Earlier this week I was with a client, during one of their China trips. They import garments, and one of the most important criteria is the respect of size charts. If measurements are out of tolerances, the garments might be uncomfortable… or even unwearable.
One supplier was asking “if some samples are inside the tolerance, and others are out of the tolerance, how do you decide if the order is not acceptable?”
It is a good question. After thinking about it for some time, I see two ways of doing:
-1- Stick to the usual inspection statistics
Description: the inspector simply follows the AQL tables. Measuring all the samples selected for visual inspection might take too long, so we would adopt a “special” inspection level (S-2, S-3, or S-4) and a specific AQL level (e.g. 4.0% maximum for the number of samples out of tolerance).
Advantage: the supplier cannot criticize the pass/fail decisions, as long as he agrees on the measurements taken by the inspector.
Drawback: sometimes all the garments in one size are out of tolerance, and the other sizes are within the tolerance. In this case, the one or two bad sizes might be accepted anyway, if the “good” sizes compensate.
-2- Take decisions size by size, not for the whole order
Description: the inspector checks a few samples (say, 3 pieces per size and per color). If he finds one piece out of tolerance, he checks more samples in that precise size/color and on the same measurement point. This size is refused if a second “bad” piece is found during this process.
(These numbers should be adapted to each situation; buyers can also set a maximum percentage of “bad” samples. The important is to have some type of rule.)
- As described above, the importer does not run the risk of receiving a few sizes that cannot be delivered to the stores.
- During re-inspections, the inspector can focus on the size/color he has rejected (in more depth), instead of re-checking everything.
- In case there are many sizes (e.g. a brassiere in 10 sizes and 3 colorways) and most products are out of tolerance, the inspector might not have enough time to check everything he should.
- Unscrupulous inspectors might write only good measurements, just to avoid checking more samples.