What AQL Means? How Acceptance Quality Level Helps in QC Inspection?
September 28th, 2021
What is Quality Acceptance and Acceptance Quality Level?
How to make sure that the products you received reach the quality level which you want?
Well, the thing is, nowadays, more and more people are starting e-commerce businesses. And that means the process of checking the quality of products is becoming harder because the idea of quality varies from person to person.
So, to help with this step and to make the quality acceptance an easy process, there are multiple QA inspection methods, one of which is known as AQL (Acceptable Quality Limit).
We have compiled a guide, it contains information about what Quality Acceptance is and how you can follow the rule in order to check the quality of products. We have added the steps of QA and AQL along so that you can get the most out of the business.
Chapter 1: What is Acceptance Quality Level? Why it is Important for Your Business?
Quality acceptance is a crucial step in the business of e-commerce because it defines the pillars of the business. However, it can become a headache for new people because of difficult steps.
In this chapter, we are going to explain what is Quality Acceptance and how it is related to AQL.
1. What do Acceptance Quality Level and Acceptance Quality Limit mean in simple terms?
In the step of quality acceptance, you will hear the term AQL. But, what is AQL? The full form of AQL is Acceptance Quality Limit, it is used to check the quality of the samples or the lot itself.
In simple words, it is the maximum limit of a quality level that can be tolerated.
To make you understand this term, let’s assume that you are starting the business of socks. You have placed an order with the supplier. When the supplier sends you the samples, you deliver those to a quality acceptance agency.
Now, the agency will test the samples, and if the defective samples are higher than the acceptable limit, they will label the whole lot as defective. There are certain rules and parameters of quality acceptance and AQL.
What happens is the agency assumes that if 30 out of 50 products are defective, that means the whole lot is defective.
2. Advantages and disadvantages of having an Acceptance Quality Level
Advantage of having an Acceptance Quality Level
AQL step has a lot of advantages. However, these advantages are related to different product types. Some of the common advantages that EJET has seen are as follows.
Less time taking
One of the most prominent features of the AQL checking method is that it takes very little time. That is because people send the whole batch and it takes a lot of time to check each and every sample.
With the AQL method, a check is applied to sample testing. If the maximum number of samples is not matched with that criteria, the whole lot is considered defective. In quality acceptance, AQL is considered the best method because of this main reason.
Clean inspection results
Another common feature of AQL is clean and clear inspection results. See, the thing is AQL step is followed with the help of statistics. It provides a clear result of how many samples have passed through the testing procedure.
With this statistical data, you make a clear decision if the inspection is failed.
Lastly, AQL is a cost-effective solution. We can link AQL with the time-taking point. See, as the testing takes less time, it makes it more feasible in terms of money.
In simple words, if you want the QC team to check 1000 samples one by one, they will take a hefty charge for it.
Disadvantages of having an Acceptance Quality Level
We all know that with advantages, there are disadvantages also. Here, we will talk about the downsides associated with the AQL step process.
Leaving issues outside of inspection parameter
There is a chance that the supplier has placed defective items in the whole lot that were not present in the samples.
Yes, it can be avoided by tightening the parameters of AQL inspection. However, it can happen. This leads to defective products passing through quality acceptance.
Yes, the AQL step process is faster than other testing methods. However, it still takes time. For instance, checking a particular AQL lot size takes 3 days (depending on the agency). It can become an issue if you have a tight shipping deadline.
3. Is the Acceptance Quality Level important in the business?
One thing is for sure, if you are in the business of e-commerce, there is a need to have someone who can check the quality of products for you.
As for the AQL step process, we recommend you to use this method, because it has multiple advantages compared to other quality acceptance methods.
We would like to conclude this chapter by saying that AQL is an important step in the e-commerce business. For the reason that it enables you to check the quality of whole lot size without spending that much time and money.
Chapter 2: Must-know about Acceptance Quality Level – How to Apply it in Your Business?
Now that you have an idea about the AQL is and whether it is important in the business of e-commerce, let’s talk about how you can apply it in the business.
Applying the knowledge of AQL requires one to have basic knowledge of terms and words used in AQL. Let’s talk about the whole process in detail, so that you can use this in the inspection phase.
1. 3 categories of defects related toAQL inspection
In AQL, the instances that are failed and are not able to meet the quality are known as defects. These defects are further divided into three main parts and those parts are mentioned as follows.
The first type of defect that is considered when inspecting a product lot is a critical defect. Critical defects are known as defects that can harm users.
For instance, let’s say that an inspecting agency is checking a battery-powered toy. If they have labeled this toy in a critical defect that means, it can cause a choking hazard, or the battery can explode due to heating.
