI) workpieces found commonly in numerous automotive applications, as well as in nodular cast iron (NCI) machining.
Arbor, Coromant Capto and CIS arbor coupling variants can be used, with through-coolant in cutters up to 160 mm (6”) diameter. All CoroMill 745 milling cutter bodies offer an entering angle of 42°, although among future planned additions to the range is a high-feed variant featuring a 25° lead angle, which will offer feed rates of up to 0.7 mm/tooth (0.028”/tooth).
APMEN Sept 2016, Product Highlights