What should inspection check?

Inspection fails when it is unspecified. Two people can both "check quality" and check different things, which is why the checklist matters more than the inspector.

The four stages

1. Incoming material. Mill certificate for the steel, wire diameter, sheet thickness. Catch grade substitution here, where it is cheap to fix.
2. In-process. After casting or stamping, after polishing, after coating. Coating defects are far cheaper to catch before assembly.
3. Finished goods. The real inspection, against the approved sample.
4. Packing. Correct quantity per box, correct card, correct insert, no mixed styles.

The finished-goods list

• Dimensions against the drawing, with tolerance.
• Weight in grams versus target — the fastest proxy for thickness drift.
• Finish evenness — no polishing swirls, no hazy edges, no missed recesses.
• Colour against the master sample under controlled light.
• Logo placement, size, legibility, and whether the mark is complete.
• Closure function — open and close every unit in the sample, not one per carton.
• Surface — pits, scratches, tool marks, coating inclusions.
• Joints — soldered jump rings and hinges, tested by hand.

Defect classes

Critical defects are not sampled; they are 100% checked, because one cut finger costs more than the inspection.

What buyers should ask for

Photos of the inspection record, the sample size used, and the number of defects found by class. A supplier who reports "all good" without a count has not inspected; they have looked.

The most useful habit is the golden sample: a signed, dated reference piece held by both sides. Every inspection compares against it. Without one, "the colour is different" has no arbiter.