Assembly testing relates to the testing of a printed circuit board at the PCB assembly phase of manufacture, after the board has been populated with all components specified in its associated Bill of Materials (BOM). As such, it is often referred to as in-circuit or electrical testing. This method of testing typically involves (but is in no way limited to!) the use of a manually-configured bed-of-nails fixture. Depending on the type of testing being performed using the fixture, the board may or may not be powered up.
1. Visual test by hand
Manual visual test is by comparing people's vision and to confirm the components on the PCB SMT, this technology is one of the most widely used online test method. But with the increase of output and the narrowing of the board and the component, this method does not apply to more and more. Low cost in advance and without the test fixture is its main advantage; At the same time, the high cost of the long-term, discontinuous defects found, the data collection difficulty, no electrical test and the limitations on the vision is the main drawback of this method.
2. The automatic Optical Inspection (Automated Optical Inspection, AOI)
Also known as automatic visual testing, the testing method usually used before, during, and after reflow, is a new method of confirm manufacturing defect, the check about the existence of the polarity of the components, components effect is better. It is a kind of electric, no jig online technology. Its main advantage is easy to follow diagnosis, easy application development and without fixture; Main drawback is that the short circuit identification is poorer, and not the electrical test.
3. The Functional Test (Functional Test)
Functional testing is the first principle of automatic test, it is specific PCB or a specific unit of the basic testing methods, available to all kinds of test equipment to complete. Functional tests are the Final Product testing (Final Product Test) and the latest entity model (Hot Mock - up) two kinds.
4. The Flying Probe Tester (Flying Probe Tester)
Flying probe tester also known as the probe testing machine, is also a kind of commonly used test smethods. Due to the progress of mechanical precision, speed and reliability, it in the past few years have been widely welcomed. In addition, now for the Prototype (Prototype) needed to manufacture, low production test system is capable of rapid transformation, no fixture requirements, best choice makes flying probe test. Flying probe tester's main advantage is that it is the most rapid Time To Market, Time To Market) tools, automatic generation of test, no jig cost, good diagnosis and easy programming.
5. Manufacturing Defect Analyzer (Manufacturing Defect Analyzer, MDA)
MDA is a used for high volume/low mixing environment only the good tool in the diagnosis of manufacturing defect. The test of the early stage of the main advantage is lower cost, high output, easy to follow the rapid diagnosis and complete a short circuit and open circuit test, etc.; Main drawback is not a functional test of PCBA, there is usually no test coverage instructions, must use the jig, test cost is higher.