Configuration requirements of SMT line

SMT processing production lines can be divided into automatic production lines and semi-automatic production lines according to the degree of automation, and can be divided into large, medium and small production lines according to the scale of the production line.   

Fully automatic production line means that the entire production line equipment is fully automatic. All production equipment is connected into an automatic line through automatic loading machine, buffer connection line and unloading machine. Semi-automatic production line means that the main production equipment is not connected or not fully connected. The printing machine is semi-automatic, requiring manual printing or manual loading and unloading of printed boards.  

The following is an explanation of the workstations involved in a typical SMT production line.  

1. Printing:   

Its function is to print solder paste onto PADs of PCB to prepare for the soldering of components. The equipment used is a printing machine (stencil printing machine), located at the forefront of the SMT production line.  

2. Dispensing:   

It is to drop the glue onto the fixed position of the PCB, and its main function is to fix the components on the PCB. The equipment used is a glue dispenser, located at the forefront of the SMT production line or behind the online solder paste inspecting machine (online SPI).  

3. Mounting:   

Its function is to accurately place the surface mount components to the fixed position of the PCB. The equipment used is a pick and place machine, located behind the printing machine in the SMT production line.  

4. Curing:   

Its function is to melt the glue, so that the surface mount components and the PCB are firmly bonded together. The equipment used is a curing oven, located behind the pick and place machine in the SMT production line.  

5. Reflow soldering:   

Its function is to melt the solder paste, so that the surface mount components and the PCB are firmly bonded together. The equipment used is a reflow furnace, located behind the pick and place machine in the SMT production line.  

6. Cleaning:   

Its function is to remove the harmful welding residues (such as flux, etc.) on the assembled PCB. 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. The equipment used includes magnifying glass, microscope, in-circuit tester (ICT), flying probe tester, automatic optical inspection (Automated Optical Inspection, AOI), X-ray inspection, 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 that has been detected to be faulty. The tool used is a soldering iron, hot air gun, BGA re-work station, which is usually carried out in a rework station.