How Acne Patches Are Inspected: AQL, Defect Classes and Batch Records
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- Issue Time
- Nov 10,2026
Summary
Nobody inspects 10,000 patches one by one. Inspection is a sampling decision, and the AQL table is where a buyer's quality expectation either becomes enforceable or stays a feeling. How to read AQL tables, classify patch defects, and what a batch record must contain.
Nobody inspects ten thousand patches one by one. Inspection is a sampling decision, and the sampling table is where a buyer's quality expectation either becomes enforceable or stays a feeling. Two suppliers can both say "we check every batch" and mean completely different things — one is running a defined AQL with a signed record, the other is opening a box and looking at it.
This page is about the difference, because it is the difference that decides whether a claim on defective goods can be settled with a document or an argument.
The three inspections that matter
An order passes through three gates, and a buyer usually only hears about the third.
Incoming material. The hydrocolloid sheet, release liner, pouch film and inks are checked against their own certificates before release to the line. If the sheet lot is wrong, everything downstream is wrong and nobody notices until the patch lifts.
In-process. Coating thickness, die-cut registration, seal temperature and print registration are checked at fixed intervals, not at the end. This is the gate that catches drift while it is still cheap to correct.
Pre-shipment. The finished cartons are sampled against the AQL you agreed. This is the one a buyer's own inspector attends, and the only one that produces a document you can hold against a supplier.
How to read the AQL table
The table is smaller than it looks. Lot size gives you a sample size; the AQL you agreed gives you an acceptance number and a rejection number. The two numbers are always one apart, which is why the procedure has no middle outcome.
A 10,000-unit lot is inspected on 200 patches. That number surprises buyers who assume "sampled" means "a few dozen". It also explains why the inspection cost is not proportional to the order: doubling the lot barely moves the sample size, because the sample is sized to the confidence you want, not to the quantity you bought.
Three practical notes. Critical defects usually run at AQL 1.0 or tighter, or at zero acceptance — a lot with one unsealed pouch is a different conversation from a lot with one crooked label. Cosmetic appearance commonly sits at 2.5. And the standard's name matters: ISO 2859-1 and GB/T 2828.1 describe the same procedure, so a Chinese supplier and a European buyer are usually arguing about the same table without knowing it.
Common misreading: AQL 2.5 does not mean "2.5 % of the delivery may be defective". It is a quality level tied to a sampling plan and a long-run process average, not a per-lot allowance. A lot can pass and still contain defectives — that is what the consumer's risk in the plan means.
Classifying patch defects
Generic defect lists do not transfer. A patch has its own failure modes, and they do not split the way a garment's do.
The line between major and minor is where quotations and complaints usually diverge, so it belongs in the purchase order with a photograph attached. "Edge quality to approved sample" is a sentence; a signed photo of an acceptable edge and a rejected edge is a specification.
What a batch record should contain
Ask for one page. A supplier who can produce it in an hour runs a quality system; one who needs a week is reconstructing it.
- Material lot numbers for the hydrocolloid sheet, release liner, pouch film and each ink
- Coating parameters: thickness, line speed, oven temperatures at the recorded setpoints
- Die number, cut registration check and the sheet layout used
- Room temperature, relative humidity and the cleanroom class at the time of production
- First-article approval and the interval in-process checks, with the results written down
- Print first-off signed against the approved proof, plus the colour measurement recorded
- Seal parameters and the seal-strength or leak test result for the run
- Final inspection record: AQL used, sample size, defects found, accept or reject, and the retention sample number
Retention samples and the stability file
Every batch should leave a retention sample behind, stored under the same conditions the label claims. That sample is what settles a complaint eighteen months later, when nobody can reproduce the run. It is also what an auditor asks for first.
Retention alone does not prove shelf life; the stability file does, and the two are related — retention shows what was made, stability shows what happens next. For how the declaration is established and which pack formats shorten it, see what shelf life a hydrocolloid patch carries.
What to look at on inspection day
An inspector with a clipboard can miss the things that matter most, because the defects that cost money are structural rather than visual.
from different pallet positions
Not the top layer. Print the carton numbers into the report, so a later dispute has a location rather than a memory.
in the sample
A leaking seal shows as air moving, not as a visible hole. This is the single most valuable thirty seconds of a pre-shipment inspection on this product.
onto clean skin or glass
Feel for tack and for adhesive transfer. A patch that leaves a ring on glass will leave a ring on a face.
at arm's length
Batch number, manufacture date and expiry must be legible after the pouch has been handled. If they smudge, the coding method is wrong, not the operator.
by weight
Weigh one pack and divide by the unit weight. It catches a short count faster than opening twenty pouches, and it is non-destructive.
The checklist to send before the run starts
Why this is worth the paperwork
Quality conversations fail for a boring reason: the two sides never agreed what "good" means, so every batch is negotiated again from scratch. An AQL, a defect photo set and a batch record turn that negotiation into a comparison against a number.
It also changes what a supplier can promise you. A factory that runs to a defined AQL can quote a defect rate and stand behind it; one that inspects by eye can only quote optimism. If you are still comparing suppliers, the 12-point sourcing checklist covers where inspection sits among the other eleven.
Send the AQL you work to and the defect classes that matter to your channel, and we will return the batch record format we use, the retention policy, and a sample inspection report from a recent run.
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