Types of inspection
- Pre-production inspection: checks raw materials and components before production starts.
- During production inspection: catches problems when 20 to 60% of the order is made, while there is still time to fix them.
- Pre-shipment inspection: a random sample of finished, packed goods, checked against your specification. This is the most common type.
- Container loading check: confirms quantities, carton condition and correct loading.
How AQL sampling works
AQL (acceptance quality limit) sampling, based on ISO 2859-1, sets how many units to check and how many defects are acceptable. Inspectors usually use general inspection level II, with common limits of:
- 0 for critical defects (unsafe products)
- 2.5 for major defects (product unsellable)
- 4.0 for minor defects (small flaws)
Example: for an order of 3,000 units at level II, the sample size is 125. At AQL 2.5, the lot passes with up to 7 major defects and fails at 8. At AQL 4.0, it passes with up to 10 minor defects and fails at 11.
What a good inspection checks
- Quantity, packing and carton markings
- Appearance against the golden sample
- Measurements and weights
- Function and safety tests
- Labels, barcodes and compliance markings
- Drop test of packed cartons
If an inspection fails
Do not release the balance payment. Agree on rework or replacement with the supplier, then book a re-inspection. A clear written specification makes these talks much easier.
Frequently asked questions
What does AQL 2.5 mean?
It is the acceptance quality limit used for major defects. For a given sample size, it sets the maximum number of defective units allowed before the lot fails. For example, a sample of 125 passes with up to 7 major defects.
When should a pre-shipment inspection happen?
When production is complete and at least 80% of the goods are packed, so the sample represents the real shipment.