Major defects are defects that are not acceptable to the end-users. In simple words, the customers who want the product will notice this and will return the product.
An example of this type of defect can be related to a shirt design. If you are doing the business of famous brands like Nike, the customers will return the shirt if the logo is not in place or has faded colors.
The last type of defect is a minor defect. You can take a guess by the word that it will not affect the sales in major proportion. To help you understand, a minor defect is one that does not reduce the usability of the product.
Let’s say that, a toy has a little thread at the back. Other than that, the whole toy works effectively. The quality acceptance agency will label it as a minor defect, because it is not affecting the usage and will not harm the user in any possible way.
2. 3 factors of AQL to understand before the AQL table
The inspection that determines the level of quality is called an AQL table. AQL table has all the factors that enable the inspection phase.
Most of the time, an AQL table consists of terms such as lot size, inspection level, and AQL limit. Don’t worry we are going to explain these terms so that you can understand the table easily.
The first thing that you will see in the AQL table is Lot size. On the leftmost side of the table, you will be able to see.
The lot size refers to the total quantity. We can say that it is the starting point in the table where the numbers are the quantity of the products you are sending.
The lot size is the easiest part of the table. Let’s say that you are sending 400 pieces of toys, you have to select the range of 281-500 from the table.
The next thing that you will see in the AQL table is the inspection level. It is right next to the lot size column. The inspection level is divided further into two main categories, include general inspection level and special inspection level.
General inspection level
The general inspection level is the one where Quality Acceptance offers to inspect the main sample of all SKUs (Stock Keeping Units). This inspection level is usually done by looking at the product or doing on-site tests.
An example of a general inspection level is checking the packaging, assembly, and manuals of phones.
The general inspection level is further divided into three main categories that range from I, II, and III. I am linked with the smallest lot size.
We can say that it is a budget option for new business. III is for the lot that has a large quantity and is the tightest inspection level in the general category. It is also expensive compared to the other two.
II comes in the middle of the category and is used by most people because it covers all essential parameters of the I and III category.
Special Inspection Level
The special inspection level is the second type of inspection level in the AQL table. These tests are conducted in a controlled environment and on a small number of samples.
The reason for that is special tests can destroy the item. Plus, the special inspection level is expensive and they give similar results on all samples. That is why the tests are done in small quantities.
Special inspection level is divided into four types and that are S1, S2, S3, and S4. S1 offers a small sample size whereas S4 has the largest sample size.
The last item on the table of AQL is the AQL limit. AQL limit is ranged from 0% to 15% and that shows the lowest tolerance for the defects.
We talked about the defects and types of defects in the above section. The defect label is decided on the percentage of tolerance that you can get from the AQL limit given in the table.
For consumer goods, QC agencies recommend an AQL of 0, 2.5, and 4 percent for critical, major, and minor defects. For instance, if your sample size lies at 2.5, using the table they will say it has major defects. That is how the table works.
3. 2 tables of AQL you need to know before
In the AQL, it is important to understand the table. AQL inspection has two tables that have their own parameters. The tables are:
Single Sampling for normal inspection (Table A)
Acceptable Quality Level (Table B)
Single Sampling for normal inspection shows the lot size and sample size code letters (Given Below – Table A).
Acceptable Quality Level shows the tolerance of the quality (Given Below – Table B).
These two tables are the ones that you will use in the process of AQL and quality acceptance.
4. What is AQL level setting?
There is a term used in the Acceptable Quality Limit procedure and that is the AQL setting. AQL setting is basically the level of strictness and expectations when a product is under testing.
If we talk about normal inspection, the AQL level setting ranges from 0 to 6.5. Keep in mind that the larger the number of AQL, the testing is more lenient.
If we talk about general inspection, the level is considered to be 2.5. If it is 0, then it is considered a critical defect. If it is 2.5, then it is a major defect. And if it is 4, then it is considered as a minor defect.
The thing is AQL setting is considered according to the product and the sales you are getting. If the majority of the customers are accepting a product with a minor defect, then you can move the setting from 4.
There is no pinpoint rule that settings should be considered as follows, the settings mentioned in this blog are general and are used by most businesses.
5. The common approach to AQL
Let’s talk about the approach that is taken by many inspection agencies in order to perform the quality acceptance procedure in the AQL method.
Most of the QC agencies use ANSI ZI.4-2013 single normal sampling chart as a standard. There are many possible scenarios that are based on the table.
The first step that you need to take is to define the general inspection level. The most common type of general inspection level is GII, it covers almost all parameters and is somewhat inexpensive compared to the other two.
Once you have selected the inspection level, you need to talk about the numbers. Now you have to select the number of samples you are sending for inspection.
