Ceramics fail in ways that are invisible until the carton is opened: a hairline crack from a fast cool, a glaze that crazes after a winter outdoors, a shade that drifts between kiln loads. This page sets out where those failures are caught, and what the acceptance standards actually are.
A single inspection before loading finds problems after they have already been paid for in labour, glaze and kiln time. The factory works to three gates so that defects are caught while they are still cheap to fix.
Clay body, glaze raw materials and packaging are checked against retained standards on arrival. Moisture content in the body and particle size in the glaze are the two variables that cause most downstream defects.
First-off approval on every mould and every colour change, then patrol checks through the shift. This is where warping, mould wear and glaze thickness drift are caught before a full kiln load is committed.
AQL sampling on the finished, packed order. Cartons are opened at random, pieces are inspected on all visible surfaces, and the packing itself is checked because most transit breakage is a packing failure, not a pottery failure.
| Check | Method | Acceptance |
|---|---|---|
| Glaze defects (pinholes, crawling, blistering) | Visual, 800–1000 lux, arm length | No defect visible on the display surface |
| Colour match | Comparison to retained master chip | No perceptible difference in daylight |
| Warping | Flatness on a granite surface plate | Gap under 1.5% of the rim diameter |
| Drainage hole | Go / no-go pin | Present, clear, correct diameter |
| Foot ring | Visual and touch | Flat, no sharp edge, sits without rocking |
| Crazing | Visual after 24 h in water | None on food-contact or outdoor ranges |
| Chips and cracks | Visual, all surfaces | Zero on the display surface |
The display surface is defined per shape and written into the purchase order. A pot has one face the customer sees on the shelf and one face against the wall; treating every square centimetre as display grade doubles the reject rate and the price without improving the product.
These are not run on every order by default, because each one costs money and time. They are quoted as line items when the destination market or the buyer requires them.
| Test | Standard | Typical reason |
|---|---|---|
| Lead and cadmium leaching | FDA 21 CFR 175.300 / EU 84/500 | Planters for herbs, or US retail requirements |
| Cold crack resistance | Thermal shock, 0 °C to 60 °C cycles | Outdoor range in a continental climate |
| Drop test, packed | ISTA 3A or 1A | E-commerce and parcel network shipping |
| Carton compression | ASTM D642 | Pallet stacking in a warehouse |
| REACH SVHC screening | EU REACH candidate list | EU import documentation |
| RoHS and battery transport | EN 62321 / UN38.3 | Smart planter electronics |
| Surface wear | Taber abrasion on glazed tile | Contract and hospitality projects |
Inspection follows ISO 2859-1 general inspection level II. For an order of 2,000 pieces that means 125 cartons or pieces sampled, with acceptance at AQL 2.5 for major defects and AQL 4.0 for minor ones. Major means the product cannot be sold or will fail in use; minor means it is visible but does not affect function.
| Order quantity | Sample size (level II) | Accept at AQL 2.5 | Reject at |
|---|---|---|---|
| 151–280 pcs | 32 | 2 | 3 |
| 281–500 pcs | 50 | 3 | 4 |
| 501–1,200 pcs | 80 | 5 | 6 |
| 1,201–3,200 pcs | 125 | 7 | 8 |
| 3,201–10,000 pcs | 200 | 10 | 11 |
Buyers can appoint SGS, Bureau Veritas, TÜV, QIMA or a local inspection company to attend the pre-shipment check. The factory books the slot, prepares the goods in a dedicated area, and provides the packing list and the approved sample for reference.
A ceramic pot that survives a pallet but not a parcel network is a packing failure. For e-commerce and dropship orders the carton is designed around the pot, not chosen from a catalogue: moulded pulp or honeycomb inserts hold the rim and the base, the pot never touches the carton wall, and the box is drop tested at 1.2 m on a corner, an edge and a face.
The failed points become a rework list. Sorting and re-glazing where possible, replacement from stock where not. The order is re-inspected on the failed points and photographed before booking, and the delay is absorbed into the shipment schedule rather than pushed onto the buyer.
For bulk pallet shipments, up to about 5% is accepted in the trade and priced in. For parcel and e-commerce shipments the target is under 1%, achieved through the insert design and a drop-tested carton rather than a thicker box alone.
Yes, and it is encouraged on first orders. Give five working days notice so the goods are complete and packed. The factory provides the packing list, the approved sample and a dedicated area for the inspection.
Where a test has been commissioned, the report is issued against the order and travels with the shipping documents. Routine orders ship with the inspection report and the packing list; leaching, REACH and drop tests are quoted separately because each carries a lab fee.
Tell us the destination market and how the product will be sold. We will confirm which tests apply and what the acceptance criteria should say.