SMT chip processing

Smt patch is actually a series of PCB-based processing processes.

SMT is a surface mounting technology, which is very popular in electronic assembly industry. SMT is based on PCB. First, solder paste is printed on the pad of PCB bare board. Then the electronic components are attached to the pads of the PCB bare board with a mounter (further reading: overview of components and structure of the mounter). Then the PCB board is sent to reflow soldering for welding. SMT is to attach electronic components to PCB bare board through a series of processes.

Introduction of SMT process flow

The basic process elements of SMT mounting: screen printing, inspection, mounting, reflow soldering, cleaning, inspection and repair.

1. Screen printing: By omitting to print solder paste or solder paste on the pads of PCB, it prepares for the soldering of components. The equipment used is (steel screen printing machine), which is located at the forefront of SMT production line.

2. Inspection: Check the printing quality of solder paste on the printing machine, check the amount of tin and the position of solder paste printed on the PCB, check the smoothness and thickness of solder paste printing, check whether the solder paste printing is offset, and check whether the stripping of the solder paste steel screen of the printing machine is sharp. The equipment used is (SPI) solder paste thickness detector. Further reading: What is SPI? What does SPI test mean? What is the function of SPI test equipment?

3. Installation: Its function is to accurately install the surface assembly components to the fixed position of PCB. The equipment used is a mounter, which is located behind the screen printer of SMT production line.

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

5. Cleaning: Its function is to remove welding residues harmful to human body such as flux on the assembled PCB. The equipment used is a cleaning machine, and the location can be not fixed, online or offline.

6. Inspection: Its function is to inspect the welding quality and assembly quality of the assembled PCB. The equipment used includes magnifying glass, microscope, on-line tester (ICT) and automatic optical inspection (AOI). Further reading: What is AOI? The automatic optical inspection equipment aoi, X-ray inspection system and function tester are introduced in detail. This position can be configured in a suitable position on the production line according to the needs of detection.

7. Rework: Its function is to rework the PCB board whose fault has been detected. Tools used include soldering iron, maintenance workstation, etc. Configured at any position of the production line.