Solder paste printing is the first process of SMT production, and the quality of printing will directly affect the welding quality of SMT. Solder paste must use SMT steel mesh in the printing process. How to choose SMT solder paste printing steel mesh?
First of all, the frame of SMT solder paste printing steel mesh is made of 1.5 aluminum alloy steel mesh: red rubber + aluminum tape is used. When the aluminum frame is in contact with the glue, a protective paint should be evenly scraped to protect the steel mesh from sufficient surface tension and Good flatness, the distance between the steel mesh and the frame is generally kept at 20MM-50MM. The material of the lead-free solder paste printing steel mesh is generally made of stainless steel. The imported 304# stainless steel has excellent hardness, elasticity and wear resistance, and the two-component epoxy resin has excellent flexibility and adhesion. Steel mesh opening: In order to ensure the hardness of the opening area, the width can not be greater than 2MM, in order to increase the strength of the steel mesh, the pad size is larger than 2MM in the middle of the bridge requires 0.4MM.
Secondly, the stencil logo on SMT solder paste printing steel mesh: in order to facilitate production, the model and time should be engraved on the steel mesh. Steel mesh thickness control: In order to ensure the welding quality, the surface of the steel mesh should be smooth and uniform in thickness, with a spacing of 0.5mm QFP and HIP0402; the thickness of the mesh plate is 0.15M. The stencil thickness of the components above 0.5MMQFP and CHIP0603 is 0.5MM. SMT’s ESD technology requires all operators to have an electrostatic wristband, electrostatic cap, static shoes, and electrostatic overalls.