SMT Basic Process Components

- Jan 09, 2019-

SMT basic process components


The basic process components of SMT include: silk screen (or dispensing), placement (curing), reflow soldering, cleaning, inspection, rework



Printing: Its function is to print solder paste or patch glue on the pads of the PCB to prepare for soldering of components. The equipment used is a screen printing machine (solder paste printing machine), which is located at the forefront of the SMT production line.


Dispensing: It is a fixed position where the glue is dripped onto the PCB. Its main function is to fix the components to the PCB. The equipment used is a dispenser, located at the forefront of the SMT line or behind the inspection equipment.


Mounting: Its function is to accurately mount surface-mounted components to a fixed position on the PCB. The equipment used is a placement machine located behind the screen printing machine in the SMT production line.


Curing: Its function is to melt the patch glue, so that the surface-mount components and the PCB board are firmly bonded together. The equipment used is a curing oven located behind the placement machine in the SMT line.


Reflow soldering: The function is to melt the solder paste to firmly bond the surface-mount components to the PCB board. The equipment used is a reflow oven located behind the placement machine in the SMT line.


Cleaning: Its function is to remove the welding residues on the assembled PCB board that are harmful to the human body, such as flux. The equipment used is a washing machine, the position can be fixed, it can be online or not.


Inspection: Its function is to test the quality and assembly quality of the assembled PCB. The equipment used includes a magnifying glass, a microscope, an on-line tester (ICT), a flying probe tester, an automatic optical inspection (AOI), an X-RAY inspection system, and a function tester. The position can be configured in a suitable place on the production line according to the needs of the inspection.


Rework: Its role is to rework PCB boards that have failed. The tools used are soldering irons, rework stations, and the like. Configure anywhere in the production line.