Precision NTC Ring Terminal
Precision NTC Ring Terminal
SUS304 ring terminal for a European NTC temperature-sensor programme — anonymised PPAP summary.
| Material | SUS304 (304 stainless), 0.25 mm |
|---|---|
| Part form | Ring terminal, Ø3.2 mm mounting hole, ~21 mm overall |
| Controlled dimensions | 5 (overall length, width, ring OD, inner diameter, hole) |
| Tolerance classes | ±0.3 mm on length/width; +0/−0.05 mm on ring OD; +0.10/−0 on ID; +0.20/−0 on hole |
| Process route | 8 steps, including 4 h vibratory polishing |
| Inspection | 100% appearance; GB/T 2828.1 AQL 0.25 sampling on dimensions |
| First-article result | 25/25 dimensional readings within tolerance (accepted) |
| Packing | 5,000 pcs per bag (anti-collision) |
| Documentation | QA report + material identification + delivery note |
The challenge
A 0.25 mm stainless ring terminal is thin enough that burrs and deformation are the whole game. The part must be flat and burr-free inside and outside, the mounting hole has to stay on position, and the ring OD must hold a +0/−0.05 mm tolerance so it seats correctly on the sensor assembly. At that gauge, a burr that looks cosmetic becomes a fit and contact problem downstream.
How AUNOV runs it
- Incoming material check — SUS304 sheet verified before release to production
- Blanking, then stamping the ring shape
- Punching the mounting hole and cutting the edge to final size
- Four-hour vibratory grinding and polishing to remove burrs and smooth both faces
- 100% appearance inspection, plus dimensional sampling to GB/T 2828.1 AQL 0.25
- Packing 5,000 pcs per bag, with QA report, material ID and delivery note
The quality evidence
On the PPAP first article, five controlled features were measured on five parts — 25 readings in total — and every reading fell inside its tolerance band, so the report was accepted (AC). Dimension sampling during production follows GB/T 2828.1 (G-II) at AQL 0.25 for size and AQL 0.40 for appearance, with a 100% appearance check before packing. Capability indices (Cpk) are reported per programme on the characteristics a customer nominates as controlled.
Frequently asked questions
Can AUNOV produce thin stainless ring terminals without burrs?
Direct answer: Yes. This 0.25 mm SUS304 ring terminal goes through a four-hour vibratory grinding and polishing step after punching, then a 100% appearance inspection, so burrs inside and outside the ring are removed before packing.
How are ring terminal dimensions inspected?
Direct answer: Five controlled dimensions — overall length, width, ring OD, inner diameter and hole — are checked with calipers. The PPAP first article measured five parts (25 readings) and all were within tolerance; production sampling follows GB/T 2828.1 at AQL 0.25.
What documentation comes with a ring terminal shipment?
Direct answer: Each shipment carries a QA report, material identification traceable to EN 10204, and a delivery note. Material certificates and PPAP-level documentation are available for automotive and sensor programmes on request.
Have a similar stamped or drawn part?
Send the drawing and material — AUNOV returns a DFM review and a quote within 24 hours.
Request a quoteSources Behind These Examples
Each example is built on measured material data and the process taxonomy set out by these standards. We keep the lot data behind each part on file for first-article review.
- ASTM E646 — Standard Test Method for Tensile Strain-Hardening Exponents (n) of Metallic Sheet Materials. The n-value sets how much a wall can thin before necking.
- DIN 8584 — Manufacturing processes, forming: classification of deep drawing operations and their subgroups.
- ISO 20482 — Metallic materials: Erichsen cupping test, a formability measure complementary to LDR.
- Wikipedia: Anisotropy — explains the r-value and why earing directions form.
- Wikipedia: Work hardening — why redraws and intermediate annealing matter.