Rough turning the large end face of a carburized and quenched 20CrMnTi driven gear at HRC 60–64 requires more than a wear-resistant cutting edge. Where the tool repeatedly enters and leaves the material, impact loading can cause edge chipping before gradual wear becomes the main tool-life limit. Uneven machining allowance adds another source of load variation.
UHD evaluates integral brazed CBN inserts as a candidate for this interrupted roughing operation. The objective is to remove stock reliably and leave a consistent allowance for finishing—not to use one insert configuration for every gear-machining operation.
On an interrupted gear face, the edge experiences repeated changes in cutting load. If the allowance also varies around the workpiece, the most demanding engagement may be substantially different from the nominal cutting condition. A configuration that performs acceptably through a lighter section may still fail at a heavier entry.
Changing the insert without addressing unstable clamping or excessive allowance variation may leave the underlying failure mechanism unresolved.
Within UHD’s gear-machining approach, integral brazed CBN inserts are a roughing candidate for large end faces with interrupted engagement and fluctuating stock. Selection focuses on impact resistance and edge integrity rather than wear resistance alone.
The proposed insert must be assessed alongside its edge preparation, seating and support, toolholder arrangement and cutting conditions. The construction name is a starting point for selection, not a performance guarantee.
This configuration addresses stock removal on the gear face. Precision finishing of the bore and locating shoulder, continuous face finishing and tooth-root relief grooving require their own assessments. A successful roughing trial should demonstrate that the remaining stock is sufficiently consistent for the subsequent operation.
| Review area | Information to establish | Why it matters |
|---|---|---|
| Workpiece condition | 20CrMnTi material, heat-treatment condition and HRC 60–64 hardness range. | Defines the material condition being evaluated. |
| Interruption and stock | Entry and exit pattern, nominal allowance and maximum observed stock variation. | Identifies the demanding engagements the trial must represent. |
| Machine and tool support | Machine rigidity, clamping arrangement, toolholder condition and insert support. | Helps distinguish insert limitations from setup instability. |
| Edge and cutting conditions | Edge preparation, cutting speed, feed, depth of cut and coolant practice. | Establishes a documented configuration for meaningful comparison. |
Cutting parameters and edge preparation should be selected for the actual application. Material hardness alone is not enough to specify a production-ready setup.
A longer cutting run is not sufficient evidence of a better process if unexpected chipping still causes stoppages or leaves inconsistent stock for finishing.
No insert construction can establish that outcome on its own. Suitability depends on the interruption severity, stock variation, edge preparation, support and cutting conditions. The proposed configuration requires validation on the customer’s equipment.
Surface condition is relevant, but the main roughing criteria are reliable stock removal, manageable edge damage and consistent allowance for finishing. Final dimensional and surface requirements should also be validated in the finishing operation.
Henan UHD Ultrahard Tools Co., Ltd supplies CBN cutting tools, non-standard tooling and application guidance. For interrupted rough turning of hardened 20CrMnTi gear faces, the review begins with the workpiece and failure conditions—not simply a replacement insert designation.
Share the gear drawing or relevant face geometry, hardness, allowance range, interruption details, machine and fixture information, current cutting parameters and photographs of the damaged edge. These inputs support assessment of an integral brazed CBN candidate, any required tooling adjustments and a controlled trial plan. Production suitability remains application-dependent and must be confirmed through testing.
Tell us your workpiece, quantity, and tooling requirement. Our team will reply with a practical solution.
