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Sep.2022 13
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SMT Testing Technology Service Description
Introduction
As a professional home appliance controller supplier, Elecontro® has advanced technical equipment and complete quality inspection procedures. The inspection method is one of the indispensable technologies today, and inspection is the guarantee of product quality and environmental safety. In order to improve everyone's understanding of Elecontro® inspection technology and inspection equipment, this article will introduce the types of SMT inspection technology.
Details
As a professional home appliance controller supplier, Elecontro® has advanced technical equipment and complete quality inspection procedures. The inspection method is one of the indispensable technologies today, and inspection is the guarantee of product quality and environmental safety. In order to improve everyone's understanding of Elecontro® inspection technology and inspection equipment, this article will introduce the types of SMT inspection technology.
Types of SMT testing techniques:
(1)Manual visual inspection
Manual visual inspection is a method of inspection with the naked eye. Its detection range is limited and it can detect missing components, polarities, correct and incorrect models, bridges and partial welds. However, manual visual detection is susceptible to human subjective factors, and therefore has high instability. When dealing with 0603, 0402 and small-pitch chips, manual visual inspection is difficult, especially when a large number of BGA components are used, manual visual inspection is almost powerless to check the soldering quality.
(2)Flying probe test
Flying probe test is a machine inspection method, which is realized by energizing the component with two probes, and can detect defects such as component failure and poor performance. This test method is more suitable for plug-in PCBs and low-density PCBs with components above 0805. However, the miniaturization of components and the high density of products make the shortcomings of this test method obvious. For 0402-level components, due to the small area of ​​solder joints, the probes cannot be accurately connected, especially for high-density consumer electronics, the probes will not be able to touch the solder joints. In addition, the use of electrical connections such as parallel capacitors and resistors cannot accurately measure PCBs. so,
(3)ICT bed of needles test
ICT bed of needles test is a widely used test technique. The advantage is that the test speed is fast, and it is suitable for large quantities of single-variety products. However, with the enrichment of product varieties, the improvement of assembly density and the shortening of new product development cycles, its limitations are becoming more and more obvious. The main disadvantages are: the need to specially design test points and test molds, long production cycle, high price, and long programming time; difficult and inaccurate testing caused by the miniaturization of components; after the PCB design is changed, the original test mold will not be available.
(4)Automatic optical inspection AOI 
Automatic optical inspection AOI is a detection method that has emerged in recent years. It obtains images of components or PCBs through CCD photography, and then judges defects and failures through computer processing and analysis and comparison. Its advantages are: fast detection speed, short programming time, and can be placed in different positions of the production line, which is convenient for timely detection of faults and defects, so that production detection can be combined into one. Therefore, it is a widely used detection method at present. But the AOl system also has shortcomings, such as the inability to detect circuit errors and detect invisible solder joints.
(5) Functional test
ICT can effectively find various defects and faults in the SMT assembly process, but cannot evaluate the performance of a system consisting of an entire PCB circuit board at clock speed. Functional testing can test whether the entire system can achieve the design goals. It takes the unit under test on the circuit board as a functional body, provides input signals to it, and detects output signals according to the design requirements of the functional body. This test is to ensure that the board is working as designed. The simplest method of functional testing is to connect a dedicated circuit board on an assembled electronic device to the corresponding circuit of the device and then apply a voltage. If the device is working properly, the board is marked as good.