Process Drift Control and Chemical Indicator Testing on Repeat Orders
Process drift on repeat textile orders requires mill-floor indicator testing backed by statistical skip-lot laboratory verification to prevent RSL border holds.
ISO 2859-1 AQL
Sampling Standard
Acceptance quality limit for garment inspection provides the numerical benchmark against which a random sample of finished goods is evaluated to determine the statistical probability of defects. ISO 2859-1 AQL identifies the specific sampling plans and the decision rules used by quality control teams to accept or reject a production lot. It governs the balance between the risk of a buyer accepting poor quality and the risk of a supplier having a good lot rejected.
This standard applies to the final inspection of apparel, home textiles, and footwear before they are shipped from the factory.
Mathematical Basis
The system uses a set of tables to determine the number of items that must be inspected based on the total size of the shipment. ISO 2859-1 AQL defines three levels of general inspection and several special levels for tests that are destructive or expensive. For a standard order, the inspector typically selects level two, which provides a moderate degree of protection for the buyer.
Once the sample size is determined, the tables provide an acceptance number and a rejection number for different quality levels. For example, a limit of 2.5 means that the batch is accepted if the number of defective units found is below a certain threshold. If the count of defects reaches the rejection number, the entire shipment is considered a failure and must be 100 percent re-inspected by the factory.
This statistical approach assumes that the quality of the sample represents the quality of the whole batch. It provides a clear and objective way to make decisions on the factory floor without having to check every single item.
Inspection Level
The choice of the specific limit depends on the type of defect and the requirements of the brand. Defects are usually categorized as critical, major, or minor, with different limits applied to each. Critical defects like a needle left in a garment have a limit of zero, meaning the whole lot is rejected if even one is found.
Major defects like a hole in the fabric or a wrong shade have a slightly higher limit, such as 1.5 or 2.5. Minor defects that do not affect the function of the garment, such as a loose thread, might have a limit of 4.0. The use of iso 2859-1 aql allows the buyer and the supplier to agree on these levels before production begins.
This agreement reduces the chance of disputes during the final inspection. The standard also includes rules for switching between normal, tightened, and reduced inspection based on the past performance of the supplier. If a factory consistently produces high quality, the number of items checked can be reduced to save time and money.
Conversely, if quality fails, the inspection becomes more rigorous.
Acceptance Limit
The effectiveness of the protocol relies on the randomness of the sample selection and the skill of the inspector. ISO 2859-1 AQL does not guarantee that every garment in an accepted lot is perfect, but it does guarantee that the percentage of defects is unlikely to exceed the chosen limit. It is a tool for managing risk rather than a method for ensuring absolute perfection.
The boundary of the standard is the point where the inspection is completed and the results are recorded. It does not cover the process of repairing the defects or the subsequent re-inspection of a failed lot. The results are only valid for the specific lot that was sampled and cannot be used to predict the quality of future orders.
Proper documentation of the inspection process is required to maintain the traceability of the quality decisions. The final report must state the lot size, the sample size, and the number of defects found for each category.