01How the process works
A hob or shaper cutter generates the involute tooth form on a blank; after heat treatment, precision gears are ground to correct distortion. Bevel gears use dedicated generators. Gear accuracy is graded by profile, helix and pitch deviations measured on gear measuring machines.
Case depth and surface hardness after carburising or nitriding are as important as geometry. Our checks combine gear measurement reports, heat treatment records, hardness traverses and, for gearboxes, run-in and noise tests.
- Blank. Forged or bar blank machined.
- Cutting. Hobbing, shaping or broaching.
- Heat treatment. Carburise, quench, temper or nitride.
- Finishing. Grinding or honing.
- Inspection. Gear measurement, hardness, case depth.
02What typically goes wrong
| Defect | Typical cause | How it is found |
|---|---|---|
| Profile and helix deviation | Tool wear, set-up, distortion | Gear measuring machine |
| Pitch errors | Machine indexing | Gear measuring machine |
| Low case depth | Carburising cycle | Hardness traverse |
| Grinding burn | Grinding parameters | Nital etch |
| Heat treatment distortion | Quench, fixturing | Runout, gear measurement |
| Noise | Accumulated errors | Run-in or noise test |
03Where an inspector should look
01
Before production
- Gear data and accuracy grade
- Heat treatment specification
- Measurement method
02
During production
- First gear measurement
- Furnace charts
- Sample hardness traverse
03
After production
- Gear inspection reports
- Burn check
- Assembly and contact pattern
04Standards and references
ISO 1328 (gear accuracy), ISO 6336 (gear rating), ISO 18203 (case depth), AGMA 2015.
Standards are named for orientation. The applicable edition and acceptance criteria are those in your contract and specification.
05How we support buyers of gear cutting parts
Dimensional and Geometrical InspectionDimensional, GD&T and drawing compliance verification, CMM witnessing, laser measurement coordination and first article layouts.
Manufacturing and Special Process AuditsProcess audits of casting, machining, welding, heat treatment, plating and moulding, with VDA 6.3 style evaluation.
Mechanical Equipment InspectionInspection of rotating and static mechanical equipment: assembly, hardness, mechanical, load, pressure, leak and running tests.