What a golden sample is
A golden sample is a physical unit, or a set of parts, that the buyer and the manufacturer formally approve as the standard for production. It is signed, dated, labeled with its revision and kept by both sides. During production, inspectors compare units against it, particularly for appearance, feel and fit, where written requirements are hard to make precise.
A golden sample does not replace the specification; it complements it. Dimensions, electrical limits and test criteria belong in drawings and test plans. The golden sample shows what acceptable looks like for the rest: color, gloss, texture, button feel, gap consistency and packaging presentation.
Two meanings of “golden”
Factories also use the term for a golden unit in testing: a known-good board or product used to check a test fixture before a shift starts. If the fixture fails the golden unit, the fixture is wrong, not the product. The two uses are related but should not be confused in an agreement. This page covers the approval sample; test fixtures are covered under ICT and FCT.
When to create one
A golden sample should come from the production process, not an engineering bench. In practice that means:
- Parts from approved production tooling, after mold trials are closed
- Assembly on the production line, by line operators, with production fixtures
- The released BOM and firmware revision
For most products that happens during PVT or the pilot run, once the design is frozen. A sample that was hand-built, reworked or picked as the best of a batch shows what the factory can do once, not what it will do every day.
Limit samples
One perfect unit cannot show how much variation is acceptable. Limit samples, also called boundary samples, fill that gap. Each shows the worst acceptable condition for one attribute: the lightest and darkest acceptable color, the largest acceptable sink mark on a given surface, the widest acceptable gap. Pair them with surface classes, which grade each surface by how visible it is in normal use (often labeled A, B and C), so inspectors know where each limit applies.
What to record with a golden sample
| Record | Purpose |
|---|---|
| Product name, BOM revision, firmware version | Ties the sample to a specific configuration |
| Date, location and signatures from both sides | Shows the sample was approved, and by whom |
| Tamper-evident seal or label | Prevents quiet substitution |
| Photos from standard angles | Allows comparison if the sample is damaged or lost |
| Measurement and test data | Records the sample’s actual values, not just “passed” |
| Accepted deviations | Lists anything approved that differs from the drawing |
Keep at least two identical sets: one with the factory’s quality department and one with you. If a third-party inspector checks shipments against AQL criteria, they need access to a set as well.
Keeping golden samples current
Golden samples age. Plastics can yellow, colors shift under light, batteries self-discharge and finishes wear from handling. Store them away from sunlight and replace them on a schedule.
Any engineering change that affects appearance or function should trigger a new golden sample and the withdrawal of the old one. An outdated sample left on the inspection bench becomes a source of disputes.
Common mistakes
- Approving a hand-built or reworked unit as the golden sample.
- Keeping only one copy, at the factory.
- Recording no revision or firmware version.
- Using a golden sample for requirements that need a measured limit.
- Not replacing it after a design or material change.
Where Zefinity helps
A reference sample settles appearance questions only if both sides trust where it came from. Within production readiness and QA follow-up, Zefinity helps make sure reference samples come from the production line, are recorded properly and are replaced when the product changes, so inspection on the factory floor and acceptance on your side use the same standard.
Frequently asked questions
Who should sign the golden sample?
Someone with authority on each side, typically the buyer's product or quality lead and the factory's quality manager. If a third-party inspector will check shipments, give them a copy and the approval record. The signature matters less than the record of what was approved, which configuration it represents and where each copy is kept.
Is a golden sample contractually binding?
Only as far as your agreement says it is. Reference the golden sample, its revision and its approval record in the quality agreement or purchase terms, and state that production must match it within the agreed limits. Without that link, it is a useful reference but a weak basis for rejecting goods.