If you’re wondering what AQL is all about, you will find all information right here.
From the basic definition, importance, standards to other vital terms relating to AQL.
Keep reading to learn more.
- What does AQL Stand for?
- What is the Meaning of AQL?
- What is the Significance of AQL in International Shipping?
- What is the Importance of Getting an AQL inspection?
- How Many Types of AQL are there?
- What do the Three Categories of Critical, Major, and Minor Defects mean in AQL?
- How is AQL Calculated?
- What is the Standard AQL?
- What does AQL 2.5 Mean?
- What does AQL 4.0 Mean?
- What does AQL 1.5 Medical-grade Mean?
- What Does an AQL 0.65 Mean?
- What is PPM, and How does it Relate to AQL?
- When should you Use AQL Sampling in International Shipping?
- How do you Read the Sampling Table in AQL?
- What is the C=0 Sampling Plan?
- What is Normal Inspection?
- Is AQL Better than a Normal Inspection?
- What is AQL in Textile?
- What is LTPD?
- How does AQL compare to LTPD?
- How do you Determine Sample Size in AQL Sampling?
- What are the Alternatives of AQL for Quality Inspection?
- How do you Determine an AQL Sampling Plan?
- What is the AQL Level?
- How do you Choose an AQL Limit for your Products?
- Can AQL Guarantee Zero Defective Goods?
- Can you Save a Defective Batch of Goods after AQL Sampling?
- Is it Possible to do your Sampling Plan for Goods?
- How do you Determine the Sample Size in AQL?
- Can you have the Same AQL Limit for All Products going Through the Same Distribution Channel?
- Is AQL Sampling Standard only for Finished Products?
- What is RQL?
- How is RQL Calculated?
- What is the Relationship between AQL and RQL?
- What Happens when the Number of Defective Products is above the AQL?
- As a Buyer, Should I Chargeback the Value of the Defective Products to the Manufacturer?
- What is Special Inspection Level in AQL?
- What is the Difference Between the Special Inspection Level and the General Inspection Level?
- What is an Operating Characteristic Curve (OC)?
- Why would you choose AQL Sampling over 100% Inspection?
What does AQL Stand for?
According to ISO 2859-1, AQL represents the Accepted Quality Level.
What is the Meaning of AQL?
Accepted Quality Level (AQL) is the maximum quantity of defects accepted in a product.
During sampling of products for quality check, AQL is used as a baseline to determine whether a given shipment is accepted or rejected.
It is an internationally recognized system used to ascertain the quality in % of the sample compared to the total shipment.
What is the Significance of AQL in International Shipping?
Quality control can be nerve-wracking when it comes to international shipping, but is it crucial.
You want the best products from your seller free of defects.
You are also short of the budget and workforce to do an individual assessment on each product scheduled for shipping.
In this case, AQL sampling comes in handy to ensure you get value for your money.
By doing a quality check at the production point, you ascertain your products’ quality before they are shipped.
AQL sampling offers time convenience because you don’t want to inspect the whole lot being shipped.
You’d take a lot of time and incur huge expenses doing a 100% quality check.
Unlike the arbitrary sampling method where you choose, say 10% of the total order.
AQL sampling provides a unique random process that ensures the result is accurate and unbiased.
What is the Importance of Getting an AQL inspection?
Inspection is critical in ensuring your supplier is regularly providing quality goods that match your money.
AQL is preferred in most cases since it allows for a fair representation of what the whole order contains.
Getting an AQL inspection has the following benefits;
- You want to check the quality of your order, but at the same time, you want your order to be shipped as quickly as possible.
Having a sample taken for inspection saves you time and assure you of quality.
- 100% inspection of the order is expensive and requires a larger workforce.
Settling for AQL sampling will save you on costs without compromising the quality check results.
- AQL sampling offers specific results that are subjective to the desired quality checks.
It is a direct method and is based on acceptance and rejection.
If the defects in the sample surpass a set limit, you automatically reject the order.
How Many Types of AQL are there?
Two types of AQL are further subdivided into different levels.
General Inspection Level
The general inspection level is the widely used AQL when the quality check has no impact on the products, and time and resources are not a factor.
GI Inspection Level
The GI inspection level is the most economical and time-saving.
It picks on the smallest sample size to analyze the quality of the entire supply.
GI is useful when dealing with return suppliers who have a history of providing you with quality products.
It is also useful when you are not ready to meet the costs and lack the time needed to carry out thorough inspections.
GI level employs the use of set standards during quality checks to give conclusions.
As an importer, you can set your quality level for minor defects at 4 and 0 for critical defects.
