According to Princes Risborough-based Sumitomo Electric Hardmetal Ltd, key to the capability of the Sumi Dual Mill TSX series of high-efficiency 90deg shoulder mills is the combination of fine carbide insert-sintering technology with precision profile grinding (www.sumitomotool.com).

This enables the periphery-ground inserts, when used with the new design of tangential cutter body (available in standard, medium and fine-pitch versions), to achieve high levels of surface finish.

The tangentially mounted carbide inserts offer a choice of chip-breakers: L for low-rigidity machine set-ups; G for general-purpose operations; and H for where a stronger insert edge is required to support tasks such as roughing, heavy interrupted cutting and hard-steel milling, for example.

Sumitomo’s TSX shoulder mills comprise shell-type bodies between 40 and 160mm in diameter, plus shank-type bodies between 16 and 160mm in diameter; they are designed to undertake operations such as face and shoulder milling, slot milling, and side and face milling.

Two sizes of precision-ground insert — each with four corners — accommodate 8 or 12mm depths of cut. Moreover, a range of grades is available.

Sumitomo’s P-class ACP100 grade, which is for machining carbon steels and alloy steels, features a tough carbide substrate with a thin-layer Super FF coating that is resistant to cracking and wear when undertaking high-speed milling.

ACP200 is for general machining — including die steels — and features Sumitomo’s multi-layered Super ZX coating, which is said to offer high levels of resistance to fracture and wear.

ACP300 comes with the same coating but applied to a tougher substrate, making it suitable for interrupted cutting.

Sumitomo’s M-class ACM200 grade has a hard FF coating for hard-machining applications, while ACM300 with its Super ZX coating ensures a good balance between wear and fracture resistance.

Configured for machining cast irons and ductile irons, Sumitomo’s K-class ACK200 features a Super FF coating on a tough carbide substrate, giving it good thermal and wear characteristics.

Finally, ACK300 with Super ZX coating will accommodate interrupted cutting applications.

A recent customer trial based on milling a workpiece made from 42CrMo4 alloy steel used a TSX shell cutter body combined with ACP200 grade inserts and G-type chip-breaker.

The test (with coolant) was run at a cutting speed of 270m/min, a feed of 0.05mm/rev feed and an 8mm depth of cut.

The Sumitomo set-up not only improved component quality but also increased the number of parts produced per insert from 135 to 220.