1.6 MIL-STD-105D AND ANSI/ASQC Z1.4-1981





• Began development 1942


• A set of tables for single, double and multiple inspections.


• These tables are designed to favor producers risk.


• Three types of inspection levels,


(III) Tightened - for new suppliers, or suppliers with poor quality history

(II) Normal - for poor quality history

(I) Reduced - for suppliers with a good quality history


• AQL (Acceptable Quality Level) - chosen by experience and requirement



1. Sample size code can be found on table (pg. 329) using lot size and inspection level.



2. Using AQL, and sample size code, find the appropriate sample plan table, and look up the values. (plan varies by single, double, multiple sampling)



- see page 336 for a multiple sampling plan.


3. Start at normal inspection level, then tighten or loosen as required.



• An example of use for these tables is an aerospace manufacturer is receiving batches of parts in batches of 5000. These parts will be used in the landing gear, and are considered critical. Find sampling plans (single, double, and multiple) for this batch. Find a single sampling plan if the two last batches were rejected.


READING: chapter 9, pg. 325-338

PROBLEMS: pg. 379 #1, 3, 5


1.6.1 Practice Problem


1. Given a lot of 3000 and an AQL of 1%, compare level I, II, and III plans using OC curves on the same graph.