Case Study: Coil Spring Supply for an online marketplace seller in North America
Source:Case /
Time:2026-09-18
Coil Spring for An online marketplace seller in North America
An online marketplace seller came to us with a coil spring programme for North America. The brief was ordinary and unforgiving at the same time: a fixed launch window, a landed cost that had to survive freight and duty, and a part that had to match an existing sample. This case records what was specified, what went wrong in sampling and how the bulk order landed.
The starting point
- Lead time that slipped twice before bulk started
- A supplier who changed material without saying so
- Warranty claims traced back to a single lot

What was specified
| Part | Coil Spring |
|---|---|
| Client | An online marketplace seller |
| Market | North America |
| Volume | 5,000 pieces across 2 specifications |
| Base material | Tempered Glass |
| Sampling rounds | 3 |
| Delivery window | 6 weeks from PO to ex-factory |
| Compliance | RoHS |
How it was resolved
- The specification was rebuilt around Tempered Glass and the tolerance locked before bulk.
- A pre-production sample was approved and kept as the golden reference.
- Production ran with in-line inspection and a mid-run photo report.
- Cartons were packed to the client's own barcode and ratio specification.
- Documentation shipped with the goods instead of after them.

Result
- 5,000 pieces delivered inside the 6-week window.
- Unit cost held within 2.0% of the original quotation.
- Inspection-related rejection stayed under 0.5%.
- The specification is on file, so reorders reproduce the approved sample.
What we would repeat
Lock the material standard before sampling. Once the base changes, every downstream approval has to be redone and the calendar slips.
Planning something similar?
Ask for the current catalogue and the specification sheet for this line.