This means that if defective products in the sample size exceed 4%, then you reject the products.
The higher you place your acceptable quality level, the higher you tolerate defective products in your shipment.
GII Inspection Level
GII is also referred to as the normal sample size.
Most importers adopt it as it includes major products in the sample at a lower cost.
It is useful when dealing with a client for the first time or sourcing new orders from the same supplier.
With GII, you are assessing the quality of the first batch of orders.
If you are using the same quality level, you should raise your acceptable level since there is an increase in sample size.
GIII Inspection Level
From the trend, GII takes the longest time as it includes the biggest sample size.
However, GII inspection is critical has it gives the best result in terms of a representative quality.
GIII is useful in cases where your supplier has a lousy reputation for continuously supplying defective products.
Also, when dealing with a supplier for the first time or when the product is of higher value and directly affects people’s health.
Nevertheless, GIII takes the longest time.
It is only appropriate if you are willing to spend more time and can afford the cost of hiring a workforce for the sampling.
Special Inspection Level
The special inspection level is used when you need to verify quality, but the time and resources available are limited.
It is grouped into four categories, each with a set AQL number for acceptance and rejection.
What do the Three Categories of Critical, Major, and Minor Defects mean in AQL?
These are categories of defects o AQL sampling.
Minor defects refer to products that have the least deviation from the intended quality.
Such products are accepted because, despite their slight defection, consumers won’t mind using or purchasing them.
An example is an ordered radio that lacks one or two screws but is still functioning.
The minor defects are assigned a large AQL (4.0), which means their rejection rates are low.
It refers to products that, during the time of production, fail to meet the quality standards.
The products have a higher probability of being rejected in the market.
An example of such a product can be a television that operates but lacks the remote.
The products have a slightly higher probability of being rejected (2.5).
They are usually in specific industries where a single error can lead to a lot of damage.
Therefore, critical defects are unacceptable.
When a quality inspection is done, and a single defect is discovered, the whole lot is rejected.
An example is a mobile phone that continuously heats up while in the pocket.
This affects the health and is rate 0.
How is AQL Calculated?
The use of the AQL continues evolving since the 1920s when it was first designed.
The goal is to have products that have 95% chances of being accepted by the customer.
There is no default AQL limit prescribed for use.
You can choose a critical limit (0) if the order should have no defect and minor (2.5) for consumables.
Major (4) is recommendable in cases where your consumers are not strict on quality.
You can use the online AQL calculator tool to give you the sample size.
Input the lot size, then select the inspection type, either general or specific.
The next step is choosing the inspection level and, finally, the AQL.
The tool is automated and will give you the accept point and the reject point.
What is the Standard AQL?
There is no standard AQL that is used for assessing quality in all products.
It depends on an individual customer’s needs and that of the supplier.
Setting the AQL lower can lead to rejection by the supplier while setting it higher can lead to having more defective goods.
You should set the AQL limit after analyzing the market you operate and the type of goods you want to order.
What does AQL 2.5 Mean?
An Accepted Quality Level of 2.5 means that out of the sample picked for inspection, the buyer is willing to accept a defective rate of 2.5% of the total shipment.
If the number of defective products is above 2.5% of the order, then the order is rejected.
Conversely, if the total number of defective products is less than 2.5%, the order is accepted.
What does AQL 4.0 Mean?
AQL 4.0 provides the largest freedom of accepted defects.
It refers to the total amount of defective products the customer can take.
AQL 4 is used for minor defects and in cases where users of the products will still go ahead and purchase the product despite the defect.
What does AQL 1.5 Medical-grade Mean?
AQL 1.5 means that if the defective products are above 1.5% in the total order, the order is rejected.
On the other hand, AQL 1.5 is used to inform the suppliers that the order will only be accepted if the total defects are less than 1.5% of the whole order.
What Does an AQL 0.65 Mean?
After sampling and conducting a quality check, the sample’s total defects are converted to give a probability of defective products in the whole lot.
AQL 0.65 means that the customer will only accept the order if the number of defective products in the whole lot is less than 0.65%.
What is PPM, and How does it Relate to AQL?
Ppm refers to parts per million.
It is frequently used in the manufacturing industry to evaluate defective products per million of production.
Suppose you placed a shipment of 1000 goods and got 25 defective products.
The defective rate will be 25/1000= 0.025.
In such a case, the ppm would be 0.025 X 1,000,000 = 25,000ppm.
Meaning that out of a million manufactured products, twenty-five thousand are defective.
Ppm’s implication is to show you the probability of the actual defective products you can get from a single manufacturer if you increase or reduce your order.
