Automotive Gear Hardened Steel Finishing: Composite Brazed CBN Inserts for Higher Efficiency and Longer Tool Life

Performance Comparison Under the Same Application Conditions

Project Challenge

The coupling gear required final dimensional control after carburizing and hardening. In continuous finishing, the customer’s previous CBN inserts showed surface marks during small-depth cutting, increasing dimensional variation over extended runs. Limited edge life also led to frequent insert changes, disrupting the production rhythm of the automated CNC line and adding maintenance pressure.

Composite Brazed CBN Insert Solution

UHD Ultrahard Tools combined insert design and process parameter optimization rather than treating tool selection as an isolated variable. The UPN605 C06 uses a composite brazed structure that combines a carbide substrate with a CBN cutting layer, supporting edge wear resistance and thermal stability for continuous hardened-steel finishing.

• Geometry for small allowance finishing: the cutting edge was matched to the 0.1 mm depth of cut to support smoother cutting and reduce the risk of surface marks.
• Controlled brazing consistency: stable tip positioning and angle control helped reduce variation between inserts, an important factor for automated machining.
• Coordinated cutting parameters: the process was optimized for dry cutting at 160 m/min while maintaining a stable finishing rhythm.

Application Value for Automated Gear Production

In production, the solution helped reduce visible surface marks and made dimensional behavior more consistent across batches. Longer tool life reduced changeover frequency, while the shorter cycle time supported a more predictable automated line. For automotive transmission gear machining, the case demonstrates that insert consistency, edge design and cutting parameters should be evaluated together when improving hardened steel finishing performance.

Reusable Experience for Similar Hardened Steel Applications

For hardened automotive gears, bearings, wind power transmission components and other high-hardness precision parts, small-allowance finishing requires more than high wear resistance. A CBN insert solution should also support controlled cutting behavior, repeatable tool geometry and reliable performance in continuous operation. This composite brazed CBN approach provides a practical reference for manufacturers seeking clearer process control and more stable automated precision cutting.