{"id":711,"date":"2026-10-14T09:00:00","date_gmt":"2026-10-14T09:00:00","guid":{"rendered":"https:\/\/odmhome.com\/blog\/?p=711"},"modified":"2026-10-14T17:04:29","modified_gmt":"2026-10-14T09:04:29","slug":"aql-sampling-inspection-guide","status":"publish","type":"post","link":"https:\/\/odmhome.com\/blog\/aql-sampling-inspection-guide\/","title":{"rendered":"AQL Sampling Without the Jargon: How to Inspect a Production Run"},"content":{"rendered":"

AQL \u2014 acceptable quality limit \u2014 is the most quoted and least understood term in sourcing. It is not a promise of quality; it is a sampling plan, and its whole purpose is to answer a narrow question: given a batch of a certain size, how many units should be randomly checked, and how many defects can be found before the batch is rejected. In short, AQL Sampling Without Jargon is the deciding factor for most buyers.<\/p>\n

Used properly it is a useful, cheap tool. Used as a substitute for thinking about quality, it lets a bad batch through with paperwork in order.<\/p>\n

What the three numbers mean<\/h2>\n\n\n\n\n\n\n\n
Level<\/th>\nUsed for<\/th>\nPractical meaning<\/th>\n<\/tr>\n<\/thead>\n
General II<\/td>\nDefault for most consumer goods<\/td>\nThe standard sample size for a given batch<\/td>\n<\/tr>\n
General I<\/td>\nLighter checking<\/td>\nSmaller sample; more risk passing through<\/td>\n<\/tr>\n
General III<\/td>\nTighter checking<\/td>\nLarger sample; used after a failure or for high-value goods<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Then come the defect tolerances, usually quoted as three numbers: critical, major, minor. Critical is zero \u2014 always. A safety defect, a wrong plug standard, a sharp edge, a battery that is not secured: one is one too many, and no sampling plan permits one. Major defects are functional or cosmetic problems a customer would return the product for. Minor defects are finish issues most customers would not act on.<\/p>\n

The common arrangement for consumer electronics is zero critical, 2.5 major and 4.0 minor, but the numbers matter less than two things: agreeing them before production, and defining in writing what counts as major for your<\/em> product.<\/p>\n

Define the defect list, not just the level<\/h2>\n

This is where brands get value from an inspection. A generic checklist covers packaging, quantity, colour and obvious damage. A useful one is specific to your product: for a smart plug, that means the socket grips a plug firmly and does not rattle, the button cycles the relay audibly, and the Wi-Fi indicator reaches pairing mode within a stated time. For a camera, it means the IR cut filter actually switches and the night image is in focus. Write those tests down, with pass criteria, and give them to the inspector.<\/p>\n

Also specify the sample handling: units are picked at random from finished, packed cartons, from across the production run rather than from the first pallet. A sample drawn from the top of one carton tells you about one carton.<\/p>\n

Inspection is not quality control<\/h2>\n

An inspection happens at the end and can only reject what has already been made. The controls that prevent defects are earlier: incoming component checks, in-process checks, and end-of-line functional testing on every unit. The framework is described in the IQC\/IPQC\/OQC quality system<\/a>, and the practical distinction is simple \u2014 OQC sampling detects, in-process control prevents. Ask what percentage of units get functional testing at end of line, because for a connected device, 100% functional test is the norm and anything less is a cost decision you should know about.<\/p>\n

What to do with a failed inspection<\/h2>\n

Agree the outcome in advance. The usual options are: rework and re-inspect at the factory’s cost, accept with a price concession, or reject and remake. The third is rare and expensive, and the first is where most cases land. What matters is that the decision rule exists before the failure, because a negotiation held while a container is waiting is a negotiation you lose.<\/p>\n

Then close the loop: a defect that appears at 2% is information about a process step, and the corrective action belongs in production, not in the inspection report. A second batch with the same defect distribution means the corrective action was cosmetic.<\/p>\n

Practicalities worth arranging<\/h2>\n