Pre-Shipment Inspection Guide: AQL Explained and a QC Checklist

What is pre-shipment inspection and when is it done?

Pre-shipment inspection (PSI) means an independent inspector visits the factory once production is finished and most of the goods are packed, selects random samples and examines them against the approved sample and product specification. The general practice is to inspect when at least most of the order is packed, so that the selected samples truly represent the lot to be shipped.

PSI is not the only step in quality management. For larger or more complex orders, a raw material and first-article check before production (IPC), a mid-production check (DUPRO) and a loading check during container loading may also be carried out. Which checks you need depends on product risk, order size and your past experience with the supplier. It makes sense to use these steps more often on a first order with a new supplier.

• IPC: pre-production raw material and first-article check
• DUPRO: during-production check
• PSI: final pre-shipment inspection
• Loading check: supervision of container loading and sealing

What is AQL? The sampling logic in pre-shipment inspection

Checking every single unit of a lot of thousands of products is usually not practical. AQL (Acceptable Quality Limit) is a statistical sampling method based on international standards such as ISO 2859-1. Depending on the lot size and the chosen inspection level, a table determines how many units will be inspected and the maximum number of defects allowed in that sample.

In practice, general inspection level II is used most often. For a given lot, the table specifies a certain number of units to inspect and, according to the chosen AQL value, gives an “accept” and a “reject” number. If the number of defects found in the sample is equal to or below the accept number, the lot is accepted; if it reaches the reject number, the lot is rejected. The value of this system is that the decision rests not on personal impressions but on an objective rule agreed in advance.

AQL values are set separately for each defect class and should be written into the contract or inspection instructions. Which values are appropriate depends on the product type, target market and your customer’s expectations. In safety-sensitive categories such as children’s or electrical products, it is common practice to allow zero tolerance for critical defects.

Critical, major and minor defects: how classification works

Critical defects are those that may threaten the user’s health or safety or breach legal requirements: sharp edges, small parts that could be swallowed, electrical insulation faults and the like. Major defects are problems that seriously affect the product’s function or saleability: a mechanism that does not work, a clear dimensional deviation, the wrong colour or a broken part. Minor defects are small cosmetic flaws that do not make the product unusable but lower the perception of quality.

To prevent classification from causing disputes, the best method is to prepare a defect list specific to your product. In this list, each type of defect is defined, with photo examples, stating which class it falls into. In a textile product, for example, a skipped stitch might be defined as major and a small loose thread end as minor. When the list is translated into Chinese and shared with the factory in advance, the production team also knows clearly what to watch for.

Pre-shipment inspection checklist: what is examined?

The inspection starts with quantity and packaging before the product itself. The inspector compares the number of cartons ready for shipment with the order quantity, opens randomly selected cartons and checks carton markings, barcodes and inner packaging. The products are then inspected visually, dimensions and weight are measured, colour is compared with the approved sample and product-specific functional tests are carried out.

Additional tests can be added depending on the product: a drop test, a simple rub test for colour fastness on fabric, safety and operation tests on electrical products, leak tests on products with lids, or assembly tests on products that need assembling. Writing which tests are to be performed and their acceptance criteria into the inspection instructions ensures the inspector applies your expectations precisely.

• Quantity and carton count
• Carton markings, barcodes and labels
• Visual check and defect classification
• Dimensions, weight and colour comparison
• Functional and product-specific tests
• Packaging strength and drop test

How to prepare inspection instructions: the precondition for a good inspection

The inspector’s job is to apply on site the quality expectation you have defined. The clearer the inspection instructions, the more valuable the report. The instructions should include the product specification, photos of the approved sample, dimensional tolerances, colour references, packaging and labelling requirements, tests to be performed, AQL values and the product-specific defect list.

Sharing the instructions with the supplier in advance is also important. When the factory knows which criteria will be checked, it carries out its own internal checks to the same criteria and the risk of rejection falls. The inspection date should be planned for a day when the factory is genuinely ready; otherwise the inspector finds a half-packed lot and the inspection may have to be repeated.

Keeping the approved sample sealed at the factory gives the inspector a concrete reference for comparison on inspection day. If the sample is not at the factory or was revised during production, photos of the final approved version and the revision notes must be added to the instructions. For characteristics such as colour and texture that photos cannot fully convey, using physical references like a Pantone code, fabric swatch card or material piece minimises differences of interpretation on site and increases the report’s reliability.

How to read an inspection report and what to do if it fails

A good inspection report includes the overall result (pass, fail or pending), the sample size inspected, defects found by class, measurement results and photos for each finding. When reading the report, look not only at the overall result but also at the type of defects and whether they recur. The same defect appearing on many units may point to a systematic production problem and calls for a root-cause discussion with the supplier.

If the result is a fail, assess the options calmly: the factory sorting the whole lot and replacing defective units, carrying out a specific rework, or partially remaking production. A re-inspection is then scheduled. Having tied the balance payment to the inspection result gives you a strong position in this discussion. Recording all agreements in writing prevents the same problem from recurring on the next order.

After a negative result it is good practice to ask the supplier for a written corrective action plan. The plan should state the root cause, what measures have been taken, how sorting will be done and which control steps will be added to prevent recurrence. The plan is also passed to the inspector for the re-inspection, so the inspector checks not only the defect count but also whether the measures have been implemented.

Loading checks and pre-shipment inspection with Yeni İpekyolu

Even if the PSI result is positive, you should not overlook problems that can occur during loading: missing cartons, unapproved lots slipping in, or cartons stacked in a way that damages them. In a loading check, the inspector records the container’s condition, the number of cartons loaded and a random check of products, then photographs the sealing. These records are also useful for customs and insurance.

At Yeni İpekyolu, with our teams in and around Guangzhou, Shenzhen, Yiwu and Shanghai, we deliver pre-production, during-production, pre-shipment and loading inspections with reports in Turkish. We prepare your inspection instructions with you, translate the defect list into Chinese and, if the result is negative, follow the correction process with the supplier on site. Contact us if you would like to plan a pre-shipment inspection for your next order.