Inspection Tests
On-Site Tests During a Product Inspection: What They Find
A product inspection is more than looking at goods. It also includes on-site tests: checks that use simple tools, or the factory's own equipment, to find problems a visual check misses. Which tests are worth running depends on the product, and each one has to be stated in the checklist before the visit. This guide covers the on-site tests most commonly used, what each one finds, and where its limits are.
- The tests that apply to almost every product
- Product-specific tests, and which categories they suit
- Why tests must be written into the checklist in advance
- What on-site tests cannot replace
Tests for Almost Every Product
A few checks belong in nearly every pre-shipment inspection, whatever the product:
- Carton drop test. Sealed export cartons are dropped on a corner, edges and faces in a set sequence. Then the cartons are opened and the contents checked. This is the most direct way to find out whether the packaging will protect the goods in transit. Drop heights in common procedures depend on the packed weight.
- Barcode scan. Barcodes on the product, retail packaging and cartons are scanned to confirm they can be read and that they encode the right number. A barcode that does not scan can lead to rejection at a retailer's warehouse.
- Carton weight and dimensions. Measured against the packing list and the shipping marks. Differences affect freight and can show missing or wrong contents.
- Product weight and dimensions. Checked against the specification, on several units.
- Function check. Every sampled unit is used the way the customer will use it: opened, closed, switched on, assembled, adjusted.
Product-Specific Tests
Other tests depend on the material and the type of product. The table shows the common ones and where each one is most useful.
| Test | What it finds | Typical products |
|---|---|---|
| Assembly test from the carton | Missing hardware, misaligned holes, unclear instructions | Flat-pack furniture, fitness equipment, bicycles |
| Stability and simple load check | Rocking, tipping, weak joints | Furniture, shelving, stands |
| Hi-pot and earth continuity | Insulation failure, poor earthing | Mains-powered appliances and lighting |
| Run test | Overheating, intermittent faults, noise | Motors, heaters, chargers, fans |
| Internal check (opening units) | Substituted components, poor wiring | Electrical and electronic products |
| Cross-hatch tape adhesion | Coating that will peel | Painted or coated metal, wood, plastic |
| Rub test with a white cloth | Colour that transfers | Textiles, leather, printed items |
| Moisture meter | Timber or packaging too wet at packing | Wooden products, cartons |
| Small parts, sharp edges, torque and tension | Choking and injury hazards | Toys and children’s products |
| Seam and trim pull check | Weak seams, buttons that come off | Garments, bags, soft toys |
| Needle detection | Broken needle fragments | Garments, soft toys, textiles |
| Smell check | Solvent or chemical odour | Plastics, foam, coated and leather goods |
Details by product type are in our guides to furniture, toys, small appliances and electronics and garments and textiles.
Write the Tests Into the Checklist
On-site tests only work if they are agreed before the inspection. For each test, the checklist should state four things:
- The method. Which procedure, drop height, voltage, number of rubs or force.
- The sample size. Usually smaller than the visual sample, because many tests are slow or destructive.
- The pass criterion. What counts as a failure.
- Who supplies equipment. The factory's hi-pot tester, light box or needle detector, or the inspector's own tools.
Agreeing this in advance has a practical reason as well. Destructive tests use up units, and a factory that was not told beforehand often resists on the day. A test written into the purchase order and the inspection checklist is a requirement. One proposed on the day becomes a negotiation.
Where the factory's equipment is used, the inspector checks its calibration record before relying on the result. A tester that has not been calibrated gives a number, but not evidence.
What On-Site Tests Cannot Replace
On-site tests are screening checks on a sample. They are good at finding defects that vary from unit to unit and changes from the approved sample. They do not replace laboratory testing. Chemical limits, flammability, fibre content, electromagnetic compatibility and full mechanical safety programmes need accredited labs and calibrated equipment that cannot be brought into a factory. Some material questions also need a lab, as our case study on a steel grade substitution shows. The two steels looked identical, and the difference was in the chemistry.
The report should state which tests were done, with what equipment and on how many units, and give the results. A pass that does not say what was tested is not a useful result.
For the visual sample size, use our AQL calculator. The tests above can be added to any SSTI product inspection when they are in the checklist.
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