PCBA is the abbreviation of Printed Circuit Board Assembly, is the PCB empty board after the SMT process on the pieces, or after the DIP plug-in the entire process, referred to as PCBA is an important electronic component, is the electronic components of the support body, is the electronic components of the line connection provider. Because it is made using electronic printing technology, it is called a “printed” circuit board. Before the emergence of printed circuit boards, the interconnection between electronic components is dependent on the direct connection of wires to form a complete line.
PCBA production process
The production process of PCBA includes the following main steps: designing a suitable circuit board through circuit design, purchasing according to the list of components on the circuit board to ensure that the quality of components is reliable, and then through the SMT mounting technology to small electronic components mounted to the circuit board in the specified location, for some components that are not suitable for SMT mounting, the need for DIP plug-in processing manually complete the completion of the component mounting and plug-ins, the need to weld, weld is completed, and then curing treatment to enhance the mechanical strength of the welded joints and electrical properties. After the welding is completed, the curing process is carried out to enhance the mechanical strength and electrical properties of the welding points. After the completion of the above steps, the circuit board cleaning process, remove flux, oil, and other impurities, and carefully check to ensure that there is no false soldering, leakage of welding and other defects, etc., after the test and inspection of qualified, packaging and shipping to ensure that the product meets the relevant standards and quality requirements.
PCBA (Printed Circuit Board Assembly) test types
In-Circuit Testing (ICT): Test probes contact test points on the PCB to detect circuit openings, shorts, and part failures test method.
Functional Test (FCT): The FCT test is usually similar to the ICT test, which is mainly conducted from the IO ports of the board, and comprehensively tests the functional modules of the board to ensure its quality.
Aging Test: Tests the stability and reliability of products in specific environments, simulating various factors under real-life use conditions, usually including high temperature and high humidity tests, vibration tests, etc.
Automated Optical Inspection (AOI): AOI is often used in combination with other test methods, such as AOI and ICT or AOI and FCT, using a camera to take a picture of the PCB and compare it with the schematic to detect whether there is a fault on the board.
Voltage Withstand Test: Evaluates the voltage withstand capability of a circuit board by gradually increasing the voltage to a certain value and holding it for a certain period to test the board's voltage withstand capability.
Insulation Test: Tests the board's insulation properties to ensure that there is no current leakage under normal operating conditions.
Salt Spray Test: Expose the board to salt spray to simulate marine or high humidity environments, and test and evaluate the board's corrosion resistance.
Impedance Test: An ohmmeter is used to measure the impedance value of the board to check the normal operation of the board wiring.
Vibration Test: Vibration test in three axes to detect the vibration resistance, and test and evaluate the performance of the circuit board under the influence of vibration.
High Temperature/High Humidity Test: Tests the board's performance under extreme temperature and humidity conditions.
Solder Strength Thrust Test: This test determines whether components are easily desoldered by using a thrust meter toevaluate the solder strength of components on the board.
Together, these test methods ensure the quality and reliability of PCBAs and help manufacturers identify and resolve problems promptly during the production process.、
PCBA function test commonly used instruments
Including ICT tester, FCT tester, and aging tester.
ICT tester (In-Circuit Tester) is an automatic online tester, through the test probe contacts PCB on the test point to detect the electrical performance of the PCBA and connectivity, detection of circuit board lines open circuits, short circuits, component damage, and other issues.
FCT Tester (Functional Circuit Tester), through the burn-in IC program to detect problems in hardware and software, can comprehensively test the functional modules of the circuit board to ensure product quality.
Aging Testers simulate various factors under real-life usage conditions to test products' stability and reliability. By placing the product under specific temperature, humidity, and other conditions for a sustained period of time, the data is recorded to assess the product's performance.
Other Related Test Methods
In addition to the above instruments, PCBA testing can also use automatic optical inspection (AOI) and flying probe testers, AOI is suitable for detecting problems such as low tin, low material, false solder, etc. Flying probe testing is suitable for prototyping. Flying probe testing is used for prototyping and low-volume manufacturing.
PCBA Functional Test Flow and Considerations
The principle of the PCBA function test is to conduct a comprehensive inspection of the circuit board and the electronic components on it by simulating the actual use environment to ensure that its function meets the design requirements.
Before powering up, carry out a pre-power-up inspection to check the appearance of the PCBA to ensure that there are no short circuits, open circuits, wrong parts, leakage, or other problems.
At the same time, check the welding quality, such as whether the solder joints are full and smooth, and whether there is a phenomenon such as false welding, or continuous welding. After confirming that the appearance of the PCBA is not abnormal, carry out a power-on test to check whether the power supply circuit works normally, whether the voltage output is stable, and whether there is overcurrent, overvoltage, and other protection functions. After that, according to the product design requirements, the PCBA functions one by one check to verify that each meets the requirements. In addition to the normal function test, it is also necessary to carry out a boundary condition test on the PCBA to verify its performance under extreme conditions, to ensure that the circuit board and its components work correctly according to the design requirements, and to achieve the expected performance and reliability.
Conclusion
Regardless of the method chosen, PCB testing is a necessary step in the circuit board design and manufacturing process and can save a great deal of unnecessary time and cost before entering final production.
In general, the right combination of the above inspection and test methods can detect all possible defects at a cost that depends on the specific application and complexity of the circuit under test.