Ninety-degree milling: Part 2- The endmill-type

International Metalworking News for Asia presents the second part of Sandvik Coroman's full-length article on ninety-degree milling, which was first featured in the magazine's August issue, to help provide solutions to a multitude of metalworking operations manufacturers in Asia perform.
The endmill-type of square-shoulder cutter (390) is more versatile and that the rhomboidal inserts provide long cutting edges and a wide range of insert radii, from small (0.2mm) to quite large (6.4mm) with tailor-made possibilities, which not only gives the cutter great scope in adapting the cutter to component features but also optimises tool-life and edge security. A choice of insert radii lends the cutter to wide performance optimisations in minimising vibrations and maximising feed per tooth.
The cutter has become established as a benchmark endmill, being suitable more for somewhat complex operations. It can also perform straightforward square shoulder milling, as well as being well suited to ramping and helical milling. The versatility of this cutter has given it a reserved place in most machining centres and multi-task machines as it is also suited to slot-, plunge- and peck-milling as well as facemilling, especially in the 20 to 32mm cutter-diameter range.
The standing, rhomboidal-shaped, two edge, inserts provides the cutter with the space to have more than one insert in small-diameter cutters, giving it a performance advantage. It also means that a long, double-curved cutting edge with very good chip control and light-cutting characteristics can be incorporated. It is an ideal cutter for when repeated radial passes have to be made and even for point-milling as a toroid-cutter on profiles in five-axis applications.
Milling a curved surface is a method of machining which is well suited in many modern CNC-machines where the rotating cutter machines a workpiece that is rotating round its centre and the cylindrical surface is formed as the cutter is fed radially. As such, turn milling is particularly useful when component shapes differing from those associated with conventional milling and turning are part of the component design.
Various cutter-types can perform turn milling, some better than others, and it is here that this ninety-degree endmill is suitable in roughing to finishing with a good metal removal rate. It can be equipped with a dedicated flat wiper-insert to generate straight-line contact to the machined surface and thereby producing good surface-flatness. Also, thanks to the large depth of cut capability, it is also advantageous when a shoulder has to be made. With the ninety-degree endmill, turn milling is performed using one or more dedicated wiper-inserts.
With three different insert sizes, providing a depth of cut capability of up to 15.7 mm, optimisation from light to heavy cuts can be performed in finishing, semi-finishing to roughing. With the option of vibration-damped tool-bodies and superior chip formation, the endmill-type cutter is well suited for repeated radial milling on wide shoulders or edges.  

The insert concept is also used in a long-edge cutter. Having the largest range of insert geometries, grades and radii allows it to optimise endmilling in the majority of workpiece materials.  

The face-mill type

The face-mill type of square-shoulder type cutter (490) is to usually part of set-ups in the growing nuAdidas Ultra Boost 3.0 Cny