SMT Technological Process

The basic process components of SMT include dispending, placement(or curing), reflow soldering, cleaning, inspection, and repair.

1. Silk screen print: the function is to print solder paste or adhesives onto the PCB pads to prepare for component jointing. The equipment is a mesh-printer which located at the forefront of the SMT production line.

2. Dispensing: it is to drip glued onto the fixed position, and its main function is to fix the components on the PCB board. The equipment is a glue dispense located at the forefront of the SMT production line or behind the testing equipment.

3. Mounting: its function is to accurately mount the surface mounting components to the fixed position of the PCB. The equipment is a placement machine located behind the screen printing in the SMT line.

4. Placement: Its function is to melt the adhesives, so that the SMD and the PCB board are firmly bonded together. The equipment is a curing oven which located behind the Mounter in the SMT production line.

5. Reflow solder: Its function is to melt the solder paste, so that the SMD and the PCB board are firmly bonded together. The equipment is reflow soldering which located behind the Mounter in the SMT production line.

6. Cleaning: Its function is to remove the solder residues such as flux that are harmful to the human on the assembled PCB board. The equipment is a washing machine, and the location can be variable, online or offline.

7. Inspection: Its function is to inspect the soldering quality and assembly quality of the assembled PCB board. The equipment includes magnifying glass, microscope, integrated circuit tester (ICT), flying probe testing, automatic optical inspection (AOI), X-RAY testing system, function tester, etc. The position can be configure in a suitable place according the testing needs.

8. Rework: Its function is to rework the PCB board that has failed to detect. The tools used are soldering iron, rework station, etc. Configured at any position in the production line.