1. Manual visual test
Manual vision testing is to confirm the component mounting on PCB through human vision and comparison. This technology is one of the most widely used online testing methods. However, with the increase of output and the reduction of circuit boards and components, this method is becoming more and more unsuitable. Low pre cost and no test fixture are its main advantages; At the same time, high long-term cost, discontinuous defect detection, difficult data collection, no electrical test and visual limitations are also the main disadvantages of this method.
2. Automated optical inspection (AOI)
This test method, also known as automatic visual test, is usually used before and after reflow. It is a relatively new method to confirm manufacturing defects. It has a good effect on the polarity of components and whether components exist. It is a non electrical, fixture free on-line technology. Its main advantages are easy to follow diagnosis, easy program development and no fixture; The main disadvantage is poor short circuit identification and is not an electrical test.
3. Functional test
Functional test is the earliest automatic test principle. It is the basic test method of specific PCB or specific unit, which can be completed by various test equipment. Functional tests mainly include final product test and hot mock up.
4. Flying Probe Tester
Flying needle testing machine, also known as probe testing machine, is also a common testing method. Due to the progress in mechanical accuracy, speed and reliability, it has been widely welcomed in the past few years. In addition, the requirements for the test system with fast conversion and fixture free capability required for prototype manufacturing and low-yield manufacturing make the flying needle test the best choice. The main advantage of the flying needle tester is that it is the fastest time to market tool, automatically generates tests, no fixture cost, good diagnosis and easy programming.
5. Manufacturing defect analyzer (MDA)
MDA is a good tool for diagnosing only manufacturing defects in high-yield / low mixed environments. The main advantages of this test method are low initial cost, high output, easy to follow diagnosis, fast and complete short circuit and open circuit test, etc; The main disadvantage is that the function test cannot be carried out, there is usually no test coverage indication, the fixture must be used, and the test cost is high.
