What is AQL, AQL Sampling Standard?

In modern quality management systems, AQL (Acceptable Quality Limit.Acceptable quality limitsSampling standard is an important tool in the field of foreign trade inspection, about 90% of foreign trade products will be based on international standards for AQL sampling inspection. It plays a key role in international trade through scientific sampling methods and judgment rules, providing buyers and sellers with an objective basis for quality assessment.

AQL, or Acceptable Quality Limit, is the maximum percentage or number of defects that a buyer can accept in a sample inspection. It is essentially a quality threshold set based on the principle of probability in batch product inspection, which is used to help buyers determine whether a batch of goods meets the acceptance criteria.

1. Fatal defects:

Such defects can cause the product to fail to function properly and even pose safety hazards. Like the risk of electrical leakage in electrical products, it is a fatal defect that may pose a threat to the life and safety of the user.

2. Serious defects:

Significant impact on the function or appearance of the product, which may trigger customer returns or complaints. For example, the product functions abnormally in use.

3. Minor defects:

Smaller impact on product use or appearance, but may affect customer satisfaction. For example, small threads on clothing or slight dirt on the surface of daily necessities type, although it does not affect the basic use of the product, but it will reduce the consumer's goodwill towards the product to a certain extent.

AQL values are usually expressed as a percentage or ratio and range from 0.065% to 4.0%. The determination of specific values is closely related to product characteristics and industry standards. When applying AQL, it is often necessary to combine it with an international standard (e.g. ISO 2859) to developsampling plan.. The program contains the following main elements.

1. Inspection lot size:

That is, the total amount of product to be inspected, which is the basis for determining the sample size.

2. Sample size:

The number of samples to be taken is calculated based on the test batch size and the corresponding criteria.

3. Number of acceptable and rejected defects:

Specify the number of passing judgments (Ac) and the number of failing judgments (Re) that are allowed to exist in the sampled sample. If the number of defects in the sample is less than or equal to Ac, the lot is accepted; if it is greater than or equal to Re, it is rejected.

AQL sampling standard is based on mathematical probability principle of random sampling inspection method, can be calculated according to the total amount of goods sampling volume, and give different goods in the amount of acceptance or rejection of non-conforming products, for product quality to provide a notarized assessment of the guidelines. The following are some of the major international standards.

• ANSI/ASQC Z1.4: Developed by the American National Standards Institute (ANSI) and the American Statistical Association (ASQ), the full title is "Sampling Procedures and Forms for Inspection by Attributes."

• MIL-STD-105E: This is a sampling inspection standard developed by the U.S. Department of Defense, known as "Military Standard 105E - Sampling Procedures and Forms for Inspection by Attributes".

• BS 6001: A sampling inspection standard published by the British Standards Institution (BSI) for sampling inspections during production and manufacturing.

• ISO 2859: A set of quality management standards developed by the International Organization for Standardization (ISO), known as "Sampling Procedures for Inspection by Attributes", is the most commonly used sampling standard in international trade, especially in the manufacturing industry, and has wide international acceptance.

• GB/T 2828.1: Chinese national standard, formally known as Counting Sampling Inspection Procedure Part 1: Lot-by-Lot Inspection Sampling Plan for Retrieval by Accepted Quality Limit (AQL). The standard provides enterprises with a set of quality control procedures based on sampling inspection, which is applicable to quality inspection in mass production.

The selection of an appropriate AQL sampling standard requires a combination of factors to ensure that it meets the quality requirements as well as the practical needs of production and trade.Inspection OnlineRecommendation:

Quality requirements vary greatly across industries and products. For high-risk products such as medical devices and aerospace, strict AQL standards, such as lower AQL values and stricter sampling plans, should be chosen to minimize quality risks, while grocery products such as textile and clothing, furniture, and kitchenware can be chosen to have AQL 2.5 or 4.0, and electronic and electrical products can be considered to have AQL 1.5 or 4.0.

In order to avoid trade disputes, buyers and sellers should explicitly agree on the AQL value andinspection of goodsStandards. Both parties need to negotiate and reach agreement according to the actual situation of the product and their respective needs to ensure the fairness and operability of the test standards.

In high-risk industries, it is recommended to adopt C=0 standard or lower AQL value to strictly control the product quality and reduce the loss due to quality problems; while for lower risk industries, the AQL standard can be appropriately relaxed.

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As an important tool for quality management, AQL sampling standards provide strong support for product quality control and international trade through scientific systems and rigorous standards. Enterprises should fully understand the core elements of AQL sampling standards in practical application, and reasonably select and use AQL sampling standards in combination with their own needs and actual situation to ensure the smooth development of product quality and trade.