Hard turning grades enhance speed and toughness

Proven to reduce machining time and costs by 70% or more, hard part turning in comparison with conventional grinding techniques, also offers improved flexibility, better lead-times and higher quality.

However, these gains can only be realised using optimised insert grades.With CB7105, Sandvik Coromant has created a grade for hard part turning that offers enhanced crater wear resistance in comparison with existing solutions, while CB7115 is designed to provide users with better fracture resistance than today’s available grades. These benefits equate to higher speed and improved edge line toughness respectively.

Hard part turning is usually a finishing or semi-finishing process where typical machining challenges include high surface and dimensional tolerance demands, along with competitive tool life. CB7105 and CB7115 have been developed to tackle these challenges through the application of a high performing PCBN grade material and coating, as well as appropriately adjusted edge preparation on the inserts. In combination with high quality control during insert manufacturing, this results in a number of end user benefits.

Torbjörn Ågren, Product Manager Turningat Sandvik Coromant commented: “CB7105 allows machine shops to achieve lower cost per part when used as part of a high speed machining strategy.”

Ågren added: “Alternatively, users of this grade can benefit from longer tool life at lower speeds. CB7115 is also designed to deliver lower cost per component, typically though the adoption of one-cut strategies at higher speeds.”

A case in point saw one trial site increase production of case-hardened 16MnCrS5 (HRc 57-62) automotive components by at least 15% after switching to CB7105 and CB7115. In fact, CB7115 surpassed 600 components (at 0.15 minutes time-in-cut) with predictable surface generation and lower Rz value. The cutting speed was 170m/min (557ft/min), while feed rate was 0.22mm/rev (0.087”/rev) with a cutting depth of 0.15mm (0.059”).

Ultimately, reliable and predictable machining is always the aim when it comes to machining case-hardened or induction-hardened steel components such as transmission shafts and gears. CB7105 and CB7115 offers updated PCBN material, edge preparations and improved edge line quality to ensure better and more predictable tool life and edge line security.