It is easy to be confused by the seemingly endless stream of acronyms and abbreviations that get thrown around when discussing inspections. One of our goals with this blog is to decode some of that language for you (as we have done with DUPRO and with MOQ) as you journey towards bringing a product to market. In this entry, we want to discuss “AQL levels”—what they are, why they are important, and when and how they change.
AQL levels are “Acceptable Quality Limits” and they are defined as “the quality level that is the worst tolerable”. The most important thing to understand is that AQL levels are an industry standard tool, one that can be used to ensure that you and the factory manufacturing your products are on the same page as to what the acceptable bounds are to the quality of your product.
The boundaries are determined by first pairing the lot or batch size (the total number of products you have ordered) with an inspection level. There are a total of 7 inspection levels: Special Inspection Levels 1-4 (S-1, S-2, S-3, and S-4) and General Inspection Levels I-III (GI, GII, and GIII). For the purposes of this post, we will focus on General Inspection Levels. Special Inspection Levels are utilized in situations where only a very small amount of products can be checked—and we will have a separate posting about Special Inspection Levels. The rule of thumb for the General Inspection Levels is that in most scenarios, you will use GII. If you have a long history and a high degree of trust with your manufacturer, you might move down to GI (which is a smaller sample size). If you have a new manufacturer, or there have been recent concerns or failures, you may move up to GIII (a larger sample size).
Once you have determined your Inspection Level, you use that information and your lot or batch size with the Sample Size Code Letters table to determine your Code Letter. For example, if you are using GII, and you have a lot or batch size of 3000 items, your Code Letter will be K. Next, you can choose your AQL levels. The most common AQL levels for most consumer products are 2.5% for major defects, 4.0% for minor defects, and 0 for critical defects. These numbers, however, can change depending on the product and the market—for example: if a product you are producing is a high end piece of jewelry or electronics, or if it will be sold at a very high price in an upscale market, you may want to consider tighter AQL levels while an item with less risk may have looser AQLs. This is a discussion that needs to be had with you and your manufacturer (and as always, we are here to help!). Once the AQL has been determined, you can use the Master Table to determine your sample size (in this example, 125) and the amount of each class of defect that is acceptable within your sample (in our case a maximum of 7 major defects, 10 minor defects, and 0 critical defects).
AQL levels are an important tool that you can use to ensure the quality of your products, and once you understand how the tables work, they are really rather simple! Feel free to use our charts to determine your AQL levels, and remember that we are always here if you have any questions.