![]() ![]() – If the lot is accepted, it is commonly perceived that there is a maximum of 2.5% of defective units in the lot (with a failure risk percentage of less than 5%). – If the number of defective units is more than 10, the lot has to be rejected. According to Table A, the sample size corresponding to code “L” is therefore 200 units, and the corresponding acceptance number is 10. According to Table C, under General Level II, the sample size “Code” is L.Ģ. Let’s take a lot of 4,000 units to inspect, with an AQL of 2.5%.ġ. Table D. Proposed or common classification of defectives Example ![]() The following AQLs levels are usually applied by SBE unless client suggest others: DEFECTIVES Clients may indicate an specific Sampling plan, same as what defects are minor, major or critical according to the Acceptance Quality Level % they are willing to accept per type of defect. The above classification is not an Industry standard but a practical manner to classify defects in products. Minor: doesn’t reduce the usability/function of the product, but is a defect beyond the defined quality standard more or less reduces the sale of the products. Major: reduces the usability/function and/or sale of the product or is an obvious appearance defect. Product Defects considered for SBE inspections are usually classified within 3 categories: “Critical”, “Major” and “Minor” :Ĭritical: likely to result in unsafe condition or contravene mandatory regulation or reject by import customs. In the inspection process, one defective sample is counted one for the most serious defect only no matter how many defects found in the said sample. How defective products are counted or defined for the inspection?Īccording to ISO and the ASQ an Individual with Non-Conformances (defects) is called a Non-Conformant (defective) sample. Table C. See here the AQL Level table that displays from 0% to 6.5% defectived and the Acceptance and Rejection rate to be considered during a regular inspection. Please note that the arrows indicate a change in the Sampling Plan, where the sample size and the Acceptance and Rejection numbers will change as well. Table to define the sample size according to the Inspection Levels.Īfter potential defects are identified & classified before the inspection, inspectors shall follow the inspection plan in the next table to start inspecting the sampled goods. Three general and four special inspection levels are provided. How many pcs/units shall be inspected?Īccording to ANSI/ASQ Z1.4- 2003, the quantity of products to be inspected (sample size) is defined by the inspection level to be utilized and the lot size (quantity of product) in question. ![]() Guide to select between Normal and Special levels. You can use the following table as a quick guide to decide how to select a proper inspection level. Larger sample sizes are for inspection levels increasing from S-1 to S-4. Examples of this are inspections involving destructive or costly (time consuming) type inspection, or where large lots are involved, small sample sizes are desired and large risks can be tolerated such as repetitive processes (screw machine, stamping, bolting operations, etc.) performed by a quality supplier. Special Levels S-1, S-2, S-3 and S-4 may be used where relatively small sample sizes are necessary or large sampling risks can be taken.Unless otherwise specified, inspection Level II will be used. However, inspection of larger samples is required. ![]() Level III will give a lower risk of accepting a lot with excessive number of defects. Level III equals 160 percent of the amount of inspection Level II. Level I is required only 40 percent of inspection level II and can be used where less discrimination is needed. Level II is considered the norm (except for small sample sizes).
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