The quality and production efficiency of SMT patch processing are very critical for PCB circuit boards. If they are the foundation of PCB circuit boards, then SMT process materials are the masonry of pcb circuit boards and play a vital role. Therefore, when designing the SMT process, appropriate process materials must be selected according to the process flow and process requirements. SMT process materials include soldering and patch materials such as solder, solder paste, and adhesive, as well as process materials such as flux, cleaning agent, and heat transfer medium. The following will introduce the main functions of the assembly process materials.
(1) Solder and solder paste
Solder is an important structural material in the surface mount process. Different types of solder are used in different applications, which are used to connect the metal surfaces of the objects to be soldered and form solder joints. Reflow soldering uses solder paste, which is the solder material and at the same time uses its viscosity to pre-fix the SMC/SMD.
(2) Flux
Flux is an important process material in surface assembly. It is one of the key factors affecting the soldering quality, and it is required in various soldering processes, and its main function is to flux.
(3) Adhesives
Adhesives are bonding materials in surface assembly. When the wave soldering process is used, the components are generally pre-fixed on the PCB with an adhesive. When the SMD is assembled on both sides of the PCB, even if reflow soldering is used, the adhesive is often applied to the center of the PCB land pattern to strengthen the fixation of the SMD and prevent the SMD from shifting and falling during the assembly operation.
(4) Cleaning agent
The cleaning agent is used in surface assembly to clean the residue left on the SMA after the soldering process. Under the current technical conditions, cleaning is still an indispensable and important part of the surface mount process, and solvent cleaning is the most effective cleaning method.
The SMT process material is the basis of the surface mount process, and the corresponding assembly process materials are selected for different assembly processes and assembly processes. Sometimes in the same assembly process, due to different subsequent processes or different assembly methods, the materials used will also be different.
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