What are the assembly steps in SMT industry?

Assembly mode and process flow of 1 SMT mainly depends on the types of surface mount components (SMA), the types of components used and the conditions of assembly equipment. Generally speaking, SMA can be divided into three ***6 assembly methods: single-sided hybrid assembly, double-sided hybrid assembly and full-surface assembly. Different types of SMA have different assembly methods, and the same type of SMA can also have different assembly methods.

2. Choosing the appropriate assembly method according to the specific requirements of SMT products and the conditions of assembly equipment is the basis of efficient and low-cost assembly production, and it is also the main content of SMT process design.

3. Unilateral mixed assembly mode

The first type is single-sided mixed mounting, that is, SMC/SMD and through-hole plug-in (17HC) are mixed mounted on different sides of PCB, but the soldering side is only one side. This assembly method adopts single-sided PCB and wave soldering (double wave soldering is generally used now), and there are two specific assembly methods.

(1) Paste first. The first assembly method is called the first installation method, that is, SMC/SMD is first installed on the B side (soldering side) of PCB, and then THC is inserted on the A side.

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

Second, the double-sided mixed assembly mode

The second is double-sided hybrid assembly. SMC/SMD and T.HC can be mixed and distributed on the same side of PCB, and SMC/SMD can also be distributed on both sides of PCB. Double-sided mixed installation adopts double-sided PCB, double wave soldering or reflow soldering. In this assembly mode, there is also a difference between pasting SMC/SMD first or pasting SMC/SMD later. Generally, it is reasonable to choose according to the type of SMC/SMD and the size of PCB, and the first paste method is usually adopted. This kind of assembly is usually used in two ways.

(1)SMC/SMD and FHC are on the same side. The third type listed in Table 2-L, SMC/SMD and THC are located on the same side of PCB.

(2) Different ways of 2)SMC/SMD and iFHC. The fourth type listed in Table 2- 1, surface mount integrated chip (SMIC) and THC are placed on the A side of PCB, and SMC and SOT are placed on the B side.

(3) This assembly method has a high assembly density because SMC/SMD is attached to one or both sides of the PCB, and lead elements difficult to assemble on the surface are inserted and assembled.