Topic
Garment and fabric inspection guides: 4-point fabric inspection, inline and final inspection, AQL sampling, and the DHU and right first time measures.
Inspection is how a factory finds defects before the buyer does. This topic collects the notes on inspecting fabric (4-point fabric inspection and fabric defects), on the sewing line (inline inspection), at the end of production (final inspection and AQL sampling) and on the numbers that come out of it (DHU and right first time). The sewing defects guide describes what inspectors look for.
8 notes
The 4-point system scores fabric defects by length and converts them into points per 100 square yards. How to inspect rolls, assign points, calculate the score for a roll and a shipment, and what the result does and does not mean.
AQL sampling decides how many garments to inspect from a lot and how many defects are allowed. How the sampling tables work, inspection levels, code letters, accept and reject numbers, and what AQL does and does not guarantee.
DHU counts defects per hundred garments checked. The formula, how it differs from defective percentage, a worked example from end-of-line checking, and how to turn DHU data into action on the line.
A practical guide to common woven and knitted fabric defects: yarn defects, weaving and knitting defects, dyeing and finishing defects, and dimensional problems. What each looks like, where it comes from and how it is detected.
A final (pre-shipment) inspection checks a finished, packed lot against the buyer's requirements before it ships. What is checked, how samples are drawn, the order of work, and how to prepare so the lot passes the first time.
Inline inspection checks work at or near each operation while the line is running. How the traffic light system works, how to choose operations to check, sample sizes and frequency, and how to act on the results.
Right first time measures the share of garments that pass inspection without any repair. How to calculate RFT, how it relates to DHU and defective percentage, and how it is also used for lab dips, samples and shipments.
An overview of the sewing defects that cause most repairs and rejections, grouped by stitch, seam and assembly problems, with the usual causes and where to look first.