The current test methods mainly include the following five types:
1. Manual vision test
Manual vision testing is to confirm component placement on the PCB through human vision and comparison. This technology is one of the most widely used online testing methods. But with the increase in production and zoom out the circuit boards and components, this method is becoming less and less applicable. Low pre-cost and no test fixtures are its main advantages; at the same time, high long-term costs, discontinuous defect discovery, data collection difficulties, no electrical testing, and visual limitations are also major drawbacks of this approach.
2. AOI (Automated Optical Inspection)
This test method, also known as automatic vision test, is usually used before and after reflow. It is a relatively new method of confirming manufacturing defects. It is better to check the polarity of components and the existence of components. It is a non-electrical, no fixtures online technology. Its main advantages are easy to follow diagnostics, easy development of the program and no fixtures; the main disadvantages are poor short circuit identification and not electrical testing.
3.Functional Test
Functional test is the earliest automatic test principle. It is a basic test method for a specific PCB or a specific unit and can be completed with various test equipments. Functional tests mainly include Final Product Test and Hot Mock-up.
4.Flying-Probe Tester
The flying probe tester, also called a probe tester, is also a commonly used test method. Due to advances in mechanical precision, speed, and reliability, it has been generally welcomed in the past few years. In addition, flying probe testing is now the best choice for prototype manufacturing and low-volume manufacturing. The main advantage of the flying probe tester is that it is the fastest time to market tool, automatic test generation, no fixture cost, good diagnostics and easy programming.
5.MDA (Manufacturing Defect Analyzer)
MDA is a good tool for diagnosing manufacturing defects only in high-production/low-mix environments. The main advantages of this test method are lower cost in the early stage, high output, easy follow-up diagnosis and rapid complete short circuit and open circuit test, etc. The main disadvantage is that the functional test cannot be performed, there is usually no test coverage instruction, fixtures must be used, and the test cost is high.