Chesterfield-based Dormer Pramet (www.dormerpramet.com) has launched several new inserts and a grade to support the turning of specific materials.

The new chip-breakers — developed under the company’s Pramet brand — target finishing and medium-to-rough turning operations in steels, cast irons, high-temperature alloys and stainless steels.

The NF1 and NF2 positive chip-breakers, which are for stainless-steel turning, are shaped to provide good chip control and low cutting forces, thereby ensuring high levels of durability and productivity.

NF1 is a universal chip-breaker for finish machining to medium-duty machining, and is peripherally ground to provide a good surface finish, while NF2 incorporates a small ‘stabilising’ T-Land and covers a range of applications from semi-finishing to light roughing.

Dormer Pramet says that its FF2, FM2 and RM3 inserts for steel and cast-iron machining provide good chip control at low feeds and depths of cut while ensuring a high-quality surface finish.

The FF2 chip-breaker has a positive rake angle and accommodates depths of cut of about 0.15mm for fine-finishing applications in low-carbon steels; FM2 is for finish machining to medium-duty machining with depths of cut from 0.2mm.

Featuring a protective land, it is suitable for continuous and interrupted operations. The RM3 chip-breaker is designed for roughing applications in steels and is said to be suitable for use in unfavourable machining conditions.

Finally, Pramet’s SF2 and SF3 positive inserts are aimed at turning applications in high-temperature alloys. The SF2 chip-breaker is capable of fine turning at low feeds, while the SF3, with its positive inclined cutting edge, supports finishing operations.

Claimed to be especially effective on small and slender components, both inserts feature a sharp cutting edge with minimal radius. This ensures low cutting forces, which in turn prevent work-hardening and ensure a good surface finish.

In a further development, Dormer Pramet has introduced a grade for turning stainless steels. T7325 has been designed to complement the existing T7335 grade, which is recommended for use in unstable machining environments.

Also suitable for interrupted cutting, the T7325 grade features a ‘functional gradient substrate’ and special MT-CVD coating. This combination is said to offer high cutting strength, reduced built-up edge and resistance to the formation of cracks.