The SMT production system formed by surface assembly equipment such as surface coating equipment, placement machines, welding machines, cleaning machines, and testing equipment is customarily called SMT production lines.

At present, the varieties and specifications of surface mount components are not yet complete, so sometimes part of through-hole insertion (THT) components are still needed in surface mount components (SMA). Therefore, generally speaking, the surface mount components often have both inserts and mounts, and only a part of them all use SMC/SMD. The assembly of both the insert and the mount is called hybrid assembly, and the assembly that all adopts SMC/SMD is called full surface assembly.

According to different assembly objects, assembly processes and assembly methods, the SMT production line has a variety of assembly methods. The following Guangzhou Jujin Technology Co., Ltd. will introduce you to the general process of the SMT production line. The solder paste coating method, soldering method and dispensing process are all different depending on the wiring method.

1. Printing

The solder paste or patch glue is printed on the pads of the PCB to prepare for the soldering of the components. The equipment used is a solder paste printer, which is located at the forefront of the SMT production line.

2. Dispensing

It drops the glue onto the fixed position of the PCB, and its main function is to fix the components on the PCB when using wave soldering. The equipment used is a glue dispenser, located at the forefront of the SMT production line or behind the testing equipment.

3. Mounting

The surface mount components are accurately installed on the fixed position of the PCB. The equipment used is a placement machine, located behind the solder paste printer in the SMT production line.

4. SMD glue curing

When using patch adhesive, cure the patch adhesive so that the surface mount components and PCB are firmly bonded together. The equipment used is a curing oven, located behind the placement machine in the SMT production line.

5. Reflow soldering

Melt the solder green to make the surface mount components and the PCB firmly bonded together. The equipment used is a reflow oven, which is located behind the placement machine in the SMT production line.

6. Cleaning

Remove the solder residues, such as flux, that are harmful to the human body or the product on the assembled PCB. The equipment used is a washing machine, and the location may not be fixed, it may be online or offline. When no-clean welding technology is used, this process is not provided.

7. Detection

The assembled SMA (surface mount component) is inspected for welding quality and assembly quality. The equipment used includes magnifying glass, microscope, online tester (ICT), flying probe tester, automatic optical inspection (AOI) tester, X-Ray tester, functional tester, etc. The location can be configured in a suitable place on the production line according to the needs of the inspection.

8. Repair

Repair the faulty SMA. The tools used are electric soldering irons, rework workstations, etc. Configured at any position in the production line.