How a German reducer OEM got DIN 6 spur gears in 45 days: module 3, 23 teeth, 20° pressure angle, 20CrMnTi, Ra≤0.8μm, 200 pieces.
A German reducer manufacturer placed a custom spur gear order with Geyon: module 3, 23 teeth, 20° pressure angle, 40mm face width, φ25H7 bore, DIN 3962 quality 6, surface roughness Ra≤0.8μm, 20CrMnTi carburized and quenched. First batch 200 pieces, 45-day lead time. Measured results: cumulative pitch deviation ≤0.012mm, lead deviation ≤0.009mm, first article passed complete inspection, batch supply confirmed. Here is how the job was run.
The customer is a German gearbox/reducer OEM sourcing a precision gear for the reducer main shaft. Drawing requirements: module m=3, teeth Z=23, pressure angle α=20°, face width b=40mm, outside diameter φ78mm, bore φ25H7. Quality class DIN 6 per DIN 3962, surface roughness Ra≤0.8μm. Material 20CrMnTi, carburized and quenched, effective case depth 0.8–1.2mm, surface hardness 58–62 HRC, core hardness 30–42 HRC. First batch 200 pieces, lead time 45 days from order to shipment.
A DIN 6 tooth flank has to be ground. After hobbing we leave 0.2–0.3mm grinding allowance — too little and heat treatment distortion leaves nothing to correct; too much and grinding time doubles.
Case depth and hardness consistency mattered just as much. The customer checks surface roughness closely, and batch-to-batch drift is a rejection risk.
Every piece shipped with a full dimensional report — profile, lead, pitch — formatted to the customer’s template.
And the 45-day clock started at order, with heat treatment and grinding taking most of it. Scheduling had no slack.
The route: blanking → turning → hobbing → carburizing & quenching → gear grinding → deburring → inspection → packing. Six practical steps.
Blank and turn. Cut the blank, rough turn, semi-finish the φ25H7 bore with allowance for final turning.
Hob the teeth. Leave 0.2–0.3mm grinding allowance. That number was not guessed — we cut trial pieces first, measured the heat treatment distortion, then locked the allowance.
Carburize and quench. 20CrMnTi, furnace temperature and soak time controlled so the case stays at 0.8–1.2mm and the flank at 58–62 HRC. Parameters were set from the trial-piece hardness gradient data, not from habit.
Grind. Generating grinding on a worm-wheel grinder to DIN 6, flank Ra≤0.8μm. See our gear grinding process for the machine setup.
Inspect — the step the customer watched closest. Gear measuring center reports profile, lead and pitch; CMM rechecks the bore and dimensional tolerances; hardness spot checks on the flank. Reports follow the customer’s template and ship with the goods. Sample a gear inspection report to see the format.
Pack. Rust-preventive paper, vacuum bag, wooden case, built for long sea freight.
| Item | Result |
|---|---|
| Quality class | DIN 6 (DIN 3962), flank Ra≤0.8μm |
| Cumulative pitch deviation | ≤0.012mm |
| Lead deviation | ≤0.009mm |
| Flank hardness | 58–62 HRC, case 0.8–1.2mm |
| Lead time | 45 days, order to shipment |
| First batch | 200 pieces, first article passed, all sampling passed |
| Follow-up | Batch supply confirmed by customer |
Grinding allowance was set from trial cuts, so distortion was known before production and grinding ran without rework.
Heat treatment stayed stable. Case depth drift shows up directly on the ground flank hardness, so the furnace curve was fixed from measured data.
The report package was complete — profile, lead, pitch, every item listed. The customer’s first article inspection passed in one round.
Packing followed their habit: rust-proof, vacuum, wood case. No issues in transit.
If you are a gearbox maker, robot joint producer, or high-end equipment OEM with a precision gear drawing, send us the module, tooth count, quality class and material. We will come back with a process plan and a quote. Contact Geyon — customization flow, grinding process, inspection reports, whatever you want to talk through.
Upload a 2D/3D drawing (STEP, DXF, PDF) — we reply with a quote and lead time.