When Sandvik Coromant released a video in support of its new PrimeTurning™ turning technology, the video almost appeared to be going in reverse. The cutting tool traversing from chuck to the end of the workpiece. Had it been going in reverse, however, material would have magically gone back on the blank, as opposed to the long strips of material being removed first along one axis and then another.
PrimeTurning is a new turning method that enables turning in all directions. Unlike conventional turning operations, PrimeTurning allows machine shops, OEMs and other users to complete longitudinal facing and profiling operations with a single tool. In addition to the prime turning technology, the company released two types of tooling, an A-type for fine finishing and a B-type for roughing applications.
With this forward-and-back cutting capability, and its innovative tooling technology, Sandvik Coromant believes that some applications could achieve productivity increases of more than 50% as compared to conventional techniques.
For instance, Cutting Tool Engineering magazine reported on an Italian manufacturer who reduced the cycle time for machining a shaft from 2.42 to 1.36 minutes and extended the tool life per edge from four pieces to nine by using the PrimeTurning system.
According to the report, a competitor’s conventional insert ran at a cutting speed of 150 m/min., a feed rate of 0.012 ipr, and a DOC of 0.079 in. By contrast, the CoroTurn® Prime B-type roughing insert ran at double the cutting speed and DOC, and a feed of 0.032 ipr when turning forged, ASTM B564 nickel alloy with a hardness of 250 HB.
Major reasons for the reported success of the PrimeTurning technology is due to the small entering angle relative to the feed direction, as well as a higher lead angle that allows the user to cut substantially faster. The turning operation creates thinner, wider chips that spread the load and heat away from the nose radius. In addition, as cutting is performed in the direction moving away from the shoulder, there is no danger of chip jamming, which can occur if chips are pushed against the shoulder during turning.
|Entering and lead angles:|
|A-type KAPR = 30°, PSIR = 60°|
|B-type KAPR = 25°, PSIR = 65°|
“Experienced operators know that a small entering angle allows for increased feed rates,” said Håkan Ericksson, Global Product Specialist at Sandvik Coromant. “However, in conventional turning they are restricted to using entering angles of around 90 degrees to reach the shoulder and avoid the long, curved chips that a small entering angle characteristically delivers. PrimeTurning solves these problems by combining a perfect reach at the shoulder and the application of 25 degrees to 30 degrees entering angles with excellent chip control and maintained tolerances. This innovation presents countless possibilities to perform turning operations in much more efficient and productive ways. It’s not just a new tool, but a totally new way of turning.”
PrimeTurning is supported by the introduction of two dedicated CoroTurn Prime turning tools, part of the CoroTurn insert tooling line, and the PrimeTurning code generator, which supplies optimized programming codes and techniques.
The new turning tools include:
- The CoroTurn Prime A-type tool with three 35° corners designed for light roughing, finishing and profiling.
- The CoroTurn Prime B-type tool with strong corners designed for rough machining.
Suitable for ISO P (steel), S (heat-resistant super alloys and titanium) and M (stainless steel) category materials, nine CoroTurn Prime A-type and six CoroTurn Prime B-type inserts are currently available, with expansion to other materials envisioned for the future. The inserts are supported by 52 variants of tool holder, including Coromant Capto®, CoroTurn QS and shanks.
The CoroTurn Prime inserts feature three edges per corner. One edge each for longitudinal, facing and profiling thus distributing the wear over a longer edge and not just the insert tip. It also moves heat away from the cutting zone that helps inserts last substantially longer.
Sanvik Coromant also developed a Code Generator to develop specialized toolpath strategies and take full advantage of CoroTurn Prime insert design. The generator supplies programming codes and techniques to set up maximum parameters and variables for a particular application to secure maximum output in ISO P steels, ISO M stainless steels and ISO S heat-resistant super alloy (HRSA) materials.