A pre-shipment inspection (PSI) is the last chance to catch a problem while the supplier can still fix it at their cost. Once the container is on the water, every defect is your defect. Here is how the inspection works and how to read the result.
When
A PSI is carried out when production is complete and at least 80% of the order is packed. Inspecting earlier means the last cartons are unverified; inspecting after loading means nothing can be changed.
How many units are checked
Inspectors do not check every piece. They use AQL (Acceptable Quality Limit) sampling: a statistically chosen number of units drawn at random from across the cartons, with the sample size set by the order quantity and the inspection level. The standard is well established and understood by factories, which matters — it makes the result hard to argue with.
What is checked
- Quantity — carton count and units per carton against the packing list.
- Workmanship — defects classified as critical, major or minor, each with its own acceptance threshold.
- Function — the product does what it should: switches on, holds pressure, fits together.
- Conformity — dimensions, colour, materials and markings against the signed reference sample and specification.
- Packaging — carton strength, labelling, barcodes, shipping marks, protection for transit.
Reading the report
A report is either pass, fail or pending. A fail is not a disaster — it is the system working. The usual responses are re-work and re-inspection, sorting out defective units, or a negotiated discount for minor cosmetic issues you are prepared to accept. What you should not do is release the balance payment on a failed report and hope.
The reference sample is everything
An inspection can only measure against something. If no signed reference sample exists, "conformity" becomes an opinion, and disputes follow. Zhoukun Group keeps a signed reference sample for every order and inspects against it, which is also why the sampling stage earlier in the process is not something to skip.
For clients in the healthcare and rehabilitation category, where product consistency is non-negotiable, an independent pre-shipment QC is standard on every order. For other categories it is strongly advised on any first order with a new supplier.