PCBA Tech - Which voice chip is better in SMT process chip?

SMT is the surface assembly skills (Surface Mount Technology) (abbreviation of Surface Mount Technology), which is currently the most popular skill and process in the electronic voice chip assembly industry.

Advantages of SMT process:

1. The high assembly density is conducive to the miniaturization and light weight of electronic products. The volume and weight of SMD components are only about 1/10 that of traditional plug-in components. Generally, after SMT is selected, 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. SMD components have no lead pins, reducing electromagnetic and radio frequency interference.

4. It is easy to realize automation and improve production efficiency. The packaging of SMD components is made of braided packaging, which is convenient for machine picking and placing, improves production speed, saves materials, power, equipment, manpower, time, etc., and reduces costs by 30% to 50%.

In daily PCB plate making, there are single-sided mixed assembly and double-sided mixed assembly. So the question is, is the SMT process patch of the voice chip better for single-sided or double-sided?

Single-sided hybrid assembly method

The first type is single-sided mixed assembly, that is, SMC/SMD and through-hole plug-in components (17HC) are scattered on different sides of the PCB, but the welding surface is only one-sided. This type of assembling method uses single-sided PCB and wave soldering (dual wave soldering is generally used now), and there are two specific assembling methods.

(1) Paste first. The first assembly method is called the first-attach method, that is, the SMC/SMD is attached to the B side (welding side) of the PCB first, and then the THC is inserted on the A side.

(2) Post-sticking method. The second assembly method is called post-attachment method, which is to first insert THC on the A side of the PCB, and then mount the SMD on the B side.

Double-sided hybrid assembly method

The second type is double-sided hybrid assembly. SMC/SMD and T.HC can be mixed and spread on the same side of the PCB. Together, SMC/SMD can also be spread on both sides of the PCB. Double-sided hybrid assembly uses double-sided PCB, double wave soldering or reflow soldering. In this type of assembling method, there is also a difference between SMC/SMD or SMC/SMD. It is generally selected based on the type of SMC/SMD and the size of the PCB. Usually, the first method is more preferred. Two assembly methods are commonly used in this type of assembly

(1) SMC/SMD and ‘FHC on the same side method. The third listed in Table 2.1, SMC/SMD and THC are on the same side of the PCB.

(2) Different side methods of SMC/SMD and iFHC. The fourth type listed in Table 2-1, put the surface-mounted integrated chip (SMIC) and THC on the A side of the PCB, and put the SMC and the small outline transistor (SOT) on the B side.

(3) This kind of voice chip assembly method is because the SMC/SMD is mounted on one or both sides of the PCB, and the leaded components that are difficult to be assembled on the surface are pierced into the assembly, so the assembly density is appropriately high.