PCBA Tech - PCBA test method

PCBA test method
1. Manual visual inspection
Visual inspection can be carried out at every step of the PCBA process. Manual visual inspection of PCBA components is the most primitive method in PCBA quality inspection. Use only your eyes and a magnifying glass to check the welding conditions of the circuit and electronic components of the PCBA board, such as the welding method, whether the solder joints are welded, whether the welding is not enough, and whether the welding is incomplete. The magnifying glass is the basic tool for visual inspection, and the metal pins can be used to inspect the soldering defects of the IC leads.

2. Online Tester (ICT)

The online detector is widely used in PCBA processing industry with its excellent detection performance. ICT can almost identify soldering and component problems in PCBA. Fast speed and high stability. Electronic probes test the filled printed circuit board (PCB) to check basic quantities such as short circuit, open circuit, resistance, capacitance, etc., to show whether the component is correctly manufactured.

3. Automatic optical inspection (AOI)

Optical automatic inspection is a non-contact inspection method. Optical automatic inspection plays an important role in inspection. Automatic optical inspection is an automatic visual inspection in the production process of printed circuit boards, in which the camera automatically scans for catastrophic failures (such as missing components) and quality defects (such as round size or shape or component deflection) of the tested PCBA board.

4. Automatic optical inspection (AXI)

With the widespread use of BGA and CSP, typical inspection methods such as ICT cannot detect embedded solder joints of components. AXI can detect misalignment, missing balls, and solder deposits. AXI uses x-rays to pass through solid objects to capture images of them. It can be divided into two types: 2D and 3D.

5. Functional circuit test

The functional circuit test is the last test before the PCBA product goes on the market. Unlike other tests, such as AOI, AXI, and ICT, FCT is designed to make the UUT (unit under test) work in a simulated environment and use the output data to check its actual performance.

6. Sample inspection

Before mass production and assembly, PCB manufacturers and assemblers usually conduct a sample inspection to check whether the SMT equipment is properly prepared to avoid vacuum nozzles or alignment problems during mass production, which may cause PCBA board production problems. This is called first article inspection.

7. Flying probe test

Flying probe probes are suitable for high-complexity PCB inspections that are expensive to inspect. The design and inspection of the flying probe can be completed in one day, and the assembly cost is relatively low. It can check the open circuit, short circuit and direction of the components mounted on the PCB. In addition, it can well recognize component layout and alignment.

8. (Manufacturing Defect Analyzer, MDA)

The purpose of MDA is only to visually test the board to reveal manufacturing defects. Since most manufacturing defects are simple connectivity issues, MDA is limited to measuring continuity. Generally, the tester will be able to detect the presence of resistors, capacitors, and transistors. Protective diodes can also be used to detect integrated circuits to indicate whether components are properly placed.