In SMT patch, the most common patch assembly methods can be divided into single-sided assembly, double-sided assembly, single-sided mixed assembly and double-sided mixed assembly. Among them, the types of circuit substrates used in single-sided assembly and double-sided assembly are divided into single-sided PCB and double-sided PCB, and mixed assembly is a little more complicated.

Single-sided mixed assembly can be divided into first and post-attached methods, while double-sided assembly is divided into SMC/SMD and FHC on the same side, SMC/SMD and IFHC on different sides, and different assembly methods correspond to different processing processes.

SMT placement equipment mainly includes solder paste printers, placement (chip) machines, reflow soldering machines, wave soldering machines, testing equipment, rework equipment and cleaning equipment. The following Sanjing will give you a brief introduction:

①The solder paste printer is located at the forefront of the SMT production line and is used to print solder paste or patch glue. The solder paste or patch glue is correctly printed on the pads or corresponding positions of the printed board to prepare for component placement. Printing machines are generally divided into three types: manual printing machines, semi-automatic printing machines or fully automatic printing machines.

②The placement machine is located behind the printing machine. It is the most technical, complex and expensive equipment in the SMT production line. Its function is to take the surface mount components out of the package and accurately install them on the fixed position of the printed circuit board. The placement function and production capacity of the SMT production line mainly depend on the function and speed of the placement machine, and the configuration of the placement machine should also be determined according to the type and output of the product.

③The reflow soldering machine is also called the reflow soldering machine, located behind the placement machine, mainly to provide a heating environment to melt the solder paste pre-distributed on the printed board, so that the surface mount components and PCB pads can be soldered Paste alloys are reliably bonded together.

④ Wave soldering machine. The welding equipment that uses the cyclic flow of molten solder to contact the soldering surface of the PCB with components and moves relative to a certain speed to achieve group soldering. It is mainly used in the traditional through-hole plug-in printed circuit board assembly process, as well as surface assembly and Mixed assembly process of through-hole plug-in components. Compared with manual welding, it has high production efficiency, good welding quality and high reliability.

⑤The inspection equipment is mainly for quality inspection of the mounted PCB. The main equipment used are magnifying glass, microscope, automatic optical inspection instrument (AOI), online tester (ICT), X-RAY inspection system, functional tester, etc. . The installation position can be set according to the needs of detection.

⑥Rework equipment is mainly used to rework and repair PCBs that have been detected to be faulty. The tools used are mainly soldering irons, rework workstations, etc.

⑦The cleaning equipment mainly removes the electrical properties of the mounted PCB or the welding residues (such as flux) that are harmful to the human body. The cleaning equipment mainly includes ultrasonic cleaning or special cleaning fluid. If no-clean solder is used, cleaning is generally not necessary.

The above is about the SMT assembly method and equipment content, I hope it can be helpful to everyone!