The circuit board is mainly composed of pads, vias, mounting holes, wires, components, connectors, fillings, electrical boundaries, etc.
Pad: metal hole for soldering component pins;
Vias: There are metal vias and non-metal vias, of which metal vias are used to connect component pins between layers;
Mounting holes: used to fix the circuit board;
Conductor: Electrical network copper film used to connect component pins;
Connectors: components used for connection between circuit boards;
Filling: copper applied to the ground wire network, which can effectively reduce the impedance;
Electrical Boundary: Used to determine the size of the circuit board, and all components on the circuit board must not exceed this boundary. There are regularly and densely distributed connection line nodes from several square centimeters to tens of square centimeters on the bottom surface. This surface mount component with many dense connection lines is mounted on the PCB to form an application circuit with corresponding functions.
In this case, the node between the component and the PCB board cannot be observed by the human eye except at the periphery. However, in actual production practice, the quality of different nodes cannot be perfect. Each spot weld may have various casting defects (eg bridging, void soldering, solder balls, insufficient wetting, etc.), and this possibility will seriously affect the stability of the circuit.
X-ray inspection machine: It is the first choice for testing. With the development of innovative technologies, ultra-high-resolution automatic X-ray inspection equipment not only provides time-saving, worry-free and reliable assurance for assembling BGA components, but also plays a key role in the common failure analysis of electronic equipment, improving common fault checking efficiency.
The ray perspective view of the x-ray inspection system can clearly display the compensation distribution of spot welding thickness, shape and quality, which can fully reflect the welding quality of spot welding, and can perform quantitative analysis.
During the collision, the lost kinetic energy will be released in the form of X-rays due to the sudden deceleration of the electrons. The wavelength is short, but the electromagnetic radiation is high. For locations where the sample cannot be detected with the naked eye, the change in light intensity as the X-ray machine rays penetrate materials of different densities is recorded, and the resulting contrast effect can be used to form an image to show the internal structure of the object under test. When the test object is destroyed, observe the problem area inside the test object.