PCB manufacturers use a variety of test methods to ensure PCB quality when shipping, which allow PCB manufacturers to test the effectiveness of components and PCBS. Here are some of the proven methods employed by PCB manufacturers.
1. online testing: also known as ICT, this test is mainly used to check the placement of components. Electrical probes are used on assembled printed circuit boards to check for factors such as open and short circuits, capacitance, resistance, etc. Online testing consists of several individual tests of a component. If all these individual tests can be cleared, then the board is considered ideal.
2. functional testing: This is the final step in the manufacture of PCB circuit board manufacturers. Functional tests simulate the actual environment in which the PCB is expected to be executed. Thermal simulation testing is one of the most popular forms of functional testing used to analyze the functionality of a PCB. This test is often used in conjunction with flight probe testing and ICT to ensure that the PCBA is error-free and robust.
3. boundary scan test: PCB circuit board manufacturers perform this test to test the wires on the filled printed circuit board. It is also used to analyze pin states in integrated circuits, as well as to measure and analyze their impact.
4. Flying needle testing: Also known as jig-free online testing (FICT), used to identify accessibility issues. This test is ideal for testing prototypes and medium-sized types. This test is usually performed using a nail bed fixture, which can be easily modified according to the PCBA design. After PCB inspection, PCB testing is the next stage of PCB manufacturing. Once the PCB has been inspected, it is ready for testing. PCB circuit board manufacturers use a variety of test methods to analyze the working condition of components.
5. tin whisker test: tin is a commonly used finishing material for PCB circuit board manufacturers. This material grows into a whisker, which may conduct electricity and affect the operation of the application. Typically, these whiskers are corrected with a conformal coating, or finished with metal instead of tin.
6. optical microscope test: This test method is used by PCB manufacturers to detect defects, faults and some other problems in PCB assembly. Optical microscopy tests are performed using high-power microscopes. Each component is divided into several microscopic parts and tested under a microscope. This technique is often combined with microsectioning to ensure effective performance of the sample.
7. metallographic preparation: This method is also known as cross section or microscopic section analysis. Perform cross-sectional studies of parts, short circuits or breaks, thermal mechanical failures, etc. During the test, the interior of the solder joint was analyzed. The 2D cross-section is removed from the PCB and then placed in epoxy resin. After curing, the component will retreat and be exposed. Abrasives are used for backing up. The exposed components are compared to other non-faulty components and examined using an electron/light microscope.
8. Burn-in test: This test helps PCB assembly services verify the performance of PCBS in real-world environments.
9. PCB contamination testing: Although the manufacturing and assembly of PCBS are carried out in a controlled environment, the opportunity for contamination from various identified and unidentified sources remains high. Flux residue, improper disposal of PCBS, and chemical reactions are several common sources of contamination. During this process, the PCB is immersed in the solution and left for a certain amount of time. The composition of the solvent changes due to the presence of ionic contaminants.
Each of the above mentioned PCB testing process has typical benefits, each test method has its own advantages and disadvantages, and how to choose the method, PCB circuit board manufacturers can only give advice, is according to the customer's own needs to choose the test method.
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