After that, by cross-checking from the table columns and rows, you will get a letter. That letter is called code for sample.
After getting the code, you will compare it with the other table (AQL table). That table will show you how many samples you need to pull out. Then you will choose the acceptable quality level for critical, minor, and major defects.
6. Case study of AQL inspection
To make you understand the AQL and its table, let’s talk about a case study. Hopefully, after reading this, you will be able to understand how the AQL step process is done. So that it can meet the quality that end users are expecting.
Let’s take the example of socks. Suppose you have placed an order of 20,000 socks and have taken 7000 of them for the AQL testing. Now, we can say that the lot size that you are sending is 7000.
The second step that you need to do is select the inspection level. Most of the time, business owners select general inspection level 2, because it is the feasible solution. Let’s say that you have selected GII as the inspection level.
From the table A, you can see that your lot size is lying between 3201-10,000 and the general inspection level you have chosen is GII. This gives you a code letter “L”.
Now move to the second table B. Locate the letter L from the second table. It will give you the number of samples that you need to pull from the 7000 lot. In this case, it is 200. Take 200 samples from 7000 and perform testing.
The rules of testing are that you need to set the AQL setting. Most of the time, the setting is 0 for critical defects, 2.5 for major defects, and 4 for minor defects.
Compare the samples you have chosen with the values given above (0, 2.5, 4). See how many samples are lying under these columns. From the table, we can see that:
Major defect acceptable standard is 10 pieces.
Major defect acceptable standard is 11 pieces.
Minor defect acceptable standard is 14 pieces.
Minor defect acceptable standard is 15 pieces.
And that is how you use both of the tables to perform the AQL quality acceptance procedure.
How EJET helps our customers with our AQL inspection?
For EJET’s client, we will also provide professional quality testing related to your goods. We finalize the quality control process with international recognized AQL table. We select end products for sampling.
In most cases, we set 0 for critical defects, 2.5 for major defects, and 4 for minor defects. It means that if the product quantity range is 501-1200, the major defects cannot more than 5, and the minor defects should less than 7.
We will also help you check product quantity, size and weight of cartons, product weight, barcode, marking and label, workmanship. What’s more, carton drop test, on-site test will be also done from our warehouses.
Chapter 3: 3 Main Things Need to be Done before Setting Your Own AQL Limit
In this chapter, we are going to talk about how you can set your own inspection limit or also known as the AQL limit. With the factors that are given below, you can select the AQL limit very easily.
1. Do the proper market research
The first that matters, when you are setting the AQL limit, is the market you are planning to target. See, the thing is we can say that the AQL limit depends on the market, because you will set the limit according to the customer.
Let’s take an example, suppose you are selling jackets in the UK market. Now, we all know that the UK is a cold place and jackets are essential for every person. The customers will surely buy the jacket from sellers like you.
Now, the thing is if you are selling jackets at an increasing rate, then it means that your brand or shop has a demand. Basically, by doing the market research, you will be able to have an idea about what is in demand in different markets.
The products that are in demand will be bought by the customers. Demand increases the urge and customers will leave minor details like a button missing or an improper logo.
If you see that your products are selling despite having minor faults, you can change the AQL limit from 4 to a higher number.
Using this as an example, what we are trying to say is AQL limit depends on the market you are selling. If the product you are targeting runs perfectly in that country, then you can set your own AQL limit.
2. Choose the right product category
The second thing to remember when setting the AQL limit is the product category. See, product categories like medicine, flame-able items cannot afford a high defective rate. Because it can lead towards harming the customers.
They also have a low number in the AQL limit. There is another disadvantage to that. It becomes very expensive to send these kinds of items to testing.
For the reason that they belong to category III of general inspection and sometimes in the category of special inspection.
Let’s take an example, suppose you are selling medical equipment in the US market. Now, the US market is pretty sensitive when talking about medical equipment.
If you are the seller, the customs officer will ask for complete inspection details. So you have to adopt category III of general inspection. Each product will be tested and you cannot afford to increase the AQL limit because of the sensitivity of this category.
So, to conclude this, we recommend you select a niche that is not that sensitive. So that you can set the AQL limit that will not affect the customer in any possible way.
3. Consider what your customers prefer
The last point to remember in the AQL limit is knowing what your customers are preferring. If a seller or a manufacturer knows what their customers are preferring, they can set the AQL limit according to that.
Customer preference will enable them to leave the details that customers are not paying attention to.
For example, let’s say that you are doing the business of jackets in the US. Now the customers love the fur of the quality as well as the zipper of the jacket.
What you can do is focus on these two factors of jackets and leave the details such as buttons, logo design, etc.
This way you will tell the QC agency to leave such details and focus on what customers are looking for in the jacket. This will help you in setting your own AQL limit.
