Asthe current SMT technology continues to mature, the components in the PCBAassembly process have become smaller and smaller, making the PCBA morepowerful. At the same time, it also brings huge challenges to testing andinspection. Testing is a crucial step to ensure that high-quality PCBA productsare delivered to customers. Inspection and testing can reduce processing risks.The following is a collection of several test methods in the PCBA processingindustry.

1.Manual visual inspection

Visualinspection can be achieved at every step of the PCBA process. PCBA assemblymanual visual inspection is the most primitive method in PCBA qualityinspection. It only uses eyes and a magnifying glass to check the weldingconditions of the circuit and electronic components of the PCBA board, such asthe welding method, whether the solder joints are bridged, whether there isless soldering or welding failure Completeness. In the visual inspection, themagnifying glass is the basic tool, and the metal needle can be used to checkthe welding incompleteness on the IC lead.

2.Online tester (ICT)

Theonline tester is widely used in the PCBA processing industry because of itsexcellent testing and inspection performance. ICT can almost find soldering andcomponent problems in PCBA. It has high speed and high stability. Among them,the electrical probe test fills the printed circuit board (PCB) to check shortcircuits, open circuits, resistance, capacitance and other basic quantities toshow whether the components are properly manufactured.

3.Automatic optical inspection (AOI)

Automaticoptical inspection is a non-contact testing method. Automatic opticalinspection plays an important role in inspection. Automatic optical inspectionis an automatic visual inspection in the manufacturing process of printedcircuit boards, in which the camera automatically scans for catastrophicfailures (such as missing parts) and quality defects (such as rounded cornersize or shape or component skew) of the tested PCBA board.

4.Automatic optical inspection (AXI)

Forthe widespread use of BGA and CSP, typical inspection methods like ICT cannotinspect the embedded solder joints of the component. AXI can test formisalignment, lack of balls and solder deposits. AXI uses X-rays to penetratesolid objects to capture their photos. It can be divided into two types: 2D and3D.

5.Functional circuit test

Thefunctional circuit test is the last test before the PCBA product goes on themarket. Unlike other tests (such as AOI, AXI, and ICT), FCT is designed to makeUUT (unit under test) work in a simulated environment and use output data tocheck its actual performance.

6.Sample inspection

Beforemass production and assembly, PCB manufacturers and assemblers usually conducta first sample inspection to check whether the SMT equipment has been properlyprepared, so that vacuum nozzles or alignment problems can be avoided in massproduction, which can cause problems in PCBA board production. This is calledthe first inspection.

7.Flying probe tester

Flyingprobe probes are suitable for the inspection of high-complexity PCBs thatrequire expensive inspection costs. The design and inspection of the flyingprobe can be completed in one day, and the assembly cost is relatively low. Itcan check the open circuit, short circuit and direction of the componentsmounted on the PCB. In addition, it works well in identifying component layoutand alignment.

8.Manufacturing Defect Analyzer (MDA)

<span lang="EN-US" style="font-family: 宋体; font-size: 10.5pt; mso-ascii-theme-font: minor-fareast; mso-fareast-theme-font: minor-fareast; mso-hansi-theme-font: minor-fareast; mso-bidi-font-size: 11.0pt; mso-bidi-font-family: "Times New Roman"; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">The purpose of MDA is only to visually test theboard to reveal manufacturing defects. Since most manufacturing defects aresimple connection problems, MDA is limited to measuring continuity. Usually,the tester will be able to detect the presence of resistors, capacitors andtransistors. You can also use protective diodes to detect integrated circuitsto indicate whether the components are properly plac