When should you Use AQL Sampling in International Shipping?
When it comes to international shipping, you are mostly dealing with suppliers outside your reach.
Most of the time, you want to ensure that only quality products aboard the shipping vessels for delivery.
Therefore, you need to have a proper technique for verifying quality to reduce defective goods instances.
Other quality check techniques can involve a 100% check on the order.
But this is expensive and time-consuming hence the need to choose the AQL sampling method.
The AQL sampling technique is effective if;
- Your supplier’s manufacturing method is automated, and the production is done in batches.
AQL is therefore done to ascertain that each pack meets the required quality threshold.
- Suppose your supplier’s reputation shows that they are not predictable in supplying 100% quality goods.
You can use an AQL that will allow you to verify the quality being shipped and make decisions before the goods are shipped.
- When dealing with large orders and normal quality inspections deem to be time-consuming and expensive.
How do you Read the Sampling Table in AQL?
The AQL sampling table might look confusing for first-time shippers.
But as you continue placing more and more orders, you will understand how to read the AQL table and appreciate it.
There are two sampling AQL tables.
The first table contains the sample size code letters.
Size code letters
It includes the lot sizes, three general inspection levels, and four special inspection levels.
The lot size offers ranges for the number of orders you have placed.
While the general inspection level and the special inspection levels provide the AQL, you will use.
The second table provides the sample size code letters and the sample sizes. It also provides the AQL levels for rejection and acceptance.
Sample size code letters
To read the table and know whether you should accept or reject the order, you start by knowing your order quantity.
- In the first table, select the category in which your order falls. Then select the AQL that provides you minimum accepted defects.
- On the same column as your order quantity, read the letter to your right and below the chosen AQL level.
- After reading the sample size code letter, move to the second table on single sampling plans for normal inspection. Read the letter against the AQL codes, along the same row in the second column; you will find the sample size.
As you move to the next column and below the AQL you chose, read the two numbers, that of the accepted quality level and the rejected quality level.
If the sample size has a large number of defective products, it will be rejected.
What is the C=0 Sampling Plan?
The C=0 sampling plan is used in sensitive goods where not even a single defect is needed.
Under the C=0 plan, products are accepted only if zero defects are observed during the inspection.
If a single defect is observed from the sample, the whole order is rejected.
The purpose of using the C=0 sampling plan is to protect consumers who deal in products that relate to health and welfare.
The C=O plan means that the order must meet 100% quality standards to be accepted.
What is Normal Inspection?
Normal inspection is also referred to as the Level II inspection. It is used when there is no cause for alarm on the quality of the order.
It is the default inspection type and is preferred in more than 90% of inspections.
The normal inspection gives either greater discrimination or lesser discrimination hence ideal.
Is AQL Better than a Normal Inspection?
You already know what AQL is about inspecting a sample of the whole order to determine if it meets the minimum quality standard.
Normal inspection is used only when there is no reason to have defective products in the lot.
Therefore, AQL is more reliable, and the findings give an accurate representation of the whole lot ordered.
What is AQL in Textile?
The term AQL is commonly used in the textile industry to define the maximum percentage of acceptable defects.
AQL shows the quality level of the manufactured textile that meets the consumer’s demand.
It is essential to understand that the minimum percentage differs from one buyer to the other.
There is no static AQL that is accepted by all customers.
There are four classifications of AQL in the textile industry.
- Minor defects usually at 4% (the highest level of accepted defects, but consumers won’t mind purchasing the product).
- Major defects normally at 2.5% (Customers won’t consider the products)
- Critical defects no range (The garment must be 100% original, and any slight defects will lead to rejection by customers)
- Slight defects are rated at 0.65% and are always detected within the manufacturing process.
What is LTPD?
Lot Tolerance Percent Defective (LTPD) is the total quality level usually rejected by the sampling plan.
It shows the frequency in which the total defect quantity will be accepted 10% of the time and rejected 90%.
Essentially, LTPD shows the confidence level within which the results from a sample plan will be rejected or accepted.
How does AQL compare to LTPD?
AQL refers to the maximum defect rate accepted by a customer before allowing the goods to be shipped.
Conversely, LTPD refers to the level of quality that is frequently rejected by the sampling plan.
LTPD is the percent defective per hundred units that the sampling plan will accept 10% and reject 90%.
How do you Determine Sample Size in AQL Sampling?
The sample size refers to the representative number of products included in the quality analysis.
The ANSI ZI.4-2013 provides a standard chart used to determine the sample size.
There is the lot size representing the total quantity of orders you’ve placed in the first chart.
You can choose an inspection level under the general inspection levels in the category where your order falls.