Chapter 4: How to Apply the Knowledge of Quality Acceptance?
Applying the concept of AQL can become difficult for new businesses because they don’t have an idea about what they are looking for. In this chapter, we will explain to you how to follow each step so that you can get the work done easily.
1. Checking the size of the lot
When we say the word lot, we mean how much quantity you are getting from the supplier. That is because the next step of AQL requires you to select the right quantity.
Let’s say that you are getting 5000 items of frisbee from the supplier. Now, the thing is the sample size depends on the quantity you are getting from the supplier.
According to the table A and B, you get the code sample from the lot. So, choosing the right lot size is essential.
Let’s say that the lot you are choosing is the one you are getting from the supplier. So, if the supplier is sending you 5000 items, that means the lot size is 5000 items.
2. What to look for when choosing the sample size?
The second factor in the AQL inspection method is choosing the sample size. Well, this one depends on the lot size. Taking the example 5000 as the lot size, once you have selected the inspection level, it will give you a code.
From the table B, you can match the code and it will give you the sample size. In the case of 5000 items and GIII inspection level, we get the sample size as 315. That means from the 5000 quantity, the test will be performed on 315 items.
You will pick 315 items from the whole lot and will send them to the QC agency. They will perform the test and will notify you about the results.
This feature helps in saving money while making sure that maximum products go under the same testing procedure.
3. What kind of general inspections to choose?
In the AQL table, you will get around the general inspection table. There are basically three types of general inspection and those are defined as GI, GII, and GIII.
GI is the inspection level that is cheap. It is for the businesses who are new to the market. GI is also feasible for products that do not require special or strict inspection. Most of the time GI is done using visual testing or in house testing.
GII is the second type of general inspection that is feasible for businesses that have a name in the market. GII is very common in the AQL testing procedure because it fulfills complete parameters of testing.
GII is more expensive than GI, for the reason that different types of testing are done for making sure that the product complies with the rules and regulations.
GIII is the strictest of them all. It is for the business that cannot afford to increase the AQL limit. If you are in the business of any sensitive product like flammable items, medicines, or electronics, then you have to select GIII testing.
GIII is also expensive because the test performed are in-depth, so that you can get the QC mark for that sensitive item.
Talking about what general inspection to choose, it entirely depends on the budget and the market you are targeting. We have added detail about each type of testing so that you can choose the right one for you.
To conclude, we would like to say that choose the inspection carefully. Because if not, it can lead towards customers officers seizing your items. Plus, not making the right decision can become a life-death situation for your customers.
4. Checking maximum and minimum defects in a sample
Once you have all the information like lot size, sample size, and have selected the inspection type, you can now check the maximum and minimum defects in the samples.
These values are visible in table B and from there you can check which products are accepted and which ones are rejected.
There are multiple benefits of AQL, but those benefits depend on the product type and the market you are targeting. However, some of the benefits are common to AQL.
The first advantage is AQL step process in quality acceptance inspection is less time taking, for the reason that QC agencies do not have to check each and every product.
The second is AQL gives a clear and clean result that helps in making the right decision about whether to sell the product or not. And, lastly, AQL is a less expensive method than other quality acceptance inspection methods.
2. What is the main goal of AQL?
The main goal of AQL is to ensure the maximum number of critical defects, major defects, and minor defects. You can know about what’s the limit of defective products you can have in such an order, and try to control the number as few as possible.
These values give a deep idea about whether you should launch the product in the market or not.
3. How AQL is implemented in sample processing?
At first, a lot size is selected in the AQL sample process. When that is selected, the user has to select the level of inspection (usually general level 2 is selected). This gives you a code in the sampling process.
When you have that, you look for the code in table 2. That code gives the sample size. Then, tests are performed on that sample size, and defects are taken out.
4. What is the difference between QC and QA?
Both of the terms are somewhat the same. However, there is a minor difference between the two. For instance, QC is a process where the quality of the output or final product is checked.
QA is the process where steps are taken to ensure the management of the quality when the product is in the development phase.
Quality assurance, as well as checking, has become an important step in the business of e-commerce. That is because more and more people are entering this business. As a result, If you don’t have a valid certification, customs can seal your items.
It has become important for every person to hire a QC agency so that they can test the product and give the certification.
To get the certification from QC, inspection is required. As AQL is the cheapest yet most effective inspection method, it is preferred by a lot of people because of its multiple advantages.
We have compiled a guide that contains all details about AQL and how it is linked with quality acceptance. You can also understand it easier with the test case scenario we gave in the blog.
If you want to learn more about AQL and the steps of EJET’s QC process, you can contact us via email or can send us a message.