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The PCBA test is normally placed at the back of the processing process, and the function is to check the integrity of the PCBA product. The test must be carried out in strict accordance with the regulations to improve the accuracy of the test, thereby improving the quality of shipments from the PCBA processing plant. The PCBA test is mainly to test the function, power calibration, life, performance and other data of the product. So what equipment is needed for testing? At present, the main test fixtures used in the PCBA production line are classified as follows:
Under normal circumstances PCBA processing factories can do those tests
1. ICT test
This test is mainly for PCB circuit boards and components, the application range is relatively small, and the equipment is relatively expensive, often only high-end products will be used, its function mainly includes the circuit's on-off, voltage and current values and fluctuation curves, Amplitude, noise, etc.
2. FCT test
After the PCBA production is completed, it is necessary to burn the program of the product into the IC, and then perform a functional simulation test on the finished product. Then this step is the FCT test, which can detect the problems in the hardware and software in time. And feedback to customers for software optimization and hardware problem improvement. This test is a must-have for PCBA processing factories.
Under normal circumstances PCBA processing factories can do those tests
3. Fatigue test
As the name suggests, the fatigue test is to test the durability of the PCBA, to see how long the circuit board can withstand the use of it before it fails. The test is generally the same batch of sampling testing. After high frequency and long time operation, detect the probability and proportion of failure, and use this parameter to determine the number ratio of fatigue.
4. Aging test
This test is mainly to keep the product energized for use, work continuously for a fixed time, and observe whether there are failures and malfunctions. Strict product control can only be mass-produced after passing the aging test.
5. Test of extreme conditions
This kind of PCBA test is not commonly used, and the main application range is military industry, off-road vehicles, special equipment and other products that will encounter harsh working conditions. The test content includes the limit values of temperature, humidity, drop, water splash, and vibration.
2. How is the PCBA cleaned inspection performed?
The inspection after PCBA cleaning is mostly carried out by visual inspection method. For high-reliability products, special testing equipment and standard methods are required to measure cleanliness. The main criteria for measuring cleanliness are ion pollution and surface insulation resistance.
2. How is the PCBA cleaned inspection performed?
One, cleanliness standards
(1)Ion pollution degree
There is no clear standard for ion pollution in the current SMT chip processing plants. Usually, the US military standard MIL28809 or the American Standards Association standard ANSI/J-001B is quoted.
(2) Surface Insulation Resistance (SIR)
The surface insulation resistance is usually measured by a comb circuit. This method is intuitive and quantifiable, and has the highest reliability, but it is also the most difficult. It requires the design of a comb circuit to measure. It is usually required that the surface insulation resistance SIR ≥ 10 to the 10th power/?.
How is the inspection after PCBA cleaning performed?
2. Inspection method
The cleaning process inspection should be carried out according to the cleanliness requirements of the product.
If it is a product with special requirements such as military products, medical treatment, precision instruments, etc., it is necessary to use measuring instruments such as an Omega (Ω) meter to measure the Na ion dye degree; in addition, usually a shape test piece is used to test the surface insulation resistance.
The Omega (Ω) instrument measures cleanliness by immersing the measured printed circuit assembly (PCBA) in a clean standard solvent, dissolving the ionic contamination on the PCBA surface into the standard solvent, and then calculating the standard solvent’s The content of equivalent sodium ions, which gives the cleanliness of the test piece
Indexes can be inspected by visual inspection methods for a required product.
The visual inspection method needs to be inspected with a 4x microscope. The surface of PCB and components should be clean and free of beads, flux residues and other contaminants. Contaminants should be seen as the judging standard.
