AQL Levels: Your Ultimate Guide For Pre-Shipment Inspection Of Your Orders!
Ready to place your first order from China for your new business?
Overwhelmed to hear about a lot of new terms like pre-shipment inspection, product inspection, AQL, and inspection techniques?
Don’t worry; we will break down everything for you to understand before you perform product inspection on your own or hire a third party to perform it for you.
This article is our attempt to simplify AQL Standards and AQL Sampling for you and all entrepreneurs looking out for clear information on product inspection methods. After reading this article, you will know what exactly AQL means and why this method is preferred over other product inspection methods.
So let’s get started. We have divided the article into many sections to answer the most asked questions of the entrepreneur. It will help you easily navigate through your required information.
Following are the sections of the article:
- What is AQL(Acceptable Quality Limit)?
- Why AQL?
- How To Read AQL Tables And How Does It Work?
- AQL Charts And Inspection Standards
- Alternatives Of AQL Method
- AQL: Practical Implications
What Is AQL?
Acceptable Quality Level, Acceptance Quality Limit or AQL is defined as the worst tolerable quality level of a product lot to be accepted by the customer as a satisfactory product.
It is a method of product inspection that most companies adopt to check the quality of their manufactured lots. AQL of a product batch, lot, or shipment represents the maximum number of defective units the customer will tolerate.
Importers worldwide prefer to use different AQLs according to the nature of the product and defects types. Originally used by the US military during World War II, AQL standards have become commonplace in most international shipments of all product types: from clothes to medicines.
If we talk about Asian markets and China, specifically, ISO 2859-1 sampling and inspection tables define how the shipments and manufactured products are inspected for defects and international shipments.
If we draw a sampling plan having an AQL of 1%, a shipment having up to 1% non-conforming or defective product will be accepted by the customer. However, it is the maximum limit. The lower the non-conforming items, the better the product shipment.
Why is AQL preferred over other inspection methods?
Generally, the 100% Inspection Method is more efficient as the quality inspectors evaluate each unit in the lot or shipment. It ensures that the shipment conforms to international standards. But the downside of the full inspection method is non-practicality and lack of cost-efficiency.
The rationale behind using AQL for testing bullets by the US army was that if every bullet was to be tested in advance, no bullets would be shipped. And if no bullet was tested, it might lead to a catastrophe on the battlefield. Therefore, AQL acceptance sampling tables were then developed to help distinguish between acceptable and unacceptable batches or lots of bullets by taking random samples.
Therefore, AQL can be identified as an objective measurement of quality by the buyer or his representative. It ensures that the seller is not sending the products with too many defects. The limit to differentiate between too many defects and an acceptable lot is where AQL intervenes.
AQL Charts And Inspection Standards
Before you dive into the art of reading and understanding the AQL tables, you must familiarize yourself with the standards, inspection levels, and AQL levels in any industry.
Since the AQL method is used for almost all kinds of goods, ranging from clothes, medicines, and artillery to daily use products. Therefore, different inspection levels have been designed.
General Inspection Levels
There are three general inspection levels(Level I, II, III), and the levels let you choose the sample size out of specific shipment sizes. Each row represents a specific lot size, and columns show the inspection levels. The sample size is determined at the intersection of both.
Inspection level I(small sample size) is generally used when you have strict budgetary constraints, low-value products, or the supplier of products already has a strong TQM in place. Similarly, most importers use GII in the pre-shipment process because GII is a relatively cost-effective technique giving you appropriate ground for testing the products.
When to use GIII inspection because it corresponds to a large sample size?
Here are a few scenarios when importers prefer GIII:
- A poor history of suppliers regarding quality
- Placing first order with the supplier
- Newly developed product
- High-value product or high-risk product
Special Inspection Levels
When we talk about the special inspection levels, they’re four in number. Special inspection levels are usually not applied to a whole lot of products. Instead, it is used in combination with the general inspection level.
An example of how the Special Inspection level can be understood from the following illustration. For an order of 1500 plastic serving plates, the quality inspector will use 5 cups instead of 125 cups if you choose S1. Similarly, you can combine it with GII to check the plates for scratches, smudges, etc., and SI can check the dimensions of the outer carton.
Then comes the AQL levels!
