Following last year’s launch of PrimeTurning methodology and tools for external turning operations, Halesowen-based Sandvik Coromant (
www.sandvik.coromant.com) is introducing a dedicated CoroTurn Prime SL head that makes the process available for internal turning operations.
This head will cater for the needs of oil and gas, aerospace and other manufacturers faced with machining internal diameters in excess of 90mm and overhangs of 8-10xD.
In contrast to conventional internal turning, PrimeTurning sees the tool enter the material at the chuck end of the component and remove metal as it travels back out towards the bore exit (inside-out direction).
This direction of cut allows for the use of a small entry angle that is said to facilitate significant productivity gains. However, if required, another variant is available, with a reverse tip seat that makes it possible to perform PrimeTurning in the opposite (conventional) direction.
There are two insert types for internal PrimeTurning: A-type for profiling, finishing and light roughing; and B-type for roughing and finishing operations.
According to Sandvik Coromant, speed and feed rates can effectively be doubled with PrimeTurning, largely because the small entering angle and higher lead angle create thinner, wider chips that spread the load and heat away from the nose radius, resulting in increased cutting data and/or tool life.
Furthermore, as cutting is performed in the direction moving away from the shoulder, there is no danger of chip jamming, which is a common effect of conventional internal turning.
With CoroTurn Prime SL heads, customers can create a wide range of tool combinations from a small inventory of adaptors and cutting heads.
SL heads feature a 40mm diameter and are available as solid-steel bars and carbide bars, as well as Silent Tools damped boring bars.
In a further development, Sandvik Coromant now offers its new H3 geometry to eliminate any concerns about chip control, which can be challenging when machining low-carbon and high-strength steels.
The H3 geometry is available for B-type inserts in grades GC4325, GC1115 and H13A.