Brief introduction of laser Stencil
Laser Stencil is a template (SMT Laser Stencil) made of SMT patch laser: it is a special SMT mold. The main function is to help the deposition of solder paste or red glue; the purpose is to transfer the exact quantity of solder paste or red glue to the position of PCB where it should be.
Advantages and disadvantages of laser Stencil
Advantages: relative to etched stencil and electroformed stencil, Laser stencil is simple, fast, high precision, easy to use and moderate in price. After polishing, the quality is better and the effect is better. At present, most of the SMT on the market will use laser stencil.
Disadvantages: single thickness, can not make stepped stencil, irregular fillet processing is not perfect.
Classification of laser stencil
Laser stencil can be divided into two sub categories: laser solder paste stencil and laser red glue stencil
1.Solder paste stencil
Most of the SMT use solder paste stencil. Because now the mainstream is the solder paste, solder paste in reflow soldering can better ensure that the components are better pasted on the pad of the PCB board. The problem of false welding and false welding is less. It is suitable for PCB boards with more components, or some high density PCB boards with IC or BGA on the board. But the cost of the solder paste is also high. Good solder paste will affect the tin content on the PCB board to a certain extent.
2.Red plastic Stencil
Laser-cut red plastic SMT stencil, where the opening is the gap between the open pads. Glue the components with the adhesive properties of red glue, and then solder the tin together. Due to the poor adhesion of wave soldering components, it is necessary to carefully check whether the components are faulty or false welding after cooling the tin furnace