The role of SMT is to accurately mount surface assembled components to the fixed position of the PCB. The equipment used is the SMT machine, which is located behind the printing press in the SMT production line. SMT has high assembly density, small size and light weight of electronic products, the volume and weight of the patch components are only about 1\/10 of the traditional plug-in components, generally after the use of SMT, the volume of electronic products is reduced by 40% to 60%, and the weight is reduced by 60% to 80%. High reliability and strong vibration resistance. Low defect rate of solder joint. Good high frequency characteristics. Reduced electromagnetic and radio frequency interference. Easy to automate and improve production efficiency. Reduce the cost by 30%~50%. Save materials, energy, equipment, manpower, time, etc.