In the link of mass production, in the face of harsh customers, especially aviation and automobile, medical industry requirements before, even under the requirements of 100% full inspection, completely rely on the operator to maintain a clear brain and have skilled skill level, this is an incredible thing. So there are always parts that can't be controlled in place, or even installed on the assembly properly. This can lead to several things. First, the consumption of parts in the production process. Second, the part enters the assembly or assembly link, causing the abnormality of the component or the whole part. In the third and worst case, the component is ignored and reaches the customer. Once the finished product is in the hands of consumers, these components can quickly break down, causing greater losses and customer complaints.