Nine Majors Before Shipment
A garment unit in Guwahati has an export order for 1,200 men's polo shirts, shipped as a single lot. The buyer's quality manual specifies ISO 2859-1, general inspection level II, single sampling, normal inspection, AQL 2.5 for major defects and 4.0 for minor defects, with measurement faults classed as major. Three days before shipment, the buyer's representative inspects the lot. Nine pieces are classed major: three with skipped stitches on the placket, two with a 12 mm sleeve-length mismatch, two with chest measurement 15 mm outside the tolerance, one with a hole in a body panel and one with a twisted collar. Fourteen pieces are classed minor. The factory manager argues that "seven defects are allowed, we have only two extra", asks for the lot to be passed, and offers to 100% check the remaining pieces and re-offer them. The buyer's next inspection slot is in five days; the vessel booking is in four.
1. State what the sampling plan requires and whether the manager's "only two extra" reasoning is sound. What is the decision on the lot?
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Plan. Lot size 1,201–3,200 gives sample size code letter K at general inspection level II, so 125 pieces are drawn. For AQL 2.5 on code letter K, the acceptance number is 7 and the rejection number is 8. For AQL 4.0 the acceptance number is 10.
Result. 9 majors is above 7, so the lot is rejected on majors; 14 minors is above 10, so it is rejected on minors as well. The manager's arithmetic is correct and his conclusion is wrong. An acceptance number is not a quota of defects a process may produce; it is the boundary of a sampling plan designed to protect the buyer at the stated AQL. With 9 out of 125, the observed proportion is 7.2%, nearly three times the 2.5% AQL, and the unsampled 1,075 pieces are likely to carry a similar level. Seven allowed defects corresponds to about 5.6% of the sample - the plan is already generous at the limit.
Decision. The lot cannot be shipped as sampled. Screening 100% can find the visible faults, but it does not correct the process and it is not a pass: re-offered lots are a fresh submission, and a buyer may require tightened inspection. With a vessel booking in four days, agree in writing with the buyer: 100% screening against a defect classification list, a re-inspection, and air freight or partially split shipment if the second inspection also fails.
2. Build the corrective action plan: separate sorting from root cause, and say what happens if the next lot fails again.
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Sorting (short term). 100% inspection of the 1,200 pieces with a written defect list and a trained pair of inspectors, not the line operators who made the faults. Segregate by fault type so the counts mean something: placket skipped stitches, sleeve mismatch, chest measurement, holes, collar twist. Repair only where repair is invisible (re-stitch placket, re-set sleeve); reject the rest.
Root cause, by defect. Skipped stitches on the placket: needle size and point for the fabric, thread tension, hook-to-needle timing, operator speed; check the needle log and the seam strength. Sleeve mismatch of 12 mm: cutting or notching error, or a size mix on the line - check the marker and the bundle tickets. Chest out of tolerance by 15 mm: pattern or grading error, cutting allowance, or shrinkage after pressing; measure a pressed versus an unpressed panel. Hole in the body: needle damage or a snag at the cutting table. Twisted collar: interlining grain or fusing temperature.
System. Add an in-line check after placket and sleeve setting, a measurement audit every two hours on five pieces, a needle control policy, and a pre-production meeting with approved sample and tolerance chart. If the next lot also fails, ISO 2859-1 switching rules move the buyer to tightened inspection after two rejections in five consecutive lots, which raises the sample size and cuts the acceptance number.
3. The buyer offers to accept the lot if the unit pays for a third-party 100% inspection at the destination. Compare that with screening at the factory, given the four-day shipping window.
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Factory screening. Cost is internal labour for about 1,200 pieces, perhaps one to two days with two inspectors, and it keeps control of the repair loop. It also lets the unit record its own defect data and correct the line before the next lot. The risk is that self-inspection is not independent and the buyer may not accept it as evidence; a second failed inspection then leaves no time.
Destination inspection. It buys the buyer's acceptance, but it is expensive per piece, the unit pays for rejects plus freight both ways, and anything found at destination is repaired abroad or scrapped - usually far costlier than an in-house rework. It also leaves the unit with no data on its own process.
Practical combination for a four-day window. Screen in the factory now, with a buyer-agreed defect list and a joint count sheet; book the shipment; and offer to share the screening records and a pre-shipment AQL re-inspection at origin with the buyer's representative, who is already in the city. Ask for a written deviation covering the screening and the re-inspection result. If the buyer insists on destination inspection, price it into future orders rather than absorbing it on this one, and fix the placket station first, because three of the nine majors came from one operation.