The basic process components of SMT include: silk screen (or dispensing), placement (curing), reflow soldering, cleaning, inspection, rework
SMT steel mesh
1. Silk screen: Its function is to print solder paste or patch glue on the pad of PCB to prepare for soldering of components. The equipment used is a screen printing machine (screen printer), located at the forefront of the SMT production line.
2, dispensing: it is to drop the glue to the fixed position of the PCB, its main role 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.
3. Mounting: Its function is to accurately mount the surface-assembled 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: The function is to melt the patch glue, so that the surface-assembled 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.
5, reflow soldering: its role is to melt the solder paste, so that the surface assembly components and PCB board firmly bonded together. The equipment used is a reflow oven located behind the placement machine in the SMT line.
6. Cleaning: The function is to remove the welding residue (such as flux) which is harmful to the human body on the assembled PCB board. The equipment used is a washing machine, the position can be fixed, it can be online or not.
7. Inspection: The 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.
8, repair: its role is to detect the failure of the PCB board rework. The tools used are soldering irons, rework stations, and the like. Configure anywhere in the production line.
At present, advanced electronic products, especially in computer and communication electronic products, have generally adopted SMT technology, so as the progress of the SMT technology will become more and more popular, let's take a look at what it has!
What are the characteristics of SMT steel mesh:
The assembly density is high, the size of the electronic product is small, and the weight is light. The volume and weight of the chip components are only about 1/10 of that of the conventional plug-in components. After the SMT is generally used, the volume of the electronic product is reduced by 40% to 60%, and the weight is reduced by 60%. 80%.
High reliability and strong anti-vibration ability. The solder joint defect rate is low.
High frequency characteristics are good. Reduced electromagnetic and radio frequency interference.
Easy to automate and increase productivity. Reduce costs by 30% to 50%. Save materials, energy, equipment, manpower, time, etc.
Why use SMT:
The pursuit of miniaturization of electronic products, the previously used perforated plug-in components can not be reduced
Electronic products are more complete, and the integrated circuits (ICs) used have no perforated components, especially large-scale, highly integrated ICs, which have to use surface mount components.
Product batching, production automation, the factory must produce high-quality products at low cost and high yield to meet customer needs and strengthen market competitiveness
Development of electronic components, development of integrated circuits (ICs), multi-application of semiconductor materials