Automotive transmission coupling gears require stable final machining after carburizing and hardening. For 16MnCr5 hardened steel at HRC 58–62, small‑allowance finishing must control surface quality and dimensional stability while maintaining a predictable cycle time on automated production lines.
UHD, the brand of Henan UHD Ultrahard Tools Co., Ltd, developed a composite brazed CBN nnsert solution for continuous dry finishing of gear bores and end faces. In this application, the UHD UPN605 C06 Composite Brazed CBN Insert supports finishing at 160 m/min with a 0.1 mm depth of cut, helping reduce tool marks, dimensional variation, and tool‑change frequency.
Transmission coupling gears are critical drivetrain components. After heat treatment, their final dimensions and surface condition are completed through precision machining. In automated CNC turning cells or linked production lines, even minor variation in insert behavior can affect component consistency, machine uptime, and production planning.
Before introducing the UHD solution, the application used imported CBN inserts. Although the existing process could perform the operation, sustained production revealed several limitations:
| Item | Application Detail |
|---|---|
| Industry | Automotive components |
| Workpiece | Automotive transmission coupling gear |
| Material and hardness | 16MnCr5 carburized hardened steel, HRC 58–62 |
| Machining area | Inner bore and end face |
| Machining mode | Continuous cutting, finishing, dry machining |
| Insert solution | UHD UPN605 C06, VBGW160404 Composite Brazed CBN Insert |
| Cutting speed, Vc | 160 m/min |
| Depth of cut, ap | 0.1 mm |
| Feed, f | 0.01 mm/rev |
The UHD solution combined insert design, manufacturing consistency, and machining parameter optimization. The objective was not simply to increase cutting speed, but to establish a more stable finishing process for hardened steel gear production.
The insert combines a carbide substrate with a brazed CBN composite layer. This structure is designed to provide overall strength together with the wear resistance and thermal stability required for continuous finishing of hardened steel.
The cutting geometry was optimized for approximately 0.1 mm finishing allowance. A steadier cutting action helps reduce the risk of visible tool marks and supports a more consistent finished surface.
Precision brazing control supports consistency in CBN tip position and angle. This reduces variation between inserts and contributes to more predictable dimensional performance across production batches.
The process was adjusted to operate at 160 m/min while retaining dry‑cutting stability. Tool selection and cutting conditions were evaluated together rather than as separate variables.
Compared with the previously used imported CBN inserts in the same application, the UHD Composite Brazed CBN Insert delivered the following reported process improvements:
| Performance Indicator | Previous Insert | UHD UPN605 C06 | Observed Change |
|---|---|---|---|
| Cutting speed | 140 m/min | 160 m/min | Increased by 20 m/min |
| Cycle time per part | 4 seconds | 3 seconds | Approximately 25% shorter |
| Tool life per cutting edge | 50 parts/edge | 250 parts/edge | 5× longer tool life |
During continuous production, surface tool marks were visibly reduced, dimensional variation became more controlled, and fewer insert changes were required. These factors supported a more stable automated machining rhythm.
For high‑volume gear finishing, tool performance should be assessed beyond a single cutting edge. Repeatable insert geometry, stable wear behavior, and reliable process matching can all influence line‑level performance.
This composite brazed CBN insert approach is relevant where continuous finishing is required on carburized and hardened steel components with small machining allowances. Similar evaluation logic can be applied to automotive gears, bearing components, wind power transmission parts, and other hardened steel workpieces. Actual insert grade, geometry, and cutting parameters should be selected according to material condition, machine rigidity, allowance, tolerance, and production requirements.
UHD supports B2B manufacturers with CBN and PCD cutting tools, composite brazed CBN insert, formed tools, and non‑standard tooling solutions. With in‑house CBN and diamond material development, digital manufacturing, precision optical inspection, and application‑oriented technical support, UHD works with customers to match tool design and cutting conditions to demanding metal‑cutting operations.
Share your workpiece material, hardness, machining area, allowance, cutting parameters, and current tool information. UHD can evaluate your application and recommend a suitable CBN insert solution.
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