Once you’ve chosen an inspection level and lot size, the corresponding sample size code has to be checked in the second table to appropriate the rejection or acceptance number of the defective units in each sample. ISO 2859 has defined different AQL levels that correspond to the rejection or acceptance number. Following are the three most common AQL levels that importers of consumer products use:
2.5% of major defects; major defects products are usually rejected by the end-user.
4% of the minor defects; the specifications are not completely met, and consumers usually accept the products at a discounted price or whatsoever.
0% critical defects are allowed in the sample size. These products are completely rejected and unacceptable from the consumer’s point.
The AQL levels are reflected in the AQL levels table as shown.
How To Read AQL Tables And How Does It Work?
The AQL tables are the statistical side of the inspection method and are treated as the industry standard for product inspections. The AQL charts help sellers, buyers, and third party representatives of buyers to determine the following critical elements about product quality:
How many units should the quality inspector choose from a given shipment?
What is the permissible or acceptable number of defective units in any shipment before the inspection fails?
These two questions are answered by using the AQL tables. AQL tables are important because the nature of products, manufacturing process, processing, etc., varies for different product types. Therefore, it is necessary to evaluate all factors and decide about the inspection level, sampling size, and AQL for any shipment.
To understand how to read an AQL table and how it works, we will proceed with the example of inspecting plastic cups shipment.
Assume that a buyer in the US has placed an order with a plastic cup manufacturer for 5000 reusable cups. Third-party pre-shipment inspection is a popular technique in China, so the seller also relies on third-party services.
Since we have already discussed what an AQL table helps you determine, let’s find the first question.
Sample size to be chosen from a given shipment size
Let’s have a look at the Sample Size Code Table below:
The table has General Inspection Levels and Special Inspection Levels codes given in the columns. Whereas the rows represent the size of shipment, batch, or lot. Let’s say the general inspection level for plastic cups is III.
The choice of inspection levels depends on your budget, lot size, product type, frequency of defects, and value of the product. Level I represents the lowest standard, and level III represents the highest one.
Since the lot size of plastic cups is 5000, we will correspond to the respective row of the table(3201-10,000). At the intersection of inspection level and lot size, we get the code for sample size. The code is associated with a specific sample size. It is represented in the second table of AQL.
In the table, each row represents a sample size code mentioned in the first table. It corresponds to the agreed-upon AQL level between the buyer and seller. The intersection point of two tells about the limit of accepting or rejecting a shipment lot based on the sample analysis.
In our example, the lot will be rejected if major defective units are 15 or more. On the other hand, the lot will be accepted if the major defective units are 14 or less.
AQL Method Vs. Full Inspection
AQL method is preferred for most consumer products by the importers over Full Inspection. The common reasons why the first one is preferred over the second are cost-effectiveness, time consumption, and practicality.
For instance, if a product lot of 20,000 units is inspected at AQL level II for 2.5, the sample size will be 315 units. The inspector can inspect 500 units a day, and the cost of one day is 299 USD. He will require 1 day to inspect the sample, and the cost will remain $299 and $0.015 per unit(quite minimal).
On the other hand, a full inspection of the lot will require 40 days, and the cost will elevate to $11,960, which means an additional cost of $0.6 per unit. Therefore, the AQL method is a more practical approach for seamless logistics without compromising product quality.
Frequently Asked Questions
What does AQL mean?
AQL or Acceptance Quality Limit is the worst tolerable quality level of a product lot to be accepted by the customer as a satisfactory product. Importers use AQL for determining the sample size and acceptance or rejection limits for shipments or products lots.
How is AQL calculated?
AQL is calculated by using different charts and tables as defined by the ISO 2859.
Why is Final Inspection important?
A final inspection is important to ensure that the products shipped do not have major defects. The process is important to assess you’re getting the same product as promised by the supplier. In short, the process helps to ensure that vendor has upheld his part of the transaction.
How Can We Help?
At GlobalTQM, we provide the buyers with some exceptionally convenient services to ensure that your products are safely shipped, and containers possess the same goods as promised to you. For the quality inspection and Container Inspection, you can buy our services that will be the best alternative to your own physical presence.
Container Loading Inspection focuses on the packaging of the goods to avoid in-transit damages, quantity disputes, etc. Check the details of the package and schedule a free call here:
Pre-shipment Final Inspection test products after mass production and ensure they are suitable for sale and meet all your requirements before the goods leave the factory. Check the details of the package and schedule a free call here:
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