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Sampling Method

We will offer professional inspection services for your goods according to globally recognized ISQC.Sample size of products will be randomly selected according to internationally recognized standards (MIL-STD-105E, ANSI/ ASQC Z1.4, ABC-STD-105, BS6001, ISO 2859, DIN40080).After sampling from mass goods, our inspectors will inspect the samples rigorously and carefully according to standards of AQL (Acceptable Quality Level).

AQL Overview

Download: ( AQL -sampling-chart.xls)

AQL namely Average Quality Level, is a parameter of the inspection. AQL is generally applied to inspections of export clothing/textile and daily supplies. AQL standards include AQL0.010, AQL0.015, AQL0.025, AQL0.040, AQL0.065, AQL0.10, AQL0.15, AQL0.25, AQL0.40, AQL0.65, AQL1.0, AQL1.5, AQL2.5, AQL4.0, AQL6.5, AQL10, AQL15, AQL25, AQL40, AQL65, AQL100, AQL150, AQL250, AQL400, AQL650, and AQL1000. Different AQL standards apply to inspections of different products. In AQL sampling, for the same sampling amount, the smaller values after AQL are, the fewer allowable defects there are, which means higher quality and relatively stricter inspections are required. Here are illustrations according to different AQL:
Inspection of products should be based on batch size, inspection level and sampling amount decided by AQL values and the quantity of acceptable qualified and unqualified products. The clothing quality inspection adopts single sampling plan, and acceptable quality level (AQL) of clothing batch size is 2.5. Adopt General Inspection Levels. Single sampling plans. See AQL-Sampling Chart for the sampling plans.
Example One: For an order of a batch of clothing of 3,000 pieces, 125 of them should be inspected randomly in accordance with AQL2.5 standards. It will pass if defective amount is no more than 7 and fail if defective amount is more than or equal to 8.
Example Two: For an order of 7 pieces, 5 of them should be inspected randomly in accordance with AQL2.5 standards. It will pass if there is no defective product and fail if there is one defective product; in accordance with AQL4.0 standards, only 3 pieces are inspected randomly and it will pass if there is no defective product.

How to establish reasonable AQL standards?

In accordance with AQL inspection standards, we can get maximum defects of sample size within an acceptable range.
Product defects found in inspection can be divided into three levels, namely Critical, Major and Minor.
The buyer and the seller should reach a consensus on the AQL level before producing. If there is no special instruction made by clients, Norm Inspection Service Co., Ltd. will usually adopt following AQL standards.

   Consumer Product

Critical defects

  no critical defect is accepted

Major defects

  AQL 2.5

Minor defects

  AQL 4.0

Clients can establish their own AOL standards. How to establish reasonable AOL standards for your products?
AQL is a dividing line indicating that whether product defects are acceptable or unacceptable, as well as a parameter related to the sampling plans. Here are some principles provided in order to determine appropriate AQL value. However, there hasn't been a method which can be applied to all different occasions yet.
Take uses of products and consequences caused by product failure into account. For example, for electronic components with the same standard, AQL value of those for general civilian equipment can be a little bit larger than those for military equipment, and AQL value of those for ordinary instruments can be a little bit larger than those for precision instruments.
Considering users, AQL value can't be too small, or it will lead to the increase in inspection fees and production costs, or frequent rejection of goods, causing losses to both buyers and sellers.
For goods in urgent need of the purchaser, in case that the producer finds it difficult to improve the quality temporarily, for the sake of timely receipt of the goods, a larger AQL value is needed properly. The AQL value will be adjusted after the producer's quality is improved.
In case that there are a lot of product parts, and unqualified parts can be found and replaced with qualified parts easily in assembly and maintenance, the AQL value can be a little bit larger and vice versa.
Considering the assembly sequence, if product defects of the previous process will result in a waste of time and cost of the following process, the AQL value of the previous process should be smaller than that of the following process.
When establishing the AQL value, take a compromise between the ideal quality of consumers and the quality level which may be provided by the producer into account, namely, the compromise quality between the quality which is desired by consumers and the quality they can afford. The stricter the quality requirements are, the higher production and inspection costs there will be. Moreover, these costs are counted in products' costs ultimately.
For some household appliances, clothing and daily consumer goods, if poor performances as well as possible security risks caused by unreasonable design structure, manufacturing process, and raw materials of products occur, the AQL value should be smaller; as for those defects which only affect appearances of products, such as scratches and spray painting, a larger AQL value is available.


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