How to run a quality inspection using the AQL procedure
Acceptable Quality Limit (AQL) is a standardized quality control procedure used by brands, manufacturers, and 3PLs, to ensure products meet the agreed upon quality standards.
The Acceptable Quality Limit (AQL) procedure is defined in depth by the International Organization for Standardization in ISO 2859-1. This guide provides a quick reference to help you run the AQL process yourself.
The theory behind AQL is that by randomly selecting a statistically significant subset of units within a larger lot, you can quickly determine the quality of the entire lot.
The number of units sampled in the AQL process is dependent on which inspection level is used and the total number of units in the lot. For this guide we use AQL 2.5 Inspection Level S4, because it is the standard level prescribed by Lumi for all parties.
Start by determining how many units will be in your sample batch. The number of sample units depends on the total number of units in the lot. The lot is typically all of the units in a production run.
Once you've determined how many units should be in your sample batch, take note of the maximum number of units with minor, major and critical defects that are acceptable for the lot.
|Total units in lot||Units in sample batch||Maximum units with minor defects||Maximum units with major defects||Maximum units with critical defects|
|3,201 - 10,000||32||2||2||0|
|10,001 - 35,000||50||3||3||0|
|35,001 - 150,000||80||5||5||0|
|150,001 - 500,000||80||5||5||0|
|500,001 - 1,000,000||125||7||7||0|
To get a representative sample, select units randomly from the top, middle and bottom of multiple pallets or bundles.
Avoid picking only from the top of pallets or bundles so that you get a true representation of the entire lot.
Tip: You can use an online number generator to help you randomize which pallets or bundles to pick from.
- Choose your product from the list of Quality Policies to find the right inspection criteria. The inspection criteria gives you a standardized list of defects to look out for, and tells you what tolerances are permitted.
- Examine each of the items in your sample batch. When you see imperfections, make a note of the number of units that are affected and the severity of the imperfection based on the inspection criteria (minor, major, or critical).
- Take photos of the defective units so that they can be reviewed by the Lumi team and the supplier for root cause analysis.
Is your product missing quality policies? We consistently review and update our standardize quality criteria. If you ordered a product and the tolerances are not listed, contact us.
Defects below maximum: If the number of units with minor, major, or critical defects is below the maximum what's acceptable (per the table above) for your lot, it passes inspection.
Defects at or over maximum: If the number of units with defects exceeds the maximum acceptable for your lot (per the table above), report issues as soon as possible. To speed up the process, try to count the total number of defective units. Typically defective units within a production run will be found in close proximity to each other.
Act quickly! Quality issues must be reported within the inspection period to be eligible for remake or refund. If your report is not submitted within the inspection period, it will be assumed that the lot was accepted. If you discover an issue after the inspection period, you can still submit a quality report, so that the issue can be prevented in the future.
Each reported quality issue directly affects a supplier's scoring and keeps our factory network top notch. To report a quality issue, send us an issue report with the following details:
- Order number
- Type of defect (based on the Quality Policies)
- Defect severity (minor, major, critical)
- Total number of units affected
- Photos of the defect
Manufacturers will typically produce up to 10% more units than the ordered quantity — aka "overs". Overs add some buffer room to account for potential quality issues in your order.
If the number of defective units dips below your order quantity by more than 15%, Lumi will take action in the following way:
- For critical defects: Lumi will initiate a remake of the items affected to meet the ordered quantity.
- For minor or major defects: Lumi will review the order, provide a root cause analysis, and a case-by-case correction action plan.
Lumi takes a proactive approach to continuously measuring and improving the quality standards of manufacturing partners in our network. If severe quality issues are reported, or a factory exhibits consistently poor quality, this will be reflected in the manufacturer's scorecard and rankings on the platform.
If you experience recurring quality issues, we suggest moving production to a new supplier by sending a new quote request to the marketplace or sending a supplier a direct request.
Note: You will receive an invoice in the platform to cover overs after they've been delivered. This makes it easier to compensate for any defective units that may need to be subtracted from your invoice.