Since the development of SMT surface mount processing industry, some commonly used terms within the industry have also been widely circulated. As a beginner, it is essential to have an understanding of specialized terminology in the electronic processing industry. It has the characteristics of high assembly density and small product volume. Next, we will introduce the relevant content in detail.

1、 Common terms for circuit board mounting

1. Ideal solder joint:

(1) The surface wettability of the solder joint is good, that is, the molten solder should spread on the surface of the welded metal and form a continuous, uniform, and complete solder coating, with a contact angle of less than or equal to 90 °;

(2) Apply the correct amount of solder, which should be sufficient;

(3) Having a good welding surface, the welding point surface should be continuous, complete, and smooth, but it is not required to have a very shiny appearance;

(4) The position deviation of the pins or solder ends of the components on the solder pads should be within the specified range.

2. Non wetting: The contact angle between the surface of the welded metal and the solder on the solder joint is greater than 90 °.

3. Open soldering: After soldering, the PCB board separates from the surface of the solder pad.

4. Suspension bridge: One end of the component is separated from the solder pad, in an inclined or upright state.

5. Bridge: The solder connection between two or more solder joints that should not be connected, or the solder joints of the solder joints are connected to adjacent wires.

6. Virtual soldering: After soldering, there may be electrical isolation between the solder end or pin and the solder pad.

7. Tip pulling: There are burrs in the solder joint, but it is not in contact with other solder joints or conductors.

8. Solder ball: A small ball of solder that adheres to a conductor, solder mask, or printed circuit board during soldering.

9. Holes: Holes of different sizes appear at the welding point.

10. Position deviation: When the solder joint deviates from the predetermined position in the longitudinal, rotational, or transverse directions within the plane.

11. Visual inspection method: Using an illuminated low-power magnifying glass, visually inspect the quality of PCBA solder joints.

12. Post weld inspection: Quality inspection of PCBA after welding processing is completed.

13. Repair: The repair process for removing local defects in surface assembled components.

14. Surface mount inspection: A quality inspection conducted during or after the installation of surface mounted components to determine if there are any missing, misplaced, incorrectly attached, or damaged components.

2、 Characteristics of PCB SMT

1. High assembly density, small size, and light weight of electronic products. The volume and weight of surface mount components are only about 1/10 of traditional plug-in components. Generally, after using SMT, the volume of electronic products is reduced by 40% to 60%, and the weight is reduced by 60% to 80%.

2. High reliability and strong anti vibration ability. The defect rate of solder joints is low.

3. Good high-frequency characteristics. Reduced electromagnetic and radio frequency interference.

4. Easy to achieve automation and improve production power. Reduce costs by 30% to 50%. Save data, power, equipment, manpower, time, etc.