An eyewear factory audit is not a tour. It is a walk down the production line asking, at each stop, what is being checked and what the record says. A frame passes through roughly eight workstations between raw sheet and packed carton, and a weakness at any one of them shows up later as returns. This article is a route you can print and carry, with the records to request and the red flags to watch for at each stop.

Before you go: documents to request in advance

The audit starts before arrival. Ask for the documents that should already exist, so you can check them against what you see on the floor:

·      Company registration and factory license.

·      Quality manual or process flow chart for the product lines you will buy.

·      Recent third-party test reports (EN ISO 12870, nickel release, REACH, CPSIA where relevant).

·      List of key machines with their maintenance logs.

·      Organisation chart for production and QC staffing.

If these are not available before the visit, treat that as the first finding. A factory that cannot produce its own paperwork is unlikely to be recording quality at the workstation level.

Station 1-3: incoming material, cutting, CNC

Station 1 — Incoming material inspection

Raw acetate sheet, metal wire and plating batches are received here. Ask to see the incoming inspection log: what is measured, what is rejected, and how non-conforming material is quarantined. A pile of unlabelled sheet with no incoming record is a sign that material traceability — and therefore colour consistency — is not controlled.

Station 2 — Cutting / blanking

Acetate blocks are cut to profile; metal is stamped or laser-cut. Look for nesting discipline (scrap control) and edge quality. Ask for the cutting tolerance standard and whether off-cut material is segregated by colour way, because mixing scrap between colour ways is a classic source of streaks.

Station 3 — CNC / milling

The front is milled to shape and the lens groove cut. This is where dimensional accuracy is set. Ask for the gauge used to verify lens aperture and bridge, and how often it is calibrated. No calibration sticker on the gauge is a finding in itself.

Station 4-6: tumbling, assembly, hinge riveting

Station 4 — Tumbling and polishing

Acetate parts are tumbled for a defined number of hours. Ask for the tumbling time standard per model and how it is enforced — a timer on the barrel, not a worker's judgement. Under-tumbled parts that move downstream become the "looks unfinished" returns.

Station 5 — Assembly

Temples, hinges and pad arms are fitted. Check that hinge fit is consistent and that pad arm alignment is jig-checked rather than eye-checked. Ask how many assemblies are rejected at this station and where they go.

Station 6 — Hinge riveting / soldering

For metal frames the hinge is riveted or soldered; for acetate the hinge is typically inserted and riveted. This is a fatigue-critical joint. Ask for the riveting pressure standard and the hinge-pull check, if any. A hinge that releases under pull is the most common mechanical failure in the field.

Station 7-8: straightening, final QC and packing

Station 7 — Straightening and adjustment

Finished frames are checked for alignment — temple symmetry, face form, pupillary fit. Ask whether adjustment is done to a measured standard (a face-form gauge) or by hand feel. Hand-feel-only adjustment produces inconsistent fit across a batch.

Station 8 — Final QC and packing

The frame is inspected against the AQL plan, then packed with case, pouch and cloth. Ask for the AQL level applied and the most recent inspection report with accept/reject numbers. Packing should match the labelling and tracking requirements for the destination market — a mismatch here is a customs or retail problem later.

Records to ask for at each station

Red flags that should stop you from placing the order

·      No incoming inspection at all— material is used as received, so colour and plating consistency are uncontrolled.

·      Records that cannot be produced on the floor— the QC story exists in a binder for visitors but not at the station.

·      One person doing both production and QC on the same bench— no independence between making and checking.

·      Calibration stickers missing or expiredon the gauges that set dimensions.

·      Mixed colour-way scrapvisible at the cutting station.

·      No AQL plan— "we check all" is not a plan; it is usually a sign that sampling is informal.

·      Test reports that predate the current model rangeor name different models than you are buying.

Frequently asked questions

Do I need to visit in person?

Not always. A recognised third-party audit (such as a social- and quality-compliance inspection) can stand in, and a live video walk can cover the route above. In person remains best for reading the floor.

How long does a line audit take?

A focused eyewear line audit is a full day: document review in the morning, station walk in the afternoon, and report writing after. Rushing it to two hours misses the records.

What AQL should I expect?

Many eyewear buyers use AQL 2.5 for major defects on the final inspection. The point is not the exact number but that a plan exists and is applied consistently.

Is a clean workshop the same as a capable one?

No. Tidiness helps but the proof is in the station records and the gauge calibration. A spotless floor with no incoming log is still a risk.

Should I audit before the first order or after?

Before. An audit after a problem is already a damage-limitation exercise; an audit before tells you whether to place the order at all.