What is the SMT stencil

SMT stencil, also known as steel, its main function is to help the solder paste deposition, transfer the accurate amount of solder paste to plate (bare PCB) on accurate position, appearance is shown in figure 2-1-27. Stencil consists of net frame, wire mesh and steel sheet. Sheet steel, there are many holes, these holes position corresponding to the location of the PCB need to be printed. When use, place the PCB down to the bottom of the steel net, the solder paste by steel net fixed position of holes printing on the PCB. Solder paste blockage in the steel net is less, the more you will deposit on the PCB. Therefore, when there is bad situation in the printing process, should first check the status of the steel plate.