Once you have the letter corresponding to the order quantity and the inspection level, head over to table two, along with the columns, you will see your sample size.
What are the Alternatives of AQL for Quality Inspection?
Depending on the industry and shipping country, your products must conform to specific standards measured using certain quality inspection techniques.
AQL is not sufficient and sometimes leaves critical details that constitute the quality of the product.
Other alternatives to the AQL sampling technique are;
- Confidence/reliability calculations- provides a simpler method of calculations using tables and electronic spreadsheets.
- Attribute data
- Squeglia’s C=0
- OC curves
- ANSI Z1.4
How do you Determine an AQL Sampling Plan?
An AQL sampling plan is simply a detailed sampling execution program.
The sample plan outlines the purpose of the plan, who will carry out the sample, the time, and which material will be used.
AQL provides a guide on how the sampling goals will be achieved and how the collected data will correctly represent the whole order.
The steps involved in the AQL sampling plan include:
- Identifying the features to be evaluated, the range of values to be used, and the desired results to be achieved.
- You then decide a scheme of work on the timing and the number of samples to be taken.
- Choose the sample size.
- Formulate how data gathered will be stored.
- Assign the sampling team their roles and responsibilities.
An AQL sampling plan is not complete until it is agreed upon and accepted by the whole sampling execution team.
What is the AQL Level?
When dealing with international business, you must set quality standards on the goods that your supplier ships.
AQL level provides you with a means to verify the quality of the order you placed before they are loaded for shipping.
The AQL level is the minimum quality that the order must meet before it is accepted.
It provides the maximum number of defective products that can be accepted.
How do you Choose an AQL Limit for your Products?
There are different AQL limits allowed when importing.
There is no restriction on what you can choose.
All you have to do is decide the maximum number of defective products you can allow in your order.
Before choosing the maximum AQL limit for your order, you should first consider,
Some markets are competitive and require high-end products.
Such markets require strict quality monitoring, and you can choose to have lower AQL limits.
If you are operating a boutique, you can choose to have strict AQL like 1, 1.5, 0.2.
On the other hand, if your market is open low end, markets where your customers consider price before quality, you can choose looser AQL limits like 2.5 and 4.
Suppose you are operating in critical industries that deal with human welfare, such as pharmaceuticals and the transportation industry.
In that case, your AQL level must be high, and sometimes no single defect is allowed.
Such industries can have AQL levels of less than 1%.
Can AQL Guarantee Zero Defective Goods?
All manufacturing processes are marred with flaws.
No supplier can guarantee you 100% quality products.
AQL sampling method is effective in saving time and costs in inspections.
Sometimes the probability that the defective good in the order is picked is not guaranteed.
Besides, AQL only checks the quality standard against a predetermined checklist.
Therefore, some defects go unnoticed.
There is no guarantee that AQL will offer zero defective goods.
You should use more than one quality check technique to ensure that your order meets the desired quality level.
Can you Save a Defective Batch of Goods after AQL Sampling?
The results of an AQL sampling leave a lot to discuss how you handle defective products.
It is paramount to priorly agree with your supplier in advance on how to handle faulty goods.
During sampling, the lower your AQL limit, the higher the chances of finding more defective products.
In such a case, if the order does not meet your AQL limits, you reject the whole order.
However, if the order meets your AQL limit but you still find some defective products, the decision is yours.
It will depend on your agreement with the supplier.
You can choose to keep the defective products, have your supplier change them, or chargeback the supplier’s defective products’ cost.
Is it Possible to do your Sampling Plan for Goods?
Depending on your needs, you can choose to do your sampling plan.
However, choosing your sampling plan puts you at the risk of allowing more defective products to pass the test of quality.
It would help if you stuck to the prescribed sampling standard because it offers an accepted outline of choosing a suitable sample size.
The results are conclusive enough to make informed decisions.
How do you Determine the Sample Size in AQL?
The sample size is the number of representative units that are used to carry out the tests.
In AQL, the sample size should be as representative as possible.
You can get the sample size directly from the standard AQL table.
- Decide the AQL you will use and its category, whether it falls under the general or special level.
- Locate your order quantity in the row containing lot size.
- Along the same column with your order quantity, move towards the right until you are directly below the AQL you chose and record the letter.
- With the letter, move to table two and in the first column, move to the second column on the same row you will find the sample size to use in the test.
Can you have the Same AQL Limit for All Products going Through the Same Distribution Channel?
Yes, but is it is not advisable.
When shipping from overseas, you need to be strict when it comes to quality control.
You can opt for the normal AQL limits such as 0, 1.5, and 0.25 for products going through the same distribution channel.
