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PCBA Tech
What are the basic process components of SMT?
PCBA Tech
What are the basic process components of SMT?

What are the basic process components of SMT?

2021-11-11
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Author:Downs

SMT is surface mounting technology (surface mounting technology) (abbreviation of Surface Mounting Technology), which is called surface mounting or surface mounting technology. It is the most popular technology and craft in the electronics assembly industry at present. It is a kind of surface mount components (SMC/SMD for short, chip components in Chinese) that are packaged in a matrix arrangement without leads or short leads or balls, mounted on the surface of a Printed Circuit Board (PCB) or Circuit assembly technology in which the surface of other substrates is soldered and assembled by reflow soldering or dip soldering.

SMT placement machine is the equipment used in the pre-reflow soldering process,

pcb board

that is to say the same SMT production line, the placement machine process is before reflow soldering, but it will not be used in wave soldering. Simply put, the placement machine and reflow soldering are the necessary processes for SMT production. The placement machine is responsible for mounting components. Reflow soldering is to solder the mounted PCB board. It is configured in the dispenser or wire After the screen printer, it is a device that accurately places surface mount components on PCB pads by moving the placement head.

SMT basic process components

Including: screen printing (or dispensing), placement (curing), reflow soldering, cleaning, inspection, rework

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

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

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

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

5. Reflow soldering: Its function is to melt the solder paste, so that the surface assembly components and the PCB board are firmly bonded together. The equipment used is a reflow oven, located behind the placement machine in the SMT production line.

6. Cleaning: Its function is to remove the solder residues such as flux that are harmful to the human body on the assembled PCB board. The equipment used is a washing machine, and the location may not be fixed, it may be online or offline.

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

8. Rework: Its function is to rework the PCB boards that have failed to detect faults. The tools used are soldering irons, rework stations, etc. Configured at any position in the production line.