8/31/2023 0 Comments Pcba transistor tester![]() Its principle is to test the electrical properties and electrical connections of the assembled PCBA board-on-board components to check manufacturing defects and component failures. The online tester is also called flying probe tester. At present, in artificial manufacturing, the manual visual test method is only used as a supplementary auxiliary method. This test exposed the subjectivity of manual visual inspection, which was neither reliable nor economical. The fourth inspector is only 6% consistent with the first three. As a result, the first inspector found 44% of the defects, the second inspector agreed with the first 28%, and the third inspector agreed with the first two 12%. Someone once conducted such a test, which allowed four experienced inspectors to perform four inspections on the solder joint quality of the same board (medium complexity circuit board, such as a 300-component, 3500-node single panel). The quality of PCBA processing cannot be guaranteed. The mutual obstruction of densely populated components, as well as the micro-packages (0201) and "invisible" solder joints (such as BGA, CSP, and flip chip component FCA) that have appeared widely in recent years. The density of PCBA has become higher and higher with the continuous miniaturization of components. However, with the development and application of SMT processing, electronic products are developing in the direction of lightness, thinness, and miniaturization. The operator's eyes are used to look at the goods, supplemented by a magnifying glass and a microscope. MVI is to confirm the quality of component placement, insertion, and soldering on PCBA through human visual comparison. There are three ways to verify that the board is functioning properly. After the circuit board is assembled by SMT, it will first use AOI to use optical to check the problems such as part shift, short circuit, tombstone, missing parts, etc., then pass the circuit test of ICT or MDA, and then pass the functional verification test (FVT). But the investment in additional equipment is large. ![]() Traditional visual inspection of the PCB assembly process does not completely eliminate poor soldering, but also requires automatic X-ray non-destructive testing. It can also be divided into two categories according to whether the PCBA is in contact with the test equipment: one is contact testing technology, and the other is non-contact testing technology. They can be classified into two categories according to whether the PCBA is powered on: one is electrical test technology, and the other is non-electrical test technology. ![]() Commonly used are Manual Visual Inspection (MVI), In-Circuit Tester (ICT), Automatic Optical Inspection (AOI), Automatic X-ray Inspection (AXI), Function Tester, referred to as FCT. There are many types of testing technologies currently used in the field of electronic assembly testing. The main assembly failure mode is poor welding, which accounts for 57% of all assembly failures.Īs the design of PCBA boards tends to be miniaturized, smaller devices, and miniaturization (high density) of electronic assemblies are more and more, causing PCBA solder joint defects, difficult detection and positioning, poor visibility and maintainability and even irreparable, the potential risk of failure increases. Sometimes PCBA is delivered to customers, and then malfunctions such as bombers, blasting boards, and poor functions occurred later. Most of the problems in the assembly process, such as missing parts, damaged parts, wrong parts, and offsets, can be checked visually, but the welding quality is difficult to judge visually. ![]() The first two problems require advance measures to prevent them from occurring. Poor quality in the assembly manufacturing process comes from three aspects: design problems, material problems, and assembly problems. Control the difference and do not allow mutation. The uniform requirements for PCB assembly are consistency and correctness. ![]()
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