Inspect porcelain slabs before they are packed into the container, not after. Check a sample of slabs against the signed master sample for shade, surface and print, measure size, thickness and flatness, then check the packing, labels and loading.
Once a slab container is sealed, problems are expensive to fix. A broken or off-shade slab found at your warehouse means a claim, a delay and an unhappy customer. An inspection at the factory catches most of these while the plant can still replace them.
Before the inspection
- Send the inspector your specification, the approved master sample details, the grade definition and the packing list.
- Agree the sampling plan in advance. Many buyers base it on ISO 2859-1, as explained in AQL for tile inspection.
- Agree what counts as a critical, major or minor defect.
- Book the inspection when production is complete and before packing is sealed.
Visual checks
Slabs should be viewed upright or on a flat table under good, even light, from a normal viewing distance as well as close up. Look for:
- Shade against the master sample and between slabs of the same design.
- Print faults such as lines, banding, smudges or missing ink.
- Pinholes, bubbles, polishing marks or uneven gloss.
- Chipped corners and edges, cracks and scratches, including hairline cracks seen with side lighting.
- Body type on any cut or broken piece, if a full or colour-matched body was ordered.
Measurements
Flatness limits and the practical method are covered in large slab flatness tolerance.
- Length, width and squareness against the agreed work size and calibre.
- Thickness at several points on each sampled slab.
- Flatness with a straightedge and feeler gauges, against the limits agreed in your order.
- Weight per slab, as a check on thickness and on the loading plan.
Book-matched sets
For book-matched designs, stand at least one complete set side by side and check that the veins meet and the colours match. Check that the set numbers on the slabs match the crate labels. See book-match in porcelain slabs.
Packing and loading
- Frames or crates match the agreed type, with face protection, corner protection and tight strapping.
- Solid wood carries the ISPM 15 mark.
- Labels show design, size, thickness, grade, shade, calibre, batch, slab count and gross weight.
- Counts per design match the packing list.
- Frames are placed, braced and lashed in the container as the loading plan shows.
- Photos are taken of each frame in place and of the container seal.
The report
A useful report lists every check, the sample size, the defects found with photos, the measurements against limits, and a clear pass or fail. It should state any slabs replaced before loading. The full report structure is in what a tile pre-shipment inspection report should include.
Next step
We inspect slabs against your specification and master sample, supervise packing and loading, and send a photo report before the container leaves. To arrange inspection for your next order, book a free sourcing review.