Quality control inspection: factory audits, the three inspections and AQL

Once goods are on a ship and the balance is paid, your leverage is mostly gone. Defects found at your warehouse cost you freight both ways, a delayed launch and a negotiation from a distance. Defects found at the factory can be sorted, reworked or replaced before anything leaves.

An inspection is only as good as the standard it checks against. "Check the quality" gives an inspector nothing to measure. A spec with measurements and tolerances, a sealed approved sample and a purchase order that states the inspection standard give them a pass or fail line. As the course puts it: they said it on WeChat is not a quality system.

Our tech pack guide covers the written spec.

A factory audit looks at the supplier, not your goods. It answers "can this factory make my product reliably, and how does it run?" before you commit. The common types:

Social audits usually follow a named methodology. Sedex's SMETA, for example, assesses a site against local law and the ETI Base Code, which is founded on ILO conventions. If a retailer asks for an audit, ask which methodology it accepts before you book one.

For a small first order, a video walk-through and a check of who you're really dealing with (factory or trading company) is often enough. Our guide to finding a manufacturer covers how to verify a supplier from public records.

Inspection firms set the pre-shipment timing in their own terms. SGS describes its final random inspection as happening once the batch is fully made and at least 80% of the products are packed; QIMA inspects when production is at least 80% complete. SGS also offers loading supervision, where the inspector watches the cartons go into the container and seals it.

You don't need all three on every order. A rough rule: book a pre-shipment inspection on any meaningful international order; add a pre-production check when a material is custom or hard to replace (a dyed fabric, a molded part); add a during-production check on a large or first run, where a repeated defect would be expensive.

AQL stands for acceptance quality limit (you will also see "acceptable quality level"). It is the worst defect rate you are willing to accept on average, set per defect class. An AQL sampling plan turns that into two numbers for a given lot: how many units to pull at random, and how many defects in that sample are allowed before the lot fails.

The plans come from two standards:

• ISO 2859-1, Sampling procedures for inspection by attributes, Part 1: sampling schemes indexed by AQL for lot-by-lot inspection. The third edition, ISO 2859-1:2026, was published in January 2026 and replaced the 1999 edition and its amendments. It adds skip-lot procedures.
• ANSI/ASQ Z1.4, Sampling Procedures and Tables for Inspection by Attributes, the American national standard. ASQ describes it as a direct descendant of the US military's MIL-STD-105E, which the Department of Defense stopped supporting in 1995, recommending Z1.4 as its replacement.

Both are sold by their publishers; inspection firms use them and will tell you which one, and which edition, their report follows. How a plan works, in outline:

1. 01Lot size and inspection level give a sample size. A bigger lot means a bigger sample, but not in proportion. The inspection level sets how hard to look; ask which level the inspector proposes.
2. 02The AQL per defect class gives the accept and reject numbers for that sample size.
3. 03Defects are sorted into classes: critical (unsafe or non-compliant), major (a functional defect or a large visible flaw) and minor (cosmetic, doesn't affect function). QIMA, for one, treats a critical defect as an immediate fail.
4. 04The inspector counts defects per class. If any class goes over its accept number, the lot fails that class.

The golden sample (also called the approval or sealed sample) is the unit you approved for production, signed or sealed so nobody can swap it. It is what the inspector compares color, hand, measurements, labels and finish against.

• Keep one with the factory and one with you, both sealed and labeled with the date and the revision.
• Give the inspector photos and measurements of it along with your spec, so they can check without calling you.
• Keep it out of circulation, so the reference stays untouched.

Measurements need tolerances to be checkable. "Chest about 54 cm" can't fail; "chest 54 cm, plus or minus 1 cm" can.

QIMA, V-Trust and SGS are examples of firms that offer third-party inspections; naming them is not a recommendation, and smaller local firms and independent inspectors do the same work. Get a quote from more than one, and check they cover your product type in your factory's city.

What to have ready when you book:

• The factory's name, address and contact, and the expected inspection date
• Your purchase order: quantities by style, color and size
• The spec or tech pack with tolerances, and photos of the golden sample
• The AQL per defect class, and any tests you want (a wash test, a seam pull, a zipper cycle, a drop test for fragile goods)
• The packaging, labeling and carton marking requirements
• The known weak points: the defect you already saw in sampling

Tell the factory the inspection is a condition of the balance payment, and confirm the date with them so the goods are actually ready. Ask the inspection firm what it charges if the inspector arrives and the goods aren't.

Check that a pre-shipment report has:

• An overall result (pass, fail or pending your decision) and the standard and AQL used
• Quantity: units finished and packed against the order, and cartons counted
• Packaging: inner packs, carton marks, carton dimensions and weights
• Conformity: color, materials, construction, dimensions, artwork and labels against the golden sample and spec
• Measurements: the units measured and any out of tolerance
• Function and on-site tests, with results
• Defects found, by class (critical, major, minor), against the allowed numbers
• Photos of every defect and of the cartons, with the inspector's notes

QIMA, for one, issues its report the same day as the inspection, with a pass or fail result, a findings summary and photos. Read it before you release the balance, and ask questions while the inspector's notes are fresh.

A fail is a decision point, not an emergency, if you agreed the remedies on the purchase order before production. The usual options:

The Product Sourcing Secrets course covers how to write those remedies into the order before production, including who pays for a re-inspection after rework.

Two rules hold in every case: don't pay the balance until the goods pass or you have agreed the remedy in writing, and keep the report. It is your evidence if the problem shows up again on the next order.