4.1 Written Procedures
Written procedures are ordinarily developed and made available for the government representative's review,upon request. When the written procedures indicate use of this standard,they shall comply with the requirements of this standard and reference appropriate parts as necessary.
The extent of nonconformance of product shall be expressed either in terms of percent defective or in terms of defects per hundred units.
4.3 Formation and Identification of Lots or Batches.
The product shall be assembled into identifiable lots,sublots,batches,or in such other manner as may be prescribed.Each lot or batch shall, as far as is practicable, consisit of units of porduct of a single type, grade, class, size, and composition, manufactured under essentially the same conditions, and at essentially the same time. The lots or batches shall be identified by the contractor and shall be keep intact in adequate and suitable storage space.
4.4.1 AQL Use.
The AQL, together with the Sample Size Code Letter, is used for indexing the sampling plans provided herein.
The selection or use of an AQL shall not imply that the contractor has the right to supply any defective unit of product.
4.4.3 Choosing AQLs.
Different AQLs may be chose for groups of defects considered collectively, or for individual defects. An AQL for a group of defect may be chosen in addition to AQLs for individual defects,or subgroups,within that group. AQL values of 10.0 or less may be expressed either in percent defective or in defects per hundred units; those over 10.0 shall be expressed in defects per hundred units only.
4.5.1 Representative (Stratified) Sampling.
When appropriate, the number of units in the sample shall be selected in proportion to the sieze of sublots or sub-batches,or parts of the lot or batch,identified by some rational criterior When representative sampling is used, the units from each sublot,sub-batch or part of the lot or batch shall be selected at random.
4.5.2 Time of Sampling.
A sample may be drawn after all the units comprising the lot or batch have been assembled, or sample units may be drawn during assemble of lot or batch, in which case the size of the lot or batch will be determined before any sample units are drawn. If the sample units are drawn during assembly of the lot or batch, and if the rejection number is reached before the lot is completed, that portion of the lot already completed shall be rejected.
4.5.3 Double or Multiple Sampling.
When double or multiple sampling is to be used,each sample shall be selected over the entire lot or batch.
4.6 Inspection Procedures.
Normal inspection will be used at the start of inspection. Norma,tightened or reduced inspection shall continue unchanged for each class of defects or defectives on successive lots or batches except where the switching procedures given below require change. The switching procedures shall be applied to each class of defects or defectives independently.