Statistical Variable Acceptance Plans for Transverse Chemical Skew in Wet Processing
Variable acceptance plans under ISO 3951-1 quantify transverse wet-processing skew through across-width chemical assay data, preventing border detentions.
Lot Acceptance
Approval Decision
A formal quality decision process determines whether an entire production batch of textiles is approved for shipment or rejected. In the garment trade, lot acceptance depends on whether the sample specimens extracted from the batch meet the predetermined limits for both physical properties and visual defects. This checkpoint protects the buyer from receiving substandard goods while providing the mill with clear criteria for product release.
Sampling Framework
The evaluation uses statistical sampling plans to inspect a representative portion of the shipment instead of checking every single yard. For visual defects, the inspector counts the major and minor flaws in the chosen rolls and compares them to the acceptable quality limit. For physical tests such as pilling resistance or fabric weight, the average laboratory result must fall within the allowed tolerance range to secure lot acceptance.
If the sample’s defect count or measured variance falls below the critical threshold, the entire batch is officially released for distribution.
Statistical Standard
When a lot fails to meet these criteria, it is put on hold for reprocessing or sorting to remove defective units. The manufacturer must then decide whether to scrap the batch, sell it as second-quality material or negotiate a discount with the buyer. This risk management tool prevents defective fabric from entering the garment cutting room, which would otherwise result in high sewing defect rates.
Assessment Boundary
This decision model assumes that the samples tested are truly representative of the entire manufacturing run. If the sampling is biased or if the batch is highly non-uniform, the statistical model fails to protect either party. For this reason, standard operating procedures dictate that samples must be pulled from random locations throughout the delivery.