This is only if you’re sure that nothing will change in the manufacturing process or components used in production.
Otherwise, you ought to be stricter with your acceptable defect levels.
In this case, choose limits of 0, 1, 1.5, or 2.5 to represent critical, major, and minor defects, respectively.
Note that before deciding on the AQL limit to use in your product, there are several factors you should consider.
First, your target market will greatly dictate the AQL limit you choose.
In the competitive market, you should decide on a strict AQL limit.
Secondly, the type of product you deal in will greatly affect the AQL limit you use.
Suppose you are dealing in general consumables, and your customers will purchase your products regardless of quality.
You can choose the same AQL limit while operating through the same distribution channel.
Is AQL Sampling Standard only for Finished Products?
AQL sampling can be done on any product.
This is as long as the sample size can be classified as ‘ok’ or ‘defective.’
Note that the AQL sampling standard is used for checking lots of goods.
It can also be used to verify the accuracy of inventory or invoices.
What is RQL?
Rejectable Quality Level (RQL) refers to the highest number of defective products in a given order that the customer is willing to accept.
The RQL denotes the maximum risk a consumer is willing to take by accepting a definite percentage of defective goods.
How is RQL Calculated?
RQL is the defective rate that customers wish to reject at a higher proportion of times (β).
Suppose your consumer risk alpha is 0.10 and the RQL is 8%.
This means that you accept orders that have 8% defective goods 10% of the time.
What is the Relationship between AQL and RQL?
AQL and RQL
AQL determines what the sampling plan will accept, while RQL shows what the sampling plan will reject.
Both AQL and RQL are important in shipping.
The supplier and the consumer should agree on the highest defective rate that is acceptable.
They should also agree on the total number of defective products that the customer will accept.
What Happens when the Number of Defective Products is above the AQL?
After conducting the inspection and finding out that the number of defective products is higher than the AQL you have set, you don’t simply reject the order.
The majority of orders placed are not exact as ordered.
First, you should verify the quantity of orders placed and look at the probability of having other orders replace the defective ones.
Depending on your agreement with the supplier, you can transport the whole order to the factory for replacement.
Alternatively, you can have only the specific defective orders replaced.
As a Buyer, Should I Chargeback the Value of the Defective Products to the Manufacturer?
The purpose of conducting an AQL is to determine your products’ quality level before they are imported.
If the products fail to meet the AQL test, they are rejected, and your supplier is responsible for replacing them.
However, when the supplier provides other products subjected to a similar AQL check, they must pay for the subsequent AQL test.
What is Special Inspection Level in AQL?
There are two types of inspection levels in AQL sampling.
The majority of your shipment will use the general inspection level to determine the AQL limit.
The special inspection is effective in situations where;
- The result gotten from the test is the same across all the products.
- The time to carry out the tests is long, and you do not see value in keeping your goods waiting.
- The cost of carrying out the tests is high, and you are not willing to spend on it.
In such cases, you should work closely with your inspection company to get advice before deciding to continue with importation if they see the tests important.
What is the Difference Between the Special Inspection Level and the General Inspection Level?
Along the column, as you move right in the AQL table, the sample size reduces.
This means that the general inspection level offers more samples to be tested than the special inspection level.
Special inspection level is used when the test is conducted in the order is equal in the lot, while the general inspection level is used in different tests.
The time and cost of carrying out a special inspection level are less than needed to carry out the general inspection level.
Before settling to use general or special inspection level, first, consult and ensure the choice you make favors the quality you want in your products.
What is an Operating Characteristic Curve (OC)?
The OC curve is a chart that plots the relationship between the probability of acceptance and the percentage of defective goods.
This curve shows that when the percentage of defective items is zero, there is a 100% probability that the order will be accepted.
As the proportion of defective products increases, the probability of accepting the order reduces to zero.
The OC curve clarifies how the increase in the number of defective products will affect customers’ rejection or acceptance rate.
Why would you choose AQL Sampling over 100% Inspection?
The purpose of an inspection is to check whether what you agreed with your supplier is the same thing they plan on shipping to you.
100% inspection means that if you place an order of 1000 products, each product must be inspected to determine if it has the agreed quality.
AQL sampling, on the other hand, offers a simple assumption basis by which you pick a small percentage of the whole order, analyze it and assume that the whole lot is the same.
Before choosing a supplier, you should research and ensure they meet your quality standards.
This way, AQL will save you time and money as compared to carrying out 100% sampling.
Now, in case we did not answer your question, BanSar team is still here to help you understand every aspect of AQL.
Contact us now for free consultations and